A & I:  ACRONYM – Assembly and Installation.

A & R:  ACRONYM – Automation and Robotics.

A.A.B.A.:  Ambient Air Breathing Apparatus.

AB 1807 (Tanner):  A California state law (Health and Safety Code section 39650 et seq.) which became effective in January of 1984 and established the framework for California’s toxic air contaminant identification and control program.

AB 2588 (Connelly) Air Toxics “Hot Spots” Information and Assessment Program:  A California program (Health and Safety Code Section 44300 et seq.) which requires certain stationary sources to report the type and quantity of specific toxic substances they routinely release into the air.  The program identifies high priority facilities and requires facilities posing significant risks to notify all exposed individuals.

AB 2766 (Sher) Motor Vehicle Fee Program:  A program that permits air district and local governments to allocate vehicle registration surcharge fees to projects that reduce motor vehicle emissions such as zero-emission vehicles, bike lanes, and trip reduction programs.

Abatement:  The reduction of pollutant discharge by means of process modification, shutdown or addition of control equipment.  Corrective action to stop or clean up pollution or nuisance.  The reduction or elimination of pollution.

Above Grade:  The portion of a foundation wall or other building assembly above ground level.

Abrasion:  The wearing away of a solid surface by friction.  Damage caused by wearing, grinding, friction, or scraping.

Abrasion, Flex:  Fabric wear in a creased area caused by excessive bending, usually associated with cage contact used in bag house filtration.

Abrasion Resistance:  Ability of a fiber or fabric to withstand surface wear.

Abrasive Blasting Respirator:  A continuous flow air-line respirator constructed so that it will cover the wearer’s head, neck and shoulders.  It is designed to protect the wearer from inhalation of, impact of, and abrasion by materials used or generated in abrasive blasting.

Abrasive Cleaners:  Products that clean through abrasive or scouring action.

Abrasive Dust:  Coarse particles such as sand, metallic compounds, ceramic and glass, that can cause rapid wear on ductwork, air cleaners and fans.

Abridged Life Cycle Assessment (ALCA):  A simplified methodology to evaluate the environmental effects of a product or activity holistically, by analyzing the most significant environmental impacts in the life cycle of a particular product, process, or activity.  The abridged life cycle assessment consists of three complimentary components, restricted inventory analysis, abridged impact assessment, and improvement analysis, together with an integrative procedure known as “Scoping.”

ABS:  (Acrylonitrile butadiene styrene) Rigid black plastic pipe used only for drain lines. A common thermoplastic used to make light yet rigid molded products such as vacuum cleaners, helmets, automobile body parts, etc.  It has excellent impact resistance and durability.

Absolute:  A degree of filtration that guarantees 100% removal of suspended solids over a specified size found in the filtrate.

Absolute, AEC, or CWS Filter:  Obsolete term for HEPA filters.

Absolute Containment:  Capacity for completely retaining any specified substance. (In the present sense, the specified Class III safety cabinet is an example.)

Absolute Efficiency:  An arbitrary filter efficiency rating.

Absolute Filter:  See HEPA filter.

Absolute Filtration Rating:  The diameter of the largest hard spherical particle that will pass through a filter under specified test conditions. This is an indication of the largest opening in the filter cloth.

Absolute Humidity:  Air moisture content expressed in grains (or pounds) of water vapor per pound of dry air.  Amount of moisture in the air, indicated in grains per cubic foot.  The amount of water vapor present in a unit volume of air, usually expressed in kilograms per cubic meter (see Humidity and Relative Humidity).  The mass of water vapor per unit volume of air.  The humidity of the air measured by the number of grains of water vapor present in one cubic meter of air.

Absolute Micron Rating:  All (not just 98%) particles larger than the stated micron size have been removed from the fluid being filtered.

Absolute Pressure:  Pressure referred to as perfect vacuum.  It is the sum of gauge pressure (+ or -) and atmospheric pressure.  Abbreviated “psia” for pounds per square inch absolute.  One atmosphere (14.7 psi) greater than gauge pressure.

Absolute Temperature:  Temperature measured from absolute zero using an absolute temperature scale (e.g. Kelvin).  The temperature of a body referred to the absolute zero, at which point the volume of an ideal gas theoretically becomes zero. (Fahrenheit scale is minus 459.67°F / Celsius scale is minus 273.15°C).

Absolute Viscosity:  The force per unit area required to produce unit relative velocity between two parallel areas of fluid distance apart; also called coefficient of viscosity.

Absolute Viscosity (Dynamic):  The force in newton required to move a fluid layer of one square meter area and a thickness of one meter with a velocity of one meter per second.

Absolute Zero:  Temperature at which all molecular motion ceases (-460 °F, -273.15 °C, and 0 K).  The lowest temperature theoretically attainable on the Kelvin scale (approximately 273.16° C).

Absolute Zero Temperature:  The lowest temperature theoretically attainable on the Kelvin scale. Approximately -273.16o C.

Absorb:  A method to trap liquids or gases by causing them to penetrate into the absorbent material.

Absorbed Dose:  The absorbed dose is the energy deposited in an organ or tissue per unit mass of irradiated material.  The common unit for absorbed dose is the rad, which is equivalent to 100 egs per gram of material.  The international scientific community has adopted the use of different terms.  The SI unit of absorbed dose is the joule per kilogram (J kg-1) and its special name is the gray (Gy).  One Gy is the same as 100 rad.  Amount of energy imparted to matter by ionizing radiation per unit mass of irradiated material, in which the absorbed dose is expressed in units of rad or gray (l rad = 0.01 gray).

Absorbent:  A material which extracts one or more substances from a liquid or gaseous medium which it contacts and charges physically or chemically, or both (e.g. soled absorbent:  Calcium chloride, liquid absorbent: solutions of lithium chloride, lithium bromide, and ethylene glycols).  A substance with the ability to absorb another substance.

Absorber:  A kind of scrubber utilizing the absorption principle.  An object absorbing another object or radiation (e.g. the blackened surface within a solar collector, which absorbs the solar radiation converting it to heat.  These surfaces usually absorb solar radiation but do emit a limited amount of radiative heat because of the so-called spectral selective coatings applied to the surface).

Absorptance:The ratio of a solar energy absorbed to incident solar.  The ratio absorbed objects or radiation.  (For solar energy the ratio of absorbed to incident solar radiation on a surface).  Also called absorbtivity.

Absorptance of a Glazing Material:  In this context the absorption of solar energy in the glazing material occurring throughout the thickness of a glazing material.  The absorptance is the fraction absorbed related to the incident overall radiation (involving multiple reflections).  The absorptance is different for different wavelengths (colored glazing) and angles of incidence.  The transmittance + absorptance + reflectance = 1.

Absorptance of an Opaque Surface:  The ratio of the radiation absorbed at a surface relative to the incident radiation on that surface.  The absorptance is different for different radiation wavelengths and angles of incidence.  The absorptance of normally incident radiation however is always numerically equal to the emittance of the surface for the same wavelength.  ‘Black body’ is a theoretical perfect absorber with an absorptance of 1 for all wavelengths: a typical matt black paint has an absorptance of 0.97 for normal solar radiation and 0.95 for long-wave (thermal) radiation.  For any wave length and angle of incidence, for an opaque surface, absorptance + reflectance = 1.

Absorption:  (gen) The taking in, incorporation or reception of gases, liquids, light or heat.  (phys/chem.) Penetration of one substance into the inner structure of another (cf. adsorption, in which one substance is attracted and held on the surface of another). Occurs between a gas or vapor and a liquid.  (pharm.) The process of movement of a drug from the site of application into the extracellular compartment of the body.  A process where an object absorbs another object or radiation.  For example, a process whereby a material extracts one or more substances present in an atmospheric or mixture of gases or liquids accompanied by the material’s physical and/or chemical changes.  A solid material’s ability to draw in and hold liquid or gas.  In chemistry, is a physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase – gas, liquid or solid material.  This is a different process from adsorption, since the molecules are taken up by the volume, not by surface.  A more general term is sorption which covers adsorption, absorption, and ion exchange.  In physics, the taking up of light, heat, or other energy by molecules.  The absorbed energy is converted into heat.  Absorption in chemistry is the taking up of one substance by another. For example, a gas such as oxygen may be absorbed, or dissolved, in water.  In the HVAC industry heat energy is absorbed from the medium being cooled and transferred in the refrigerant.  Retention of liquids in the bulk of the fabric where the liquid is retained by filling up of void spaces, i.e. pores of the fiber, between fibers in a yarn and between yarns in the fabric.  The process by which a liquid adheres to the absorbent material but does not penetrate the fibers or particles themselves.  The process of one substance entering into the inner structure of another.  The uptake of water, other fluids, or dissolved chemicals by a cell or an organism (as tree roots absorb dissolved nutrients in soil.)  In physics, the taking up of light, heat, or other energy by molecules.  The absorbed energy is converted into heat; Absorption in chemistry is the taking up of one substance by another. For example, a gas such as oxygen may be absorbed, or dissolved, in water.  In the HVAC industry we absorb heat energy from the medium being cooled and transfer that energy in the refrigerant.

Absorption and Adsorption:  In addition to differences in boiling points, each type of hydrocarbon and impurity may have a preferred attraction to another substance or chemical.  Two processes, adsorption and absorption, take advantage of this attraction and are used to separate the various parts of fossil fuels and in particular natural gas.  Adsorption is the sticking or adhesion of liquids or gases to the surface of a solid or another liquid, similar to gum on a wall; where absorption is the taking up or surrounding of a substance by another substance, similar to how a sponge soaks up liquids and holds it within little pockets.  The transfer of molecules of gas or liquid from the outside to the interior of another material.

Absorption Cycle:  Absorption chillers differ from mechanical vapor compression chillers in that they utilize a thermal or chemical process to produce the refrigeration effect necessary to provide chilled water.  There is no mechanical compression of the refrigerant taking place within the machine as occurs within more traditional vapor compression type chillers.  Most commercial absorption chillers utilize lithium bromide (a salt) and water as the fluid pair.

Absorption Factor:  For solar radiation the fraction of solar radiation, transmitted through a glazing system that is absorbed inside the building.

A/C:  An abbreviation for air conditioner or air conditioning.
AC:  Abbreviation for alternating current, a type of electric current in which the polarity is constantly reversing causing the electron flow to reverse.  ACRONYM – An electrical current that periodically reverses its direction.  Standard in US and Canada is 60 cycles per second.  Europe and other countries is 50 cycles per second.  Alternating current.
AC or DC:  Abbreviation for equipment capable of operating on alternating or direct current.

A/C Air Filter (s):  A device which removes solid particulates such as dust, pollen, mold, and bacteria from air. Air filters are used in application where air quality is important, notably in building ventilation systems and in engines, such as internal combustion engines, gas compressors, diving air compressors, gas turbines and others.  Some buildings, as well as aircraft and other man-made environments (e.g., satellites and space shuttles) use foam, pleated paper, or spun fiberglass filter elements. Another method uses fibers or elements with a static electric charge, which attract dust particles. The air intakes of internal combustion engines and compressors tend to use either paper, foam, or cotton filters. Oil bath filters have fallen out of favor. The technology of air intake filters of gas turbines has improved significantly in recent years, due to improvements in the aerodynamics and fluid-dynamics of the air-compressor part of the Gas Turbines.

Acapella: See mucus clearing device.
ACCA:  Air Conditioning Contractors of America.

Acceleration Loss:  The velocity pressure required to accelerate the air from rest to the duct velocity or slot velocity, whichever is higher.

Accelerator:  Any material added to stucco, plaster or mortar which speeds up the natural set.

Accent Lighting:  Accent lighting illuminates walls, reduces brightness and contrast between walls and ceilings or windows.

Acceptable Daily Intake (ADI):  The highest daily amount of a substance that may be consumed over a lifetime without adverse effects.

Acceptable Indoor Air Quality:  Air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction.

Acceptance Test:  A test made upon completion of fabrication, installation, repair, or modification of a system unit, component or part to verify to the user or owner that the item meets specified requirements.

Accepted:  Tested and certified by procedures stipulated by the authority having jurisdiction; refer to CSA Z94.4 for complete details.

Accepted Respirator:  A respirator tested and certified by procedures established by testing and certification agencies recognized by the authority having jurisdiction.

Access Panel:  An opening in the wall or ceiling near the fixture that allows access for servicing the plumbing/electrical system.

Accessible:  Can be approached or entered by the inspector safely, without difficulty, fear or danger.

A/C Circuit:  Alternating Current.  The flow of current through a conductor first in one direction, then in reverse.  It is used exclusively in residential and commercial wiring because it provides greater flexibility in voltage selection and simplicity of equipment design.

A/C Condenser:  The outside fan unit of the air conditioning system.  It removes the heat from the Freon gas and turns the gas back into a liquid and pumps the liquid back to the coil in the furnace.

Accredited Laboratory:  A laboratory having a certificate of accreditation meeting the requirements of ISO/IEC Guide 25 (or other equivalent standard, such as CSA Standard CAN/CSA-Z753) or accreditation by the Standards Council of Canada.

Accumeter:  The metering (flow control) device inside a Carrier centrifugal chiller.  Its unique design always feeds the cooler with liquid refrigerant, which has a much greater cooling capability than a gaseous refrigerant.

Accumulator:  A shell device installed in the suction line of a HVAC system to prevent liquids from entering the compressor.

Accuracy:  Closeness of the result of a measurement to the true value of the quantity measured.

Accurator:  A piston type metering device that feeds the proper amount of liquid refrigerant into the evaporator.

A/C Disconnect:  The main electrical ON-OFF switch near the A/C condenser.

ACE:  See “Air Change Effectiveness.”

Acetone:  A colorless, volatile, extremely flammable liquid ketone, CH3COCH3, widely used as an organic solvent.

A/C Filter (s):  A device which removes solid particulates such as dust, pollen, mold, and bacteria from air. Air filters are used in application where air quality is important, notably in building ventilation systems and in engines, such as internal combustion engines, gas compressors, diving air compressors, gas turbines and others.  Some buildings, as well as aircraft and other man-made environments (e.g., satellites and space shuttles) use foam, pleated paper, or spun fiberglass filter elements. Another method uses fibers or elements with a static electric charge, which attract dust particles. The air intakes of internal combustion engines and compressors tend to use either paper, foam, or cotton filters. Oil bath filters have fallen out of favor. The technology of air intake filters of gas turbines has improved significantly in recent years, due to improvements in the aerodynamics and fluid-dynamics of the air-compressor part of the Gas Turbines.

A/C Filter Replacement:  Generally every 2 - 3 months, but you may want to change them more often. During periods where you are using your HVAC system continuously, we recommend changing monthly to maintain the best indoor air quality. The following chart should assist you:

"The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace your air filters[...] air conditioner furnace filters may need more frequent attention if the air conditioner is in constant use, is subjected to dusty conditions, or you have fur-bearing pets in the house." - United States Department of Energy

A/C Filter Sizes:  Filter Size:  The size of a filter is listed by its length, height and thickness.  For example, a common filter size would be listed as 20x20x1.  20 inches wide by 20 inches high and 1 inch thick.  Nordic Pure has manufactured filters in the following sizes since 1960:
1 inch Air Filters:
10x20x1, 12x12x1, 12x18x1, 12x20x1, 12x24x1, 14x20x1, 14x24x1, 14x25x1, 14x30x1, 15x20x1, 16x16x1, 16x20x1, 16x24x1, 16x25x1, 18x18x1, 18x20x1, 18x24x1, 18x25x1, 20x20x1, 20x24x1, 20x25x1, 20x30x1, 24x24x1, 24x30x1, 25x25x1

2 inch Air Filters:
10x20x2, 12x20x2, 12x24x2, 14x20x2, 14x24x2, 14x25x2, 15x20x2, 16x16x2, 16x20x2, 16x24x2, 16x25x2, 18x18x2, 18x20x2, 18x24x2, 18x25x2, 20x20x2, 20x24x2, 20x25x2, 20x30x2, 24x24x2, 24x30x2, 25x25x2
4 inch Air Filters:
12x24x4, 16x20x4, 16x25x4, 18x24x4, 20x20x4, 20x24x4, 20x25x4, 24x24x4
Now we also carry 5 inch Honeywell Replacements: 16x25x5 and 20x25x5
1 inch Air Filters:
10 x 20 x 1, 12 x 12 x 1, 12 x 18 x 1, 12 x 20 x 1, 12 x 24 x 1, 14 x 20 x 1, 14 x 24 x 1, 14 x 25 x 1, 14 x 30 x 1, 15 x 20 x 1, 16 x 16 x 1, 16 x 20 x 1, 16 x 24 x 1, 16 x 25 x 1, 18 x 18 x 1, 18 x 20 x 1, 18 x 24 x 1, 18 x 25 x 1, 20 x 20 x 1, 20 x 24 x 1, 20 x 25 x 1, 20 x 30 x 1, 24 x 24 x 1, 24 x 30 x 1, 25 x 25 x 1

2 inch Air Filters:
10 x 20 x 2, 12 x 20 x 2, 12 x 24 x 2, 14 x 20 x 2, 14 x 24 x 2, 14 x 25 x 2, 15 x 20 x 2, 16 x 16 x 2, 16 x 20 x 2, 16 x 24 x 2, 16 x 25 x 2, 18 x 18 x 2, 18 x 20 x 2, 18 x 24 x 2, 18 x 25 x 2, 20 x 20 x 2, 20 x 24 x 2, 20 x 25 x 2, 20 x 30 x 2, 24 x 24 x 2, 24 x 30 x 2, 25 x 25 x 2
4 inch Air Filters:
12 x 24 x 4, 16 x 20 x 4, 16 x 25 x 4, 18 x 24 x 4, 20 x 20 x 4, 20 x 24 x 4, 20 x 25 x 4, 24 x 24 x 4
5 inch Honeywell Replacements:
16 x 25 x 5 and 20 x 25 x 5

ACFM:  ACRONYM – Actual Cubic Feet per Minute of gas volume at the actual conditions of temperature, pressure, moisture, elevation and gas composition.  See gas flow rate.

A/C Furnace Filter (s):  Air filters come in a variety of sizes and types. The primary distinction between one filter and another is the size of the filter (length, width and thickness) and the filter material or “media” that is used in the manufacture of the filter. Nordic Pure features all of the popular sizes of air filters. Nordic can also make a filter for your system if we do not stock your size. All custom filters can be ready to ship to you within ten days to two weeks and usually costs about the same as many of our competitor’s ready-made filters.  The air in a furnace or air conditioning system first enters the home through the air return where it passes through the air filter(s) and into the air handler, over the cooling coils or heat exchanger part of the HVAC system (where the air is either cooled or heated) and out through the ductwork into the home. The circulation throughout the HVAC system is accomplished through a powerful blower system (shown above). Because the air filter is the only device in the entire HVAC system capable of removing airborne impurities, it makes sense that frequent replacement of the air filter as well as careful consideration as to the type of air filter you use will directly impact the quality of your indoor air. Conversely, ignoring the HVAC systems air filter means you are allowing the entry of polluted air into the entire system, driving down operating efficiency, filling up ductwork with all dust, pollen, dust mites, etc. and other airborne pollutants while exposing the building’s inhabitants to polluted air. Though there are a wide variety of air filters, they are generally termed as disposable air filters or reusable air filters.  Reusable air filters sound good, in concept. After all, replacement costs can add up over time. The problem is that reusable air filters do not do as an efficient job as desired. To begin, reusable air filters are messy when removed from the HVAC system. Then there is the problem of finding a suitable area to clean the filters. Very often, highly toxic cleaners are required for adequate cleaning of reusable air filters. Once the chemical is used on the filter, it is absorbed into the filter and therefore a certain amount of the cleaner can be released back into the circulating air posing a potential health threat. Nordic does not endorse this type of filter and does not sell reusable filters.
Make-Your-Own Air Filters are designed to enable you to construct your own filter. Buyers for these types of media filters usually do so because their HVAC system does not accommodate standard sized air filters. The most common media for filtration is fiberglass. The handling of fiberglass is difficult as fibers from fiberglass can break off in the skin causing discomfort. Further, fiberglass provides only marginal filter effectiveness. Also, the make-your-own-filters often have no frames to use in securing the media material. As a consequence, the filters can often collapse necessitating a service call by an air conditioning professional. Nordic does not endorse the use of this type of filters. Our many years of manufacturing expertise has enabled us to manufacture a custom filter at about the same price as off-the-shelf air filters from competitors. The most significant difference is that the media material is much higher in quality and has a frame around the material and the media is attached to the frame with a support material insuring there are no collapsed filters.  Disposable panel air filters are the most commonly used type of air filter in furnaces, air conditioning systems or HVAC systems. Panel air filters, being disposable, solve the problems associated with handling dirty filters while insuring ease of removal/replacement. Disposable panel air filters use a variety of media for filtration. A “panel” air filter gets its name because the air filter is actually manufactured as a self-contained, one-piece “panel” that consists of the (a.) air filter media material, (b.) any internal structure that supports the air filter media material such as metal fabric, wire or even cardboard, and (c.) the box or frame in which the air filter media material and the media support material is attached to and housed within. The box or frame of a disposable panel air filter is rigid. The frame is normally constructed of cardboard, plastic or even metal and made to withstand the insertion of the filter into the HVAC system and keep its structural integrity while the HVAC system is operating.  The frame is defined by the length, width and thickness of the box housing the filter media.  The most common type of air filters on the market is panel air filters that use fiberglass as the filter media. Fiberglass filters are very cheap and do an effective job at removing only the largest of airborne particulates. In addition to its limited ability to filter finer particulate, fiberglass is very brittle and can cause harm when handled. Further, there is a potential for the fiberglass fibers to break off and enter passing air creating a serious health problem. Nordic does not endorse the use of fiberglass filters, both because of their limited ability to filter the air, especially smaller particulate and the health implications.  Pleated air filters are much like disposable panel air filters in that the filter media is housed in a rigid panel but the difference is that the media material used to filter the air, as well as the way the material is mounted into the air filter box or frame is different. The filter media used in pleated filters most often resembles fabric and has the capability of removing significantly smaller particulate from the air. Further, when the filter media is integrated into the filter, it is pleated to provide more surface area for filtration. This pleating adds more than double the surface area of un-pleated filters. The net effect is that you end up with a filter that removes more of the particulate in the passing air AND has at least twice as much surface area. Combined, pleated air filters provide a significantly higher level of filtration.  Electrostatic pleated air filters are a more highly evolved version of the pleated air filter. In addition to a higher quality media filter material and pleats for increased surface area for filtration, electrostatic pleated air filters are also electrostatic meaning that the filter media material is electrically charged so that the media material acts much like a magnet to draw more particulate into the media filter material for more efficient filtration. Another benefit of the electrostatic material is that it does not permit the growth of bacteria, often a problem with other filters. Nordic manufactures and sells only Electrostatic Pleated Air Filters in a wide variety of lengths and widths with thickness from 1" to 5".

ACGIH:  American Conference of Government Industrial Hygienists: a professional organization of industrial hygienists who work either in government or academe.  It publishes, does educational work, and sets various health standards, such as TLVs.  See TLV.  An organization that annually determines standards of exposure to toxic and otherwise harmful materials in the workroom air, commonly known as threshold limit value (TLV).  The American Conference of Governmental Industrial Hygienists is a professional society devoted to the development of administrative and technical aspects of worker health protection.  Membership is limited to professional personnel in governmental agencies or educational institutions engaged in occupational safety and health problems.  The ACGIH issues guidelines and recommendations in the form of Threshold Limit Values (TLVs) which are published annually.

ACH, Air Changes per Hour:  Air changes per hour.  The number of times that air in a house is completely replaced with outdoor air in one hour.
Acid:  Any chemical with a low pH that in water solution can burn the skin or eyes.  Acids turn litmus paper red and have pH values of 0 to 6.

Acid Aerosol:  Acidic liquid or solid particles that are small enough to become airborne.  High concentrations of acid aerosols can be irritating to the lungs and have been associated with some respiratory diseases, such as asthma.

Acid Deposition:  A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either wet or dry form.  The wet forms, popularly called “acid rain,” can fall to earth as rain, snow, or fog.  The dry forms are acidic gases or particulates.  A comprehensive term for the various ways acidic compounds precipitate from the atmosphere and deposit onto surfaces.  It can include:  (1.) wet deposition by means of acid rain, fog, and snow; and (2.) dry deposition of acidic particles (aerosols).

Acid Etch:  A preparatory step for concrete sealing.  Diluted hydrochloric acid is applied to the concrete to etch the surface for better seal adhesion.

Acid Gases:  Gases which are acids, or produce acids when in contact with moisture.

Acid Rain:  A broad term used to describe several ways that acids fall out of the atmosphere.  A more precise term is acid deposition, which has two parts: wet and dry. Wet deposition refers to acidic rain, fog, and snow.  Dry deposition refers to acidic gases and particles.  Acid rain is primarily caused by the reaction of two common air pollutants, sulphur dioxide and nitrogen oxides, with water in the atmosphere.  A term used to describe several ways that acidic compounds fall out of the atmosphere, causing a variety of ground-level environmental effects.  These effects include damage to forests and soils, fish and other living things, and human health.  Acid rain also reduces how clearly we can see through the air, an effect called visibility reduction.  In the United States, about two-thirds of all sulfur dioxide and one-quarter of all nitrogen oxides come from electric power generation that relies on burning fossil fuels like coal.  Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds.  These acidic compounds fall to the earth as acidic rain, fog, and snow, or as dry deposited gases and particles that can be blown to the ground by the wind.

Acidity:  The quality, state or degree of being acid.  In oils, acidity denotes the presence of acid-type constituents whose concentration is usually defined in terms of neutralization number.

A-Coil:  A heat exchanger consisting of two diagonal coils that are joined together in a manner that looks like the letter “A.”

Acoustical:  Of or pertaining to sound.

ACP:  Association of Contingency Planners.  A national association with local chapters located around the country.

Acre:  43,560 square feet.

Acre Foot (AF):  The amount of water required to cover an acre one foot deep (325,861 gallons).  A family of five uses about one acre-foot of water per year.

AC Replacement:  A quality job begins with quality products. The Sansone Corporation is recognized as an award winning dealer for both Carrier and Trane, the two most popular brand names in America for reliable, efficient air conditioning. Since 1976, Sansone Corporation has been dedicated to carefully matching the comfort needs of residents, with an expanded choice of product innovations from these leading manufacturers, in order to satisfy both your comfort requirements and your budget.  From residential to commercial, there is no job that is too big or too small. If you’re ready for a new air conditioning system, let the courteous, Sansone installation consultants show you how you can start saving money right away and avoid the potentially higher service costs later. 

Four Things to Consider Before Buying a Heating and Cooling System

The following information has been provided by the Carrier website.

1. Efficiency  Efficiency ratings are like gas mileage – the higher the rating, the more efficient the product is. All products are given the following ratings, so you’ll know exactly what to expect from your investment.

SEER
(Seasonal Energy Efficiency Ratio)
This measurement gauges air conditioning cooling. All new models are required to have at least a 10.0 SEER rating. The Infinity 18 air conditioner receives up to 18.0 SEER.

ENERGY STAR®
Carrier Corporation has determined that certain products meet ENERGY STAR® guidelines for energy efficiency. Look for this logo on our Infinity and performance™Series products.  
2. Refrigerant  Freon®–22 Refrigerant
Since its debut in 1930, Freon refrigerant has been used in cooling systems. And while it’s still available, the Clean Air Act of 1990 prohibits the production of Freon–22-based air conditioners and heat pumps by 2010, and Freon–22 production by 2020. As Freon–22 production declines, its cost is predicted to rise. (Freon is a registered trademark of E.I. duPont de Nemours & Company.)
Puron® Refrigerant
Carrier was the first to introduce a new, non-ozone-depleting refrigerant called Puron – a full six years ahead of the competition — paving the way for the future. Puron refrigerant is chlorine-free, so it doesn’t damage the Earth’s ozone layer. And, as other refrigerants become less available, Puron refrigerant will be the refrigerant of choice for years to come.  
3. Comfort
Carrier specializes in creating a customized home comfort system with our broad selection of heating and cooling products. Your Carrier dealer can help you choose the best system for your home including Carrier-exclusive features that further enhance your indoor environment.
ComfortHeat™ Technology
ComfortHeat™ Technology accurately predicts the need for heating while cutting temperature swings in half, and provides a nearly continuous flow of warmth in low-capacity operation for a steadier, more consistent indoor temperature.

Infinity™ System
When a heat pump or air conditioner is combined with a variable-speed furnace or fan coil, the revolutionary Infinity System is the only system in the industry that allows you to control temperature, humidity, air quality, fan speed and ventilation; and even detects when your air filter needs replacing. It’s so advanced it automatically adjusts to your systems’ needs for peak efficiency and performance. It’s the ultimate control center for all of your home system components.
IdealHumidity™ Systems
IdealHumidity Systems automatically add or remove just the right amount of moisture to keep your home comfortable. IdealHumidity Systems can help you save on energy costs, too. When the humidity is right, you can feel comfortable at higher temperatures in the summer, and lower temperatures in the winter.

4. Sound  Carrier air conditioners are also quiet, thanks to the exclusive Silencer System™ that ensures extra-quiet performance by maximizing airflow while minimizing vibration. With sound ratings as low as 69 decibels (dB), Carrier’s Infinity™ Series air conditioners make less noise than a refrigerator.

A/C Replacement Filter (s):  Generally every 2 - 3 months you will want to replace your air filters, but you may want to change them more often. During periods where you are using your HVAC system continuously, we recommend changing monthly to maintain the best indoor air quality. The following chart should assist you:

“The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace your air filters[...] air conditioner furnace filters may need more frequent attention if the air conditioner is in constant use, is subjected to dusty conditions, or you have fur-bearing pets in the house.” - United States Department of Energy
You can turn to Nordic Pure for all of your air conditioner filter replacement needs.  We manufacture an array of standard filter sizes and are able to custom make any size to match your unit. 

Acrolein:  An agent added to methyl chloride to make you aware of refrigerant leaks.

Acrylic:  A glassy thermoplastic material that is vacuum-formed to cast and mold shapes that form the surface of fiberglass bathtubs, whirlpools, shower bases, and shower stalls.  A synthetic polyermized fiber that contains at least 85% acrylonitrile.

Acrylics:  A family of plastics used for fibers, rigid sheets and paints.

Acrylonitrile:  A colorless, volatile, flammable liquid nitrile C3H3N used chiefly in organic synthesis and for polymerization.

ACT:  ACRONYM – Activate, Activation.

Action Level:  A concentration established by environmental protection agencies for a substance in a particular medium (water, soil, etc.) that may present a health risk or affect beneficial uses when exceeded.  If contaminants are found at concentrations above their action levels, measures must be taken to decrease the contamination.  A specific concentration of a toxic substance in the air established by OSHA that when reached makes the performance of certain procedures necessary, e.g., monitoring the air, notifying all employees affected.  (EPA’s current action level is 4 pCi/L.)

Action Packet:  In reference to the IAQ Tools for Schools Action Kit - contains numerous products to assist school personnel to implement an effective yet simple IAQ program in their school.

Action Plan:  A list of specific instructions drawn up by a health care professional for an asthmatic to follow.  The plan includes a normal schedule for asthma medicines, as well as what to do if peak flow readings or asthma symptoms become worse than usual.  These plans are split into zones (red, green, and yellow).  See:  Zones.

Activate:  To turn on, supply power, or enable systems, equipment, or devices to become active by normal operating controls.  Examples include turning on the gas or water supply valves to the fixtures and appliances and activating electrical breakers or fuses.

Activated Alumina:  A type of aluminum oxide that absorbs moisture (used in refrigerant driers).  An adsorption type desiccant.

Activated Carbon / Charcoal:  A form of carbon ‘activated’ by treatment with oxygen to have very high surface area, capable of removing many gases and odors from the air.  Activated Carbon is a specially treated carbon that has been exposed to heat around 800-900 degrees Celsius.  The great thing about activated carbon is that it has a large internal surface area and can trap a lot of impurities inside it.  Activated carbon is most commonly seen in simple tap water filters and fish tank filters, but is also used in some small air filters and has even been used in cigarette butts.

Activated Carbon:  Charcoal activated by heating to 1472-1652ºF a material of high adsorptive gases, vapors, organics, etc.  Has a large internal surface area.  Removes dissolved color, odor and taste from liquids or gases.  Commonly used in the pharmaceutical industry to remove organic contaminants.  A processed carbon used in filter driers, commonly used in air filters to clean the air.

Activated Carbon Filter:  See Gas-phase adsorber cell.  See also Adsorption.  Also see “Activated Charcoal.”

Activated Carbon/Zeolite Blend:  This is a blend of adsorbents used in some air purifiers that removes odors and certain chemicals from the air.

Activated Charcoal:  Activated Charcoal is used to remove odorous substances from air (in vacuum cleaners and air purifiers) and water (in water filters) through adsorption.  Activated charcoal is made by treating charcoal with oxygen, which has the effect of creating countless holes or pathways in the charcoal.  The result is a charcoal with an amazingly large surface area.  As air or water passes through the immense surface area of activated charcoal, odorous compounds are caught in the innumerable bonding sites.  Activated charcoal only removes specific impurities that are attracted to carbon while others will pass right through.  Activated charcoal filters stop working once all the bonding sites are filled with trapped impurities, requiring that the filter be replaced.  Activated charcoal filtration is sometimes referred to as carbon or active carbon filtration.

Activated Military Carbon Cloth:  A cloth impregnated with activated charcoal to remove odors and gasses.

Activated Sludge:  Sludge floc produced in raw or settled wastewater by the growth of zoogleal bacteria and other organisms in the presence of dissolved oxygen.

Active Cooling:  HVAC term for compressor driven air conditioning.

Active Diffuser:  An air supply outlet with a local fan to deliver air from the plenum through the diffuser into the conditioned space.

Active Height Control:  This is a feature of certain SEBO upright vacuums also referred to as Automatic Height Adjustment.  Electronic controls identify the floor and the height of the carpet nap.  The brush is then raised or lowered automatically depending upon the type of carpet or flooring for optimal cleaning performance.

Active HEPA Filter:  This is a Miele trade name for their HEPA (High Efficiency Particulate Air) filter that not only captures and retains tiny, lung-damaging particles (including dust mite feces and pollen), it also includes the same Generally Activated Charcoal filter (GAC) that the Active Air Clean filter uses to absorb odors.  This Miele filter conforms to the new stringent European standard for filtration (EN 1822) which means that it actually traps 99.99% of all particles as tiny as 0.3 of a micron.

Active Solar Techniques:  Mechanisms, such as flat-plate collectors, which are designed to actively collect the energy of sunlight and use it; for example, to heat a building or to heat water.

Active System:  A traditional HVAC system that uses mechanical means to artificially condition (cool, heat, ventilate) the air supply in a building and that draws power for these processes from electricity or gas.

Activity:  Activity is the rate of transformation or decay of a radioactive material.  The SI unit of activity is the reciprocal second (s-1) and its special name is the Becquerel.  Federal and state agencies in the United States use conventional units where activity is given in curies (Ci); 1 Ci = 3.7 x 1010 Bq.

ACTR:  ACRONYM – Actuator.

Actual Capacity:  Quantity of gas actually compressed and delivered to the discharge system at rated speed of the machine and under rated pressure conditions.

Actual Dimension (Lumber):  The exact measurement of lumber after it has been cut, dried and milled.

Actual Size:  The true size of the filter.  See Nominal Size.

Acute:  Sudden.  Brief, not ongoing.  Usually implies relatively high intensity.  Acute asthma symptoms may last a short time but are more severe than an individual’s usual symptoms.
Acute Effect:  Adverse effect on a human or animal which has severe symptoms developing rapidly and coming quickly to a crisis.  Also see “chronic effect.”

Acute Exposure:  A single exposure to a toxic substance which results in biological harm or death; usually characterized as lasting no longer than a day (24 hours).

Acute Health Effect:  Ahealth effect that occurs almost immediately (hours/days) after a single or brief/acute exposure.  The term is used to describe brief exposures and effects which appear promptly after exposure to a toxic agent.

Acute Toxicity:  Relatively short-term lethal or other effect, usually defined as occurring within four days for fish and macroinvertebrates and shorter times (two days) for organisms with shorter life spans.  The ability of a substance to cause poisonous effects resulting in severe biological harm or death soon after a single exposure or dose.  Any severe poisonous effect resulting from a short-term exposure.

AC Vent Filter (s):  Air Register Vent Filters are made of a self-charging electrostatic material that acts as a dust magnet for your vent register system.  Use them in bathrooms, bedrooms, kitchen, family room and RV/Motor Homes.  When air flows through the filter, dirt, dust, smoke, and pollen sized particles are trapped. Filtered air then passes back into your house.  Keeps dirt and objects from falling into ducts.  Air Vent Filters are designed to provide filtered air in your home.

Ad Hoc:  An ad hoc committee is one that is set up for a particular purpose.

Adaptive Model (Adaptive Approach):  For thermal comfort this is an approach to the study of thermal comfort starting from the observation that there are a range of actions which occupants can take to achieve thermal comfort, and that discomfort is caused by constraints imposed on the range of actions by social, physical or other factors (see also Adaptive Principle).  Over time this means that people are comfortable at the ‘usual’ or ‘average’ temperature which they experience.

Adaptive Opportunity:For thermal comfort:  the ability of a building to allow adaptation to broaden the band of temperatures at which the person could be comfortable.  Actions might include adding or removing a layer of clothing, changing posture, or adjusting the metabolic rate.  Spatial variation of temperature across the room, availability of a desk fan, and the presence of sun shading or openable windows would make the adaptive opportunities still greater.  These actions either alter the temperature which is required for comfort, or alter the room temperature towards that which the occupants will find comfortable.

Adaptive Principle: A principle which can be stated as: If a change occurs (in the thermal environment) such as to produce discomfort, people
react in ways which tend to restore their comfort.

Adaptive Processes:  The range of actions that man takes to achieve thermal comfort.

Adaptive Reuse:  Renovation of a building or site to include elements that allow a particular use or uses to occupy a space that originally was intended for a different use.

Adaptor:  A fitting that unites different types of pipe together, e.g. ABS to cast iron pipe.

Additive:  An additive is something that is added to a product, but which does not affect the product’s performance.  For instance, adding color to a Popsicle doesn’t change the Popsicle’s taste; therefore, color is an additive.  For those with allergies, additives can be a real problem.  Things like artificial color, dyes, fragrances, and preservatives are all potential allergens.

Add-on Control Device:  An air pollution control device such as carbon absorber or incinerator that reduces the pollution in exhaust gas.  The control device usually does not affect the process being controlled and thus is “add-on” technology, as opposed to a scheme to control pollution through altering the basic process itself.  See also pollution prevention.

Adenoidectomy:  Pronunciation (ad′ĕ-noy-dek′tŏ-mē).  An operation for the removal of adenoid tissue from the nasopharynx.

Adenoids:  Pronunciation (ad′ĕ-noydz).  Adenoids (or pharyngeal tonsils, or nasopharyngeal tonsils) are a mass of lymphoid tissue situated at the very back of the nose, in the roof of the nasopharynx, where the nose blends into the mouth.  Normally, in children, they make a soft mound in the roof and posterior wall of the nasopharynx, just above and behind the uvula.
Adenoids are part of the immune system. Like all lymph tissue, they trap infectious agents like viruses and bacteria, and they produce antibodies.  Since the adenoids are located at the back of the nasal airway, they provide defense against inhaled substances.  This function decreases with age as the adenoids shrink. Because adenoids do ordinarily shrink by late childhood, the problems caused by enlarged adenoids rarely occur in adults.

Adhesion:  Molecular attraction that holds the surfaces of two substances in contact.  The property of a coating or sealant to bond to the surface to which it is applied.

Adhesive Failure:  Loss of bond of a coating or sealant from the surface to which it is applied.

Adiabatic:  A change in gas condition where no heat is added or removed except in the form of work.

Adiabatic Compression:  A type of compression where no heat is transferred to or from the gas during the compression process.

Adiabatic Efficiency:  Ratio between measured shaft power and the adiabatic compression power, referring to measured mass flow.

Adjudication:  A determination of water rights for an entire stream or ground water basin.  Adjudication sets priorities of rights during shortages.

Administrative Control Measures:  Methods of controlling worker exposure to dangerous substances by limiting contact time with the substance.

Adrenalectomy:  Surgical removal of the adrenal glands.

Adrenergic:  Resembling some of the effects of adrenaline.  Medications called beta-adrenergic drugs are commonly used in asthma to help open up the airways (which is why they are called bronchodilators).

Adsorb:  A method causing a liquid or gas to condense on the surface only of an adsorbing material.

Adsorbent:  In addition to the adjectival meaning, the term describes any of several substances that collect gaseous pollutants.  Used both for measurement and control.

Adsorbent Filter:  A filter medium primarily intended to hold soluble and insoluble contaminants on its surface by molecular adhesion.

Adsorber:  A device for removing gases or vapors from air by means of preferential physical condensation and retention of molecules on a solid surface.  Adsorbers used in nuclear applications are often impregnated with chemicals to increase their activity for organic radioactive iodine compounds.

Adsorber Cell:  A modular replaceable adsorber element.
Adsorption:  Adhesion of a thin layer of molecules to a surface they contact.  Adhesion of molecules of liquids, gases, and dissolved substances to surfaces of solids; as opposed to absorption, taking of molecules of one substance directly into another substance.  Adsorption is a surface phenomenon; absorption is an intermingling or interpenetration of two substances.  Removal of a pollutant from air or water by collecting the pollutant on the surface of a solid material; e.g., an advanced method of treating waste in which activated carbon removes organic matter from waste-water.  Adsorption is often used to extract pollutants by causing them to be attached to such adsorbents as activated carbon or silica gel.

Adsorptive Filtration:  The attraction to, and retention of particles in, a filter medium by electrostatic forces, or by molecular attraction between the particles and the medium.

Advance Directives:  Legal documents including the Living Will and Durable Power of Attorney for Health Care.  A Living Will states what type of treatment you wish to receive in the event that you become physically or mentally unable to communicate your wishes.  A Durable Power of Attorney for Health Care authorizes another person to make medical decisions for you when you are unable to do so for yourself.  See also Living Will and Durable Power of Attorney for Health Care.

Advanced Reciprocating Compressor:  Type of compressor that uses a more efficient process for compressing refrigerant for better cooling efficiency.

Advanced Treatment:  A level of wastewater treatment more stringent than secondary treatment; requires an 85% reduction in conventional pollutant concentration or a significant reduction in non-conventional pollutants.  Sometimes called tertiary treatment.

Adverse:  Undesirable.

Adverse Health Effect (Occurrence):  Any abnormal, harmful, or undesirable effect (occurrence) on the physical, biochemical, biological, or behavioral well-being of a person that results from being exposed to pollutants in the environment.  A health effect from exposure to air contaminants that may range from relatively mild temporary conditions, such as eye or throat irritation, shortness of breath, or headaches to permanent and serious conditions, such as birth defects, cancer or damage to lungs, nerves, liver, heart or other organs.

Adversely Affect:  Constitute, or potentially constitute, a negative or destructive impact.

Advisory Level:  The level above which an environmental protection agency suggests it is potentially harmful to be exposed to a contaminant, although no action is mandated.

AEE (Association of Energy Engineers):  A trade organization for certification and information on energy efficiency, utility deregulation, facility management, plant engineering, and environmental compliance.

Aerated Pond (see Oxidation Pond):  A natural or artificial wastewater treatment pond in which mechanical or diffused-air aeration is used to supplement the oxygen supply.

Aeration:  Act of combining substance with air.  Passing air through a solid or liquid, especially a process promoting breakdown or movement of contaminants in soil or water by exposing them to air.  To combine or charge with gas.  Exposing water to the air; often results in the release into the atmosphere of gaseous impurities found in polluted water.

Aerator:  An apparatus that mixes air into flowing water.  It is screwed onto the end of a faucet spout to help reduce splashing.

Aerobic:  In the presence of oxygen.

Aerobic Bacteria:  Organisms which require oxygen to live.

Aerobic Treatment:  Process by which microbes decompose complex organic compounds in the presence of oxygen and use the liberated energy for reproduction and growth.

Aerodynamic Diameter:  The diameter of a unit density sphere having the same settling velocity in air as the particle in question of whatever shape and density.

Aerosol:  Aerosol is the term used to describe the dispersing of tiny particles of liquid in a volume of air approximately 100µ or smaller in size.  Example: dust, smoke, fog.  Aerosol sprays tend to be highly flammable and most often come as pressurized canisters.  (1.) Small droplets or particles suspended in the atmosphere, typically containing sulfur.  They are usually emitted naturally (e.g. in volcanic eruptions) and as the result of anthropogenic (human) activities such as burning fossil fuels.  (2.) The pressurized gas used to propel substances out of a container.  Particles of solid or liquid matter that can remain suspended in air from a few minutes to many months depending on the particle size and weight.

Aerosol Generator:  A device, used in conjunction with an aerosol photometer, which creates a polydispersed sub-micron aerosol to challenge integrity of HEPA filters and containment of safety cabinets.

Aerosol Photometer:  A device used to determine particle size and distribution in air by measuring the mass concentration of scattered light.

Aerosol Spectrometer:  A device used to determine particle size and distribution in air by measuring the range of color produced by passing a white light through a prism.

Aesthetically:  Tastefully; concerned with appearance.

Af:  Fan wheel design with airfoil-shaped blades.

AFCOM:  Association For Computer Operations Managers.  A national trade association.  AFCOM publishes a bi-monthly magazine The Computer Operations Manager.  (www.afcom.com/).

Affluent:  Fluid entering the filter or filter system.  Commonly described as influent, it is the opposite of effluent.

Afterburner:  In incinerator technology, a burner located so that the combustion gases are made to pass through its flame in order to remove smoke and odors.  It may be attached to or be separated from the incinerator proper.  An air pollution abatement device that removes undesirable organic gases through incineration.

Aftercooler:  Heat exchangers for cooling air or gas discharge from compressors.  Designed to reduce the temperature and liquefy condensate vapors.  Both air cooled and water cooled units are available.

Aftercooling:  The removal of heat from a gas after compression is completed.

After-treatment Device:  Engine pollutant emissions are generally reduced by engine modifications, fuel specifications or exhaust gas after treatment.  An after-treatment device is a component used to reduce engine pollutant emissions downstream of the combustion chamber.  Catalytic converters and particulate traps are examples of after-treatment devices.

AFUE – Annual Fuel Utilization Efficiency:  The ratio of annual output of useful energy or heat to the annual energy input to the furnace.  This is a measurement of the efficiency of a gas furnace.  The higher this rating is the more efficient the furnace will be.  It describes the percentage of heat produced for every dollar of fuel consumed.  Indicated as a percentage, your furnace’s AFUE tells you how much energy is being converted to heat.  For example, an AFUE of 90 means that 90% of the fuel is being used to warm your home, while the other 10% escapes as exhaust with the combustion gases.  The minimum percentage established by the DOE for furnaces is 78%.

AGA:  Abbreviation for American Gas Association, Inc.

Agenda 21:  A comprehensive blueprint for global action drafted by the 172 governments present at the 1992 Earth Summit organized by the United Nations in Rio de Janeiro, Brazil.

Agent:  Any biological, chemical or physical power, principle or substance capable of acting upon a subject organism, usually to its detriment.

Agglomerating Dust:  Dust particles that exhibit tendencies for particle growth, such as powdered milk, fertilizer, detergents, etc.

Agglomeration, Particle:  Multiple particles joining or clustering together by surface tension to form large particles, usually held by moisture, static charge or particle architecture.

Aggregate:  Crushed stone, slag or water-worn gravel that comes in a wide range of sizes which is used to surface built-up roofs.

Agitation:  In terms of vacuum cleaners, agitation is the brushing action on carpet fibers.  This can be from the fixed brush on a carpet and rug tool or from the revolving brush of a turbine or motorized power head.  Agitation is important in order to break surface tension to release fine soils as well as to remove more difficult surface soils such as pet hair.  Revolving brushes sometimes use “beater bars” to bring fine soils and dust up from carpet backing for removal.

Agonist:  When talking about drugs, this refers to a compound that stimulates or enhances activity of the cell receptors.

Agricultural Bi-products:  Products developed in agriculture but are not primary products.  These are often converted into building materials, such as straw used in wall panels or entire bales used as building blocks.

Agricultural Burning:  The intentional use of fire for vegetation management in areas such as agricultural fields, orchards, rangelands, and forests.  The regulation of agricultural burning is described in the Agricultural Burning Guidelines, Title 17, California Code of Regulations.

Agricultural Fibers:  Natural fibers, such as cotton, often used as insulation materials. <

Agricultural Residue:  Plant parts, primarily stalks and leaves, not removed from the fields with the primary food or fiber product.  Examples include corn stover (stalks, leaves, husks, and cobs); wheat straw; and rice straw.

AHAM:  An acronym for the American Home Appliance Manufacturers trade group, a company that tests and certifies air purifiers based on CADR (Clean Air Delivery Rate).  See “CADR.”

AHU (Air Handling Unit):  Equipment that includes a fan or blower, heating and/or cooling coils, regulator controls, condensate drain pans, and air filters.  An air handler, or air handling unit and often abbreviated to AHU, is a device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system. Usually, an air handler is a large metal box containing a blower, heating and/or cooling elements, filter racks or chambers, sound attenuators, and dampers. Air handlers usually connect to ductwork that distributes the conditioned air through the building, and returns it to the AHU. Sometimes AHUs discharge (supply) and admit (return) air directly to and from the space served, without ductwork.  Small air handlers, for local use, are called terminal units, and may only include an air filter, coil, and blower; these simple terminal units are called blower coils or fan coil units. A larger air handler that conditions 100% outside air, and no recirculated air, is known as a makeup air unit (MAU). An air handler designed for outdoor use, typically on roofs, is known as a rooftop unit (RTU).

AHU Filters:  Air filtration is almost always present in order to provide clean dust-free air to the building occupants.  It may be via simple low-MERV pleated media, HEPA, electrostatic, or a combination of techniques.  Gas-phase and ultraviolet air treatments may be employed as well.   It is typically placed first in the AHU in order to keep all its components clean.

AIA:  American Institute of Architects.

AIHA:  American Industrial Hygiene Association.

Air:  A colorless, odorless, tasteless gas.  A mixture of individual gases.  The gaseous mixture surrounding the earth.  Standard density of dry air free of carbon dioxide (0°C, 101,325 kPa) is equal to 1,292 8 g/L.  Standard conditions for air in spectroscopy are 101,325 kPa, 15°C, 0.03% CO2, dry.  A mixture of gasses constituting a compressed fluid tied to the planet by gravitational attraction.  Air is 79.0% nitrogen, 20.9% oxygen, and less than 0.1% a mixture of carbon dioxide, argon, helium, and hundreds of other gasses originating from natural and man-made sources.  So called “pure” air is a mixture of gases containing about 78 percent nitrogen; 21 percent oxygen; less than 1 percent of carbon dioxide, argon, and other gases; and varying amounts of water vapor.  See also ambient air.

Air Actuator:  An elastomeric bellow with specially designed metal end closures used in place of pneumatic or hydraulic cylinders.  A device which induces action or motion with compressed air being the medium through which the power is transmitted.

Air Amplifier:  A component on a compressed air line designed to increase in magnitude the flow by releasing small amounts of compressed air at high velocity through an internal, ring shaped nozzle.  This column of air released through the front creates a vacuum behind, thus pulling ambient air through the rear and pushing ambient air in front.

Air Balance:  HVAC term for distributing air through a system to precisely match the required amount.  Meaning, as it applies to Class II cabinets, to adjust airflow volume so that air exhaust is equal to air intake and thereby eliminating (or minimizing) movement of outside air into the cabinet work area and vice versa through the face opening.

Air Barrier:  Any part of the building shell that offers resistance to air leakage.  The air barrier is effective if it stops most air leakage.  The primary air barrier is the most effective of a series of air barriers.  For buildings a material carefully installed within a building envelope assembly to minimize the uncontrolled passage of air into and out of a dwelling.  Induction of room air through the front opening of safety cabinets that contain hazardous aerosols.  The unidirectional movement of air past and parallel to the plane of an opening, and at a velocity greater than that on either side, thereby creating an impedance to transverse movement of airborne particulates through the opening.  Air barriers are systems of materials designed and constructed to control air flow between a conditioned space and an unconditioned space. The air barrier system is the primary air enclosure boundary that separates indoor (conditioned) air and outdoor (unconditioned) air. In multi-unit/townhouse/apartment construction the air barrier system also separates the conditioned air from any given unit and adjacent units. Air barrier systems also typically define the location of the pressure boundary of the building location. In multi-unit/townhouse/apartment construction the air barrier system is also the fire barrier and smoke barrier in inter-unit separations. In such assemblies the air barrier system must also meet the specific fire resistance rating requirement for the given separation.  Air barrier systems are assembled from “materials” incorporated in “assemblies” that are interconnected to create “enclosures.” Each of these three elements has measurable resistance to air flow. The minimum resistance or air permeances for the three components are:
Material       0.02 l/(s-m2)@ 75 Pa
Assembly   0.20 l/(s-m2)@ 75 Pa
Enclosure   2.00 l/(s-m2)@ 75 Pa

• Material:  0.02 l/(s-m2) @ 75 Pa
• Assembly: 0.20 l/(s-m2) @ 75 Pa
• Enclosure: 2.00 l/(s-m2) @ 75 Pa

Air Basin:  A land area with generally similar meteorological and geographic conditions throughout.  To the extent possible, air basin boundaries are defined along political boundary lines and include both the source and receptor areas.  California is currently divided into 15 air basins.

Air Cleaning Stage:  An air cleaning stage is a single component or a bank of identical components in an air cleaning unit or an air cleaning system.  A system that has one bank of components (e.g., HEPA filters) in each of three air cleaning units, arranged in parallel, is a single stage system.  A multistage unit or system has two or more stages in tandem.

Air Cleaning System:  A device or combination of devices applied to reduce the concentration of airborne contaminants, such as microorganisms, dusts, fumes, respirable particles, other particulate matter, gases, and/or vapors in air.  An IAQ control strategy to remove various airborne particulates and/or gases from the air.  The three types of air cleaning most commonly used are particulate filtration, electrostatic precipitation, and gas sorption.

Air Cleaning Unit:  An air cleaning unit is an assembly of components, which comprises a single division of a complete air cleaning system, including all components necessary to perform the air cleaning function of that subdivision.

Air Cleanup System:  A system provided to decontaminate the air in, or exhausted from, a contained space following a system upset or prior to personnel access to the contained space.

Air Coil:  Coil on some types of heat pumps used either as an evaporator or condenser.

Air Conditioner:  An appliance used for cooling, humidifying, dehumidifying or any other air treatment.  Assembly of equipment for the simultaneous control of air temperature, relative humidity, purity, and motion.  A term often applied to comfort cooling equipment.

Air Conditioner Air Flow:  Air conditioning units in your home have to be properly sized to fit your home. Your heating and AC contractor (HVAC) figures out how many supply ducts and return air ducts need to be in each room for the best air flow.

Air Conditioning:  A process that maintains comfort conditions in a defined area.Control of the indoor environment by controlling the thermal characteristics (cleaning, changing the water content but mainly heating and cooling) the air supplied to the room.  To condition air, transfer of heat and humidity from one medium to another.  A process that maintains comfort conditions in a defined area.The process of treating air to meet the requirements of a conditioned space by controlling its temperature, humidity, cleanliness, and distribution.

Air Conditioning Coils:  See cooling coils.

Air-Conditioning and Refrigeration Institute (ARI):  ARI is an industry trade association that develops standards for measuring and certifying product performance.  For instance, ARI Standard 270 provides guidelines for establishing sound levels for outdoor air-conditioning equipment.

Air Conditioning Filter Smoke:  An air conditioner/furnace filter can only do part of the job you need to purify the air in your house.  An electrostatic furnace filter is not the most effective product for smoke removal either. It will not impact dust mites or cat allergies, for which you need a room HEPA filter.

Air Consumption:  The volume of air required to operate a pneumatic device.

Air Contaminant:  An impurity emitted to the outside air.  It can be solid, (dust, particulate matter), liquid (vapor, mist) or gas (carbon monoxide, sulfur dioxide).

Air Cooled:  Uses a fan to discharge heat from the condenser coil to the outdoors.

Air Cooled Compressor:  A compressor cooled by atmospheric air circulated around the cylinders or casing.

Air-Cooled Condenser:  Heat of compression, plus the heat of absorption, is transferred from refrigerant within coil to surrounding air, either by convection or fan or blower.

Air-Cooled System:  A type of air conditioning system that uses Freon as a refrigerant and air as a condensing medium.  Typically, the air-cooled condenser is located outside and refrigerant lines are piped to it from the indoor unit.

Air Cooler:  Mechanism designed to lower temperature of air passing through it.

Air Curtain:  A component on a compressed air line that provides wide area coverage with a thin sheet of air.  Also amplifies compressed air flow, reduces noise.  Used in blowing, cooling.  Also known as air knife.  Mechanical air-moving device designed to limit the in-flux of unwanted air at a building opening.

Air Cylinder:  A component made up of a cylinder barrel, end covers, a piston rod, a steel or stainless steel piston.  A device which induces action or motion with compressed air being the medium through which the power is transmitted.

Air Diffuser:  Air distribution outlet or grille designed to direct airflow into desired patterns.  Typically located in the ceiling, which mixes conditioned air with room air.

Air Diffusion:  Distribution of the air in a space, called the treated space, by means of devices, called air terminal devices, in a manner so as to meet certain specified conditions, such as air change rate, pressure, cleanliness, temperature, humidity, air velocity and noise level.

Air Distribution:  The transportation of a specified air flow to or from the treated space or spaces, generally by means of ductwork.

Air District:  A political body responsible for managing air quality on a regional or county basis.  California is currently divided into 35 air districts.  (See also Air Pollution Control District and Air Quality Management District).

Air-dried Lumber:  Lumber that has been piled in yards or sheds for any length of time.  For the United States as a whole, the minimum moisture content of thoroughly air dried lumber is 12 to 15 percent and the average is somewhat higher.  In the South, air dried lumber may be no lower than 19 percent.

Air Dryer:  A device for drying compressed air by means of condensation obtained by over-compression or cooling, absorption, adsorption or a combination of the above methods.

Air Duct:  Ducts, usually made of sheet metal, that carry cooled or heated air to all rooms.

Air Exchange:  The total building air exchanged with the outdoors through air leakage and ventilation.  Also, this term can be used to indicate the rate at which outside air replaces indoor air in a given space but in terms of air purifiers it is typically used to indicate how many times the air volume in a given space will be filtered by an air purifier per a set period of time.

Air Exchange Rate:  The rate at which outside air replaces indoor air in a space.  Expressed in one of two ways:  the number of changes of outside air per unit of time air changes per hour (ACH); or the rate at which a volume of outside air enters per unit of time – cubic feet per minute (cfm).

Air Filter (s):  A device for removing particulate material from an air stream.  An air cleaning device that removes particulate contamination from an air stream by straining, impingement, interception, electrostatic attraction or absorption.  Adhesive filters made of metal or various fibers that are coated with an adhesive liquid to which particles of lint and dust adhere.  These filters will remove as much as 90% of the dirt if they do not become clogged.  The more common filters are of the throwaway or disposable type.

Air Filter Airflow:  High Efficiency Particulate Arresting (HEPA) filters have been around for quite some time.  In the 1950s the US Atomic Energy Commission needed something to remove small particulates that are radioactive. Since then HEPA air purifiers have been using this technology to clean the indoors in cleanrooms to beauty parlors. HEPA products are also one of the many techniques and products used by Allergy and Asthma doctors to help alleviate the symptoms of those conditions. First we will discuss what HEPA really is.  Imagine a filter that only allows very tiny particles to pass through. If we placed a single sheet of this HEPA paper in front of a fan constrained as it would be in air purifiers, very little air would be able to pass because of the small size of the holes. In addition, air purifiers made like this would need to have the filter changed often because the holes would plug rapidly. Now if we double the size of the sheet we would get twice the airflow and filter life. You can not keep growing the sheet larger because it would be impractical. Instead let us try folding the paper back and forth so that we can present a very large surface area to the airflow and thus the HEPA made this way would be efficient. This is how real-world HEPA filters are made in real HEPA systems. Some have as much as 40 square feet of the filter material folded into the HEPA section. As a side note the material from which HEPA is constructed is either fiber or paper-like on one hand or a polymer on the other.  HEPA material does not look like a screen or a colander. Instead it looks like a very thin bail of fibers.  Thus the air has to find a route through this maze of fibers.  There are three ways the HEPA filter stops particulates.  First and the easiest to understand is that a particle runs into a fiber and sticks. Secondly, the particle gets within one diameter of a fiber of the HEPA filter and while it tries to “skid by” the fiber it is gets stuck on the fiber.  Third, as a very small, about 0.1 micron, particle moves in the gas flow it dithers about due to collisions with molecules (Brownian motion)  and again happen to slide close to a fiber and get caught.
Therefore, HEPA air purifiers stop mold spores as well as many bacteria and viruses and of course larger items such as dust. Most air purifiers claim to be 99.97% efficient at removing particles 0.3 microns from the air that passes through the HEPA filter.  The operative phrase is “pass through”!  If the airflow does not have an opportunity to pass through the HEPA filter it will not be cleaned.  Therefore the claim of 99.97% of all .3 and larger particles being removed is not accurate in poorly designed HEPA air purifiers where some of the airflow may pass around the HEPA filter and return to the room not cleaned. The IQAir HealthPro series is the only line that specifies that over 95% of the airflow that enters the air purifier goes through the HEPA filter.  As good as that sounds pure HEPA air purifiers do not remove odors, chemicals or gasses. Since these are molecular level substances the 0.3 micron holes are large compared to the gas molecules. Therefore typical HEPA air purifiers have some level of activated carbon based material to absorb odors and chemicals. The activated carbon that is included with all of these units comes in a number of varieties.  HEPA air purifiers are straight forward, a fan forces airflow through a filter.  The more times the airflow goes through the filter in an hour the cleaner the room.

Air Filter for Allergy (ies):  Allergies and asthma are a major cause of illness and disability, affecting allergic Americans from infants to seniors. Because allergies are cumulative, building in allergic symptom severity with each successive allergen exposure, minimizing exposure to all allergens is vital for all allergic individuals. Fortunately, information about allergies and allergy control products can help allergic people to live normal lives without incurring permanent damage to lungs or risking death from an asthma attack or life-threatening food allergies.  Some common allergies include:  Dust mite allergies are allergies and asthma symptoms activated by microscopic bugs that live in carpets, upholstered furniture, bed linens, mattresses and box springs, animal dander and house dust.  Pet allergies are allergies and asthma symptoms triggered by animal dander, old skin scales.  Mold allergies are allergies and asthma symptoms set off by mold, mildew and fungi, inside and out.  Allergens include substances in our environment such as pollen proteins. For an allergic individual, an allergy antibody is a fuse that ignites an allergy bomb-allergy cells that release histamine and other natural chemicals that cause allergic symptoms. Histamine can be released anywhere in the allergy-prone victim’s body. Histamine released in the nose causes sneezing and a runny nose; in the lungs causes bronchial spasms or wheezing-asthma; in the skin causes itching or hives; in the stomach causes nausea. If histamine is released through the body, a life-threatening allergic reaction – anaphylaxis – can be produced causing death without immediate treatment.  To help combat these reactions, install a Nordic Pure electrostatically charged, MERV 12 air filter in your central air conditioning and heating system to control household dust.  And replace your filters regularly.

Air Filter Comparison (s):  In an effort to aid the consumer in determining the difference between the quality of one filter compared to another, the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) developed a rating system called the MERV Rating?  MERV stands for Minimum Efficiency Reporting Value. ASHRAE assigns a MERV number intended to help people compare air filters that are for use in heating and air conditioning systems. The MERV air filter is a rating of the efficiency of the air filter, regardless of whether it is used as an air conditioner filter or furnace filter or a HVAC system that combines both heating and air conditioning into one HVAC system. The MERV rating ranks air filter efficiency by assigning a number ranging from 1 to 16, with one being the lowest air filter efficiency and 16 the highest air filter efficiency when used in an HVAC system.  Particles in the indoor air that pass through the HVAC Systems air filter are measured in microns, which is 1/1000 of a millimeter. A human hair is about 100 microns wide. Regardless of the purpose, whether it is used as air conditioning filter or furnace filter or used in a combination HVAC system, Nordic air filters capture airborne particles as small as 0.3 microns!  A MERV 12 rating represents the best balance between airborne particulate removal of dust, pollen, airborne pathogens, etc. and overall HVAC system efficiency. Air filters above MERV12 generally require larger, more expensive HVAC systems not normally intended for traditional home or smaller office heating and air conditioning systems. This is due to the “drag” imposed on the HVAC system. Top-notch HVAC professionals who buy from us daily highly endorse the MERV12 rating as providing the highest efficiency of an air filter while not overtaxing the HVAC system. MERV12 requires 80% or better air filter efficiency on 1 - 3 micron particles and a greater than 90% air filter efficiency on 3 -10 micron airborne particles when tested in accordance with ASHRAE Test Standard 52.2 used in testing air filters and air filter efficiency. Our air filters measured 97.8% air filter efficiency in removing airborne particles 3-10 microns in size, 84.1% air filter efficiency in removing airborne 1-3 microns in size and 60% air filter efficiency for smaller particles.
Our air conditioner furnace filters do not allow the growth of mold or bacteria, keeping your home healthier. No harsh chemicals are necessary to make the air conditioner furnace filter “antibacterial.” Our air conditioner furnace filters use permanently charged electrostatic material that helps dust cling to the air conditioner furnace filter. The following shows efficiency of air filters by media. As you can see from the illustration, filtration for fine fiber media such as fiberglass is greatest with larger airborne particulate and virtually non-existent with smaller airborne particulate.

NORDIC PURE FILTER EFFICIENCY

Particle Size in Microns ( 0.001 millimeters)

Air Filter Dust:  Dust is actually a combination of dirt, pollen, hair, dead skin, pet dander, dust mites, dust mite feces and a myriad of microbiological pollutants. Though there is no way to completely eliminate dust, you can control the dust with adequate filtering of the air through your HVAC filter. Choosing the right filter medium like our pleated electrostatic filter media enables maximum filtration without taxing your HVAC system. Our Merv12 air conditioner furnace filters remove up to 97.8% of pollen, pet dander, dust, mold spores, dust mites, tobacco smoke and other airborne particles, therefore helping to reduce the amount of dust while providing a more healthy indoor environment, .

Air Filter Fact (s):  Air filters come in a variety of sizes and types. The primary distinction between one filter and another is the size of the filter (length, width and thickness) and the filter material or “media” that is used in the manufacture of the filter. Nordic Pure features all of the popular sizes of air filters. Nordic can also make a filter for your system if we do not stock your size. All custom filters can be ready to ship to you within ten days to two weeks and usually costs about the same as many of our competitor’s ready-made filters.  Air in a furnace or air conditioning system first enters the home through the air return where it passes through the air filter(s) and into the air handler, over the cooling coils or heat exchanger part of the HVAC system (where the air is either cooled or heated) and out through the ductwork into the home. The circulation throughout the HVAC system is accomplished through a powerful blower system (shown above). Because the air filter is the only device in the entire HVAC system capable of removing airborne impurities, it makes sense that frequent replacement of the air filter as well as careful consideration as to the type of air filter you use will directly impact the quality of your indoor air. Conversely, ignoring the HVAC systems’ air filter means you are allowing the entry of polluted air into the entire system, driving down operating efficiency, filling up ductwork with all dust, pollen, dust mites, etc. and other airborne pollutants while exposing the building’s inhabitants to polluted air.  Though there are a wide variety of air filters, they are generally termed as disposable air filters or reusable air filters.  Reusable air filters sound good, in concept. After all, replacement costs can add up over time. The problem is that reusable air filters do not do as efficient job as desired. To begin, reusable air filters are messy when removed from the HVAC system. Then there is the problem of finding a suitable area to clean the filters. Very often, highly toxic cleaners are required for adequate cleaning of reusable air filters. Once the chemical is used on the filter, it is absorbed into the filter and therefore a certain amount of the cleaner can be released back into the circulating air posing a potential health threat. Nordic does not endorse this type of filter and does not sell reusable filters.  Make-your-own air filters are designed to enable you to construct your own filter. Buyers for these types of media filters usually do so because their HVAC system does not accommodate standard sized air filters. The most common media for filtration is fiberglass. The handling of fiberglass is difficult as fibers from fiberglass can break off in the skin causing discomfort. Further, fiberglass provides only marginal filter effectiveness. Too, the make-your-own-filters often have no frames to use in securing the media material. As a consequence, the filters can often collapse necessitating a service call by an air conditioning professional. Nordic does not endorse the use of this type of filters. Our many years of manufacturing expertise has enabled us to manufacture a custom filter at about the same price as off-the-shelf air filters from competitors. The most significant difference is that the media material is much higher in quality and has a frame around the material and the media is attached to the frame with a support material insuring there are no collapsed filters.  Disposable panel air filters are the most commonly used type of air filter in furnaces, air conditioning systems or HVAC systems. Panel air filters, being disposable, solve the problems associated with handling dirty filters while insuring ease of removal/replacement. Disposable panel air filters use a variety of media for filtration. A “panel” air filter gets its name because the air filter is actually manufactured as a self-contained, one-piece “panel” that consists of the (a.) air filter media material, (b.) any internal structure that supports the air filter media material such as metal fabric, wire or even cardboard, and (c.) the box or frame in which the air filter media material and the media support material is attached to and housed within. The box or frame of a disposable panel air filter is rigid. The frame is normally constructed of cardboard, plastic or even metal and made to withstand the insertion of the filter into the HVAC system and keep its structural integrity while the HVAC system is operating.  The frame is defined by the length, width and thickness of the box housing the filter media.  The most common type of air filters on the market is panel air filters that use fiberglass as the filter media. Fiberglass filters are very cheap and do an effective job at removing only the largest of airborne particulates. In addition to its limited ability to filter finer particulate, fiberglass is very brittle and can cause harm when handled. Further, there is a potential for the fiberglass fibers to break off and enter passing air creating a serious health problem. Nordic does not endorse the use of fiberglass filters, both because of their limited ability to filter the air, especially smaller particulate and the health implications.  Pleated air filters are much like disposable panel air filters in that the filter media is housed in a rigid panel but the difference is that the media material used to filter the air, as well as the way the material is mounted into the air filter box or frame is different. The filter media used in pleated filters most often resembles fabric and has the capability of removing significantly smaller particulate from the air. Further, when the filter media is integrated into the filter, it is pleated to provide more surface area for filtration. This pleating adds more than double the surface area of un-pleated filters. The net effect is that you end up with a filter that removes more of the particulate in the passing air AND has at least twice as much surface area. Combined, pleated air filters provide a significantly higher level of filtration.  Electrostatic pleated air filters are a more highly evolved version of the pleated air filter. In addition to a higher quality media filter material and pleats for increased surface area for filtration, electrostatic pleated air filters are also electrostatic meaning that the filter media material is electrically charged so that the media material acts much like a magnet to draw more particulate into the media filter material for more efficient filtration. Another benefit of the electrostatic material is that it does not permit the growth of bacteria, often a problem with other filters. Nordic manufactures and sells only Electrostatic Pleated Air Filters in a wide variety of lengths and widths with thickness from 1" to 5".

Air Filter (s), Free Shipping Online:  Nordic Pure offers free shipping on all orders.

Air Filter for Furnace (s):  Breathing airborne pollutants often triggers allergy, asthma, and hayfever symptoms. Pollen, molds, and dust are common in any household and can be reduced without much effort on your part. You'll breathe easier and have fewer symptoms while in your home. Having a Nordic Pure electrostatically charged MERV 12 filter installed in a well maintained central air system can result in a cleaner, healthier indoor environment.

Air Filter for Heater:  Breathing airborne pollutants often triggers allergy, asthma, and hayfever symptoms. Pollen, molds, and dust are common in any household and can be reduced without much effort on your part. You'll breathe easier and have fewer symptoms while in your home. Having a Nordic Pure electrostatically charged MERV 12 filter installed in a well maintained central air system can result in a cleaner, healthier indoor environment.

Air Filter (s) for Home:  You only want to breathe the cleanest air in your home.  Electrostatically pleated air filters are a more highly evolved version of the pleated air filter. In addition to a higher quality media filter material and pleats for increased surface area for filtration, electrostatically pleated air filters are also electrostatic meaning that the filter media material is electrically charged so that the media material acts much like a magnet to draw more particulate into the media filter material for more efficient filtration. Another benefit of the electrostatic material is that it does not permit the growth of bacteria, often a problem with other filters. Nordic manufactures and sells only electrostatic pleated air filters in a wide variety of lengths and widths with thickness from 1” to 5”.

Air Filter Installation:  Look for the arrow showing airflow direction on the old air conditioner furnace filter and remember which way that it points. Make sure that you turn off your HVAC system to stop the airflow. Remove the old air conditioner furnace filter and discard it carefully so you don’t put the dust and other airborne contaminants back in the air. Write the date you install the air conditioner furnace filters on the place indicated on the side of the air filter frame. We strongly suggest you take the time to check your air filter from time to time to make sure it is not clogged. Remember, the pollutants you see on a dirty filter could be airborne particles you breathe – Change your air filters regularly and use our FREE Better Air Reminder Service to help you! Simply go to our Better Air Reminder Service page on this site to get started or place your order and you will be automatically enrolled.  Look for the arrow showing airflow direction, and install the new pleated air filter so the air flows in the direction of the arrows. Many air conditioner furnace filters are located at air return vents, where the air flows into the wall or ceiling. Note: On some custom size air conditioner furnace filters, the arrow may not be visible. If so, the air flows from the side without the metal mesh to the side with the metal mesh.

Air Filter Manufacturers:  While there are many manufacturers of air filters, Nordic Pure is a company you can count on!  We have been in business since 1960 and our customer satisfaction speaks for itself.

Air Filter Media:  Nordic manufactures all of our air filters using a filter media that contains a permanent electrostatic charge causing dust to cling to the air conditioner furnace filter using the same principle as static electricity. As a consequence, our air filters are far more effective and efficient than traditional pleated filters. Nordic does not endorse or sell the permanent metal electrostatic filters.

Air Filter MERV Rating (s):  In an effort to aid the consumer in determining the difference between the quality of one filter compared to another, the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) developed a rating system called the MERV Rating?  MERV stands for Minimum Efficiency Reporting Value. ASHRAE assigns a MERV number intended to help people compare air filters that are for use in heating and air conditioning systems. The MERV air filter is a rating of the efficiency of the air filter, regardless of whether it is used as an air conditioner filter or furnace filter or a HVAC system that combines both heating and air conditioning into one HVAC system. The MERV rating ranks air filter efficiency by assigning a number ranging from 1 to 16, with one being the lowest air filter efficiency and 16 the highest air filter efficiency when used in an HVAC system.  Particles in the indoor air that pass through the HVAC Systems air filter are measured in microns, which is 1/1000 of a millimeter. A human hair is about 100 microns wide. Regardless of the purpose, whether it is used as air conditioning filter or furnace filter or used in a combination HVAC system, Nordic air filters capture airborne particles as small as 0.3 microns!  A MERV 12 rating represents the best balance between airborne particulate removal of dust, pollen, airborne pathogens, etc. and overall HVAC system efficiency. Air filters above MERV12 generally require larger, more expensive HVAC systems not normally intended for traditional home or smaller office heating and air conditioning systems. This is due to the “drag” imposed on the HVAC system. Top-notch HVAC professionals who buy from us daily highly endorse the MERV12 rating as providing the highest efficiency of an air filter while not overtaxing the HVAC system. MERV12 requires 80% or better air filter efficiency on 1 - 3 micron particles and a greater than 90% air filter efficiency on 3 -10 micron airborne particles when tested in accordance with ASHRAE Test Standard 52.2 used in testing air filters and air filter efficiency. Our air filters measured 97.8% air filter efficiency in removing airborne particles 3-10 microns in size, 84.1% air filter efficiency in removing airborne 1-3 microns in size and 60% air filter efficiency for smaller particles.
Our air conditioner furnace filters do not allow the growth of mold or bacteria, keeping your home healthier. No harsh chemicals are necessary to make the air conditioner furnace filter “antibacterial.” Our air conditioner furnace filters use permanently charged electrostatic material that helps dust cling to the air conditioner furnace filter. The following shows efficiency of air filters by media. As you can see from the illustration, filtration for fine fiber media such as fiberglass is greatest with larger airborne particulate and virtually non-existent with smaller airborne particulate.  Fiberglass air conditioner furnace filters are designed only to capture large particles and to protect your heating and air conditioning system; they do nothing to remove smaller particles like many allergens. These types of air conditioner furnace filters have either no MERV rating assigned to them or in some instances, have a MERV rating of from 1 to 4. Nordic Pure anti-allergenic air conditioner furnace filters not only protect your HVAC system from dust, and other airborne particles, Nordic air filters remove up to 97.8% of the pollen, pet dander, dust mites, mold spores, tobacco smoke and other airborne particles in the indoor air. Since the average person spends 2-3 times more time indoors than outdoors, it is the healthier choice.

Air Filter (s) for Mold:  Molds are forms of fungi that are found everywhere – both indoors and outdoors all year round. Outdoors, molds live in the soil, on plants and on dead or decaying matter. Another common term for mold is mildew. Mold growth is encouraged by warm and humid conditions, although it can grow during cold weather also. There are many thousands of species of mold and they can be in any color, including white, orange, green, brown, or black. Many times, mold can be detected by a musty odor. Most fungi, including molds, produce microscopic cells called “spores” that spread easily through the air. Live spores act like seeds, forming new mold growths (colonies) when they find the right conditions. All of us are exposed to fungal spores daily in the air we breathe, both outside and inside.  Most if not all of the mold found indoors comes from outdoor sources. It seems likely to grow and become a problem only where there is water damage, high humidity, or dampness. All molds need moisture to grow. Common sources of indoor moisture that can cause mold problems include flooding, roof and plumbing leaks, damp basement or crawl spaces, or anywhere moist air condenses on cold surfaces. Bathroom showers and steam from cooking may also create problems if not well ventilated.  Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture.  Controlling excess moisture is the key to preventing and stopping indoor mold growth. Keeping susceptible areas in the home clean and dry is very important. Ventilate or use exhaust fans (to the outdoors) to remove moisture where it accumulates: bathrooms; kitchens; and laundry areas. Be sure the clothes dryer vents to outside the house. Repair water leaks promptly, and either dry out and clean or replace any water-damaged materials. Materials that stay wet for longer than 48 hours are likely to produce mold growth. Lowering the humidity in the home also helps prevent condensation problems. To lower humidity during humid weather, air conditioners and dehumidifiers may be used. Proper exterior wall insulation helps prevent condensation inside the home during cold weather that could cause mold growth.  And don’t forget to use Nordic Pure electrostatic charged, MERV 12 air filters in your HVAC system.

Air Filter Performance:  There are four main types of mechanical air filter media: paper, foam, synthetics, and cotton.  Air filters are found in most all forced-air heating, ventilation, and air conditioning systems. The efficacy of the air filters in such systems significantly affects the Indoor Air Quality. Building industry recommended practices and government guidelines contain minimum recommended efficiency ratings for air filters. For example, the US Department of Energy recommends air filters with a Minimum Efficiency Reporting Value (MERV) of 13 as determined by the ASHRAE 5.2.2-1999 test protocol. And ASHRAE recommends MERV 6 or higher air filters to control the amounts of pollen, mold, and dust that reach the wet evaporator coils in air conditioning systems. Wet coils contaminated with high levels of pollen and dust can allow mold colonies to grow.  Since efficacy drops beyond a certain dirt-loading level, filters must be serviced regularly. There are a variety of different types of HVAC filters available. Many are inexpensive and not very efficient. Many in-duct filters for home forced air heating and air conditioning systems are made from loosely-spun fiberglass. These filters are inexpensive, disposable, and come in various densities and sizes. Less-dense filters allow for higher airflow, but do not remove as much dust. Higher density filters remove more particles, but are more restrictive of airflow. They also become more quickly loaded with dirt.  Polyester and/or glass fibres are commonly used to make air filters. Both materials have high temperature ratings of at least 120°C (250°F), and are widely used in commercial, industrial and residential applications. Polyester and glass fibres can be blended with cotton or other fibres to produce a wide range of performance characteristics. In some cases Polypropylene, which has a lower temperature tolerance, is used to enhance chemical resistance. Tiny synthetic fibres known as microfibres are used in many types of HEPA (High Efficiency Particulate Air) filters.

Air Filter Plus:  Nordic Pure is your complete source for air filtration products and services.

Air Filter Price (s):  Check out our anti-allergenic MERV 12 pleated air filters which significantly reduce dust in home and reduce dust mites, mold spores, pet dander, pollen, smoke particles, and other airborne particulates.  97.8% efficiency.  We’ll not only improve your indoor air quality, but you may be able to have a dust free environment and your indoor allergy may not be as bad when you are capturing the smaller particles and contaminants.  Our filter material has a permanent electrostatic charge and does not support the growth of bacteria, fungi, mildew or mold. Prices include FREE SHIPPING on any size air filters online.  We manufacture any size 1", 2" and 4" air filters and Honeywell Media Replacement filters for the Honeywell FC100A1037 filters / FC200E1037 filters (20x25x5 air filters) and for the Honeywell FC100A1029 filters / FC200E1029 filters (16x25x5).  We also make any size custom pleated air filters with fast and free shipping, so order your custom filter today and see what best air filters can do for you.  There’s no comparison for the price!

Air Filter Products:  Nordic Pure not only provides the one-stop store for your filter needs, but we now offer other products like our air freshener, Filter Breeze™.  Simply open filter unit, spray the filter, turn on air or heat and enjoy your favorite scent as it circulates throughout each room in your home. The fragrance level can be controlled by the number of sprays applied to the air filter and easily refreshed when the scent is diminished. Filter BreezeTM is great for any occasion and is available in a variety of fragrances. Try them all today!

Air Filter (s) for Purifiers:  Nordic Pure sells the BF25A HEPA/Carbon Replacement Filter for the A375UV Ultra Air Purifier. 

Air Filter Removal:  See “How to Change an Air Filter.”

Air Filter Replacement (s):  See “How to Change an Air Filter.”

Air Filter Sizes:  Nordic Pure stocks these sizes:  Pleated Filters Merv12 – 1 Inch Air Filters , 2 Inch Air filters , and 4 Inch Air Filters .  Look to us for your custom size filters, and we also carry Honeywell Merv12 - 16x25x5 FC100A1029 / FC200E1029 and 20x25x5 FC100A1037 / FC200E1037.


Air Filter Suppliers (Store) (online):  Nordic Pure is your one-stop shopping when it comes to your air filter needs.  Our customer satisfaction is guaranteed and you can find us online at www.nordicpure.com . 

Air Filtration:  The process of removing particulate material from an air stream.
Air Filtration System (s) (also Air Cleaner):  Removes airborne allergens from your home.

Airflow Air Conditioning:  Air conditioning is one of those amenities that’s easy to take for granted if you have it, and on a hot, humid summer afternoon – easy to covet if you don’t.
In fact, in relatively warm climates, central air conditioners have become more the norm than the exception. In addition to cooling, they dehumidify and filter air, making it more comfortable and cleaner.  For those who aren’t familiar with the terms, a central air conditioner works from a central location to distribute conditioned air throughout a house.
Unlike a small, window – or wall-mounted room air conditioner, designed to cool a small area, a central air conditioner borrows a central air handling unit such as a forced air furnace or heat pump and ductwork for whole-house delivery.  The related heat pump is essentially a central air conditioner that can be reversed in winter to heat a house.  Manufacturers produce air conditioners in a variety of sizes, typically measured in “tons” or “BTUs per hour.”
A BTU (British Thermal Unit) is a common unit used for measuring heat output, equal to the amount of energy required to raise one pound of water one degree Fahrenheit. One ton equals 12,000 BTUs/hour-a term derived from the amount of energy required to melt 1 ton of ice in a day.  With air conditioners, bigger is not necessarily better. For one thing, the larger the capacity, the more a unit will cost; output is directly related to cost. Also, it’s critically important to pick a size that is appropriate for the house.  An air conditioner that is too small can’t keep up with load requirements on a particularly hot day. One that is too large will cycle off and on too frequently, doing a poor job of dehumidifying the air, which degrades comfort. In fact, it’s better to slightly undersize an air conditioner than to oversize it.
Also, the air flow into and out of rooms must be carefully balanced to insure efficient operation of the system.
Airflow Alarms on Safety Cabinets:  Australian standards for safety cabinets specify that alarms be fitted that (inter alia) warn of reduction in exhaust airflow to the point where air barrier containment fails.  Cabinets that use pressure switches to operate alarms have an inherent limitation of unreliable alarm sensitivity that is exacerbated when set up with the alarm trigger point well below safe airflow.

Air Flow Direction:  Air conditioner which can adjust a direction of an air-flow being discharged into a room. The air conditioner has blades for controlling the air flow direction and a connecting bar for connecting the blades such that the blades rotate together. The blades and the connecting bar can be reassembled. The air conditioner can adjust the flow direction of the air discharged from the air conditioner, thereby uniformly conditioning the inside of a room. In addition, even if hinge bars which connect the blades and the connecting bar are damaged, the blades and the connecting bar can be reassembled.

Air Flow Filter (s):  High airflow 1" filters effectively capture larger particles from the air. These filters attract and capture household dust and are ideal for high-velocity equipment.  A filter with a micro-particle rating range of 200 - 600 is ideal for people who want to help reduce larger particles such as household dust, pollen, mold spores and pet dander from the air passing through the filter. These filters are also suitable when you have an air conditioner running.

Air Flow Furnace (s):  You likely have in your home one of two basic air delivery systems, either of which will be necessary to operate a central air conditioner: a furnace or an air handler. A furnace is comprised of a heating device (gas or electric), as well as an air circulating fan. An air handler looks very much like a furnace, but has a circulating fan without heating capability. Additionally, an air handler has an evaporator coil built-in for air conditioning (or heat pump) usage.  Your furnace or air handler will be configured one of three ways: up-flow, down-flow, or horizontal-flow. Looking at your unit will likely inform you of which one you have. If your furnace/ air handler is vertically aligned, then it is up-flow or down-flow. If it is horizontally aligned, it is horizontal-flow. 

Air Flow Resistance:  Filters of any kind present a barrier to air flowing through the ductwork in an air handling system.  This barrier creates resistance which reduces the volume of air delivered by the fan.  This phenomenon can be explained by an understanding of the pressures in an air handling system caused by the movement of air. There are three measures of pressure in an air handling system: Static Pressure is the force in all directions. (Think of it as the pressure attempting to burst the duct.) Differential Static Pressure can be positive or negative. If the Static Pressure in the duct
is higher than atmospheric pressure, it is positive. If it is lower than atmospheric pressure, it is
negative. Resistance gauges installed in an air handling system measure Static Pressure (not
Velocity Pressure).  Velocity Pressure is the pressure caused by the velocity of air moving in the direction of flow.  It is always positive.  Total Pressure is the sum of the Static Pressure and Velocity Pressure. Air handling systems are designed with a specific Total Pressure so the fan can be sized properly.  If Total Pressure equals Static Pressure plus Velocity Pressure, then as the Static Pressure
(resistance) caused by the filters increases, the velocity must decrease. Since Volume equals
Velocity times Area, any reduction in velocity reduces the volume of air moved.  Resistance is called “Pressure Drop” because the Static Pressure upstream of the filters is higher than it is downstream. Therefore, the reference to “drop.”

Air Flow Restriction:  Free airflow is essential for heating and air conditioning equipment functionality, efficiency, and durability.  Some HVAC technicians use the “plywood analogy.”  The plywood analogy simply gives us a visual representation of restricting air flow . . . if a piece of plywood was installed inside your duct work as an air cleaner you would have 100% catch efficiency on all particulate sizes, but you would also have 100% air flow restriction. Obviously, this is a ludicrous example but you should now see the balancing act between efficiency and airflow that all mechanical (media) type filters must consider. Given the two topics above, % of particulates removed:  There is a simple comparison that can be made once the two topics above are known . . . air cleaners that catch a large % of small (.01) particles while not restricting air flow are the best.

Airflow Limitation:  A prolonged forced expiratory time (longer than 4 seconds). This reflects the heterogeneity of the mechanisms involved in the physiological abnormalities of asthma.

Air Flow Sensor:  A device that measures air velocity (via differential pressure) inside a duct.

Air Flow Volume:  The amount of air that is circulated through your home or room by the air conditioner.  This is usually measured in cubic feet per minute or CFM.  This is generally referred to as air circulation.


Air Flow/Air Permeability:  Measure of the amount of air that flows through a filter – a variable of the degree of contamination, differential pressure, total porosity, and filter area.  Expressed in either cubic feet/minute/square foot or liters/minute/square centimeter at a given pressure.

Air Gap:  The space between magnetic poles or between rotating and stationary assemblies in a motor or generator.

Air Handler:  A steel cabinet containing a blower with cooling and/or heating coils connected to ducts that transport indoor air to and from the air handler.  An air moving and/or mixing unit.  Residential air handlers include a blower, a coil, an expansion device, a heater rack and filter.  Heaters for air handlers are sold as accessories.  In some models heaters are factory installed.  HVAC term for a fan-blower, heat transfer coil, and housing parts of a system.  In some systems a furnace handles this function.

Air Handler Air Filter (s):  Air handlers are a system-like device used in ventilating systems. Air handlers typically consist of a blower, heat exchange medium for heat or air conditioning, and housing. An air-conditioning system is a good example of an air handler. An air-handler unit is the main component of an air-conditioning system. An air-handler unit includes various dampers, an air filter, heating and cooling coils, and a fan. Dampers control the flow of outside air, return air, and mixed air. The air filter removes dust particles from the air, heating and cooling coils condition the air, and the fan delivers the conditioned air to various parts of the building. Air handling effectively circulates conditioned air throughout a space. When matched with a heat pump, air handling circulates both cool and hot air, depending on the season. There are several types of air handlers. Examples include an HVAC air handler, air filter handler, and hot water air handlers. HVAC stands for heating, ventilation and air conditioning. These three functions of HVAC Air Handler are closely interrelated and control the temperature and humidity of the air within a building. Air filter handlers remove dust from an air stream as the dust-laden air passes through them. Hot water air handlers consist of a hot water coil, the air handler, a condenser and/or furnace, and a water heater or boiler. Other air handlers are commonly available.  Air handlers are used in many applications. For example they can be used for providing smoke control, maintaining pressure relationships between spaces, and providing fresh air for occupants. Air handlers provide heating, cooling, ventilation, and humidity control for a building. Air handlers should adhere to American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards to provide good air filtration and to protect heating and cooling systems equipment without adding much in static pressure or pressure drop.

Air Handler/Coil Blower:  The indoor part of an air conditioner or heat pump that moves cooled or heated air throughout the ductwork of your home.  An air handler is usually a furnace or a blower coil.

Air Handling Unit (AHU):  For purposes of this document refers to equipment that includes a blower or fan, heating and/or cooling coils, and related equipment such as controls, condensate drain pans, and air filters.  Does not include ductwork, registers or grilles, or boilers and chillers.  Factory-made encased assembly consisting of a fan or fans and other equipment to circulate, clean, heat, cool, humidify, dehumidify or mix air.

Air-impermeable:  A material or assembly having an air permeance equal to or less than 0.02 l (s-m2) @ 75 Pa tested according to ASTM E 2178 or E 283.

Air Infiltration:  Air leakage into a building or interior space.  Leakage of air into rooms through cracks, windows doors and other openings.  Temperature difference, or wind.
Air Infiltration Barrier:  A woven plastic sheet that stops almost all air traveling through a building cavity, while allowing moisture to pass through the cavity.

Air Inlet:  Apertures (grilles, diffusers, or louvered openings) through which air is intentionally drawn from a conditioned space.

Air Knife:  A component on a compressed air line that provides wide area coverage with a thin sheet of air.  Also amplifies compressed air
flow, reduces noise.  Used in blowing, cooling.  Also known as air curtain.

Air Leak:  A crack or hole that accidentally admits a gas or lets it escape.  The uncontrolled flow of air for instance through a component of the building envelope, or the building envelope itself, when a pressure difference is applied across the component.  Infiltration refers to inward flowing air leakage and exfiltration refers to outward flowing air leakage.

Airline Filter:  Filter used in conjunction with other air compressor safeguards to supply cleaner air to supplied-air respirators.  Filter cartridges trap and remove oil particulates, odor and organic vapors.  Water vapor is removed by other mechanisms.
Air-line Respirator:  A respirator that is connected to a compressed breathing air source by a hose of small inside diameter.  The air is delivered continuously or intermittently in a sufficient volume to meet the wearer’s breathing requirements.

Airline Respirator:  See supplied air respirator.

Air Lock:  Device that permits passage between regions of differing air pressures, most often used for passage between atmospheric pressure and chambers in which the air is compressed.  A typical modern air lock consists of a cylinder of steel plate with airtight doors located at both ends, one opening from the outside into the lock, the other from the lock into the compressed-air chamber, together with valves to admit or to exhaust compressed air.  One of the doors must always be closed; before the other is opened, the pressure within the air lock must be equalized with that on the opposite side.  In biosafety facilities airlocks are usually two sets of doors in a corridor which when closed form a series of air locks to prevent air moving in or out of the area.  Only one door should be opened at one time.

Airlock:  Term generally applied to a rotary vane valve that keeps air from entering a dust collector, yet allows collected particulate to continuously discharge from the device.

Air Media:  Filter papers, Filter aids, Filter cloth, Filter mesh, Metal fabric media, Pressed felts, Purification, Separators, Filter media, Industrial filtering and purification, Coalescing filters, Electronic filters, Fuel filters, Gas pipeline filters, Hydraulic filters, In line filters, Light filters.

Air Monitoring:  The continuous sampling for and measuring of pollutants present in the atmosphere.

Air Motor:  A compact, low mass unit giving smooth, non-vibrating power.  Several types include vane, piston, percussion and turbine type motors.

Air Movement:  The movement of the air past a point, generally represented as the speed or velocity of the air measured with an anemometer.

Air Nozzle: A projecting aperture at the end of a tube, pipe etc. serving as an outlet for compressed air.  Reduces the demand on the compressor by generating the highest thrust and volume for the lowest possible air consumption.

Air Odor Eliminator (Removal):  Citing Robert Simmons, a microbiologist at Georgia State University, the article explained how “condensation in the (air conditioning) system makes a home for nasty spores that invade . . . and feed on insect parts trapped inside. Before long, the vents are spewing fungi and a ‘dirty sock odor’ . . . ”  What does this mean? Simmons explained, “The first thing people get are the classic allergy symptoms. Your eyes get itchy, your nose starts running and you start to sneeze.” As effective as our air filters are in controlling airborne particulates throughout the home, it is simply impossible to rid your indoor air of all the potentially harmful particulate that could be present in your indoor air. As a result, we strongly suggest the addition to various areas of your home where odors or allergens are most likely to accumulate. For example, small portable air purifiers placed in strategic areas like laundry rooms, pet rooms, bathrooms are all excellent places to locate an air purifier. Air Purifiers help neutralize odors and provide additional filtration. We are experts in air purification technology and offer only products we have tested extensively and are known for their effectiveness. For more information and to see our selection of air purifiers, go to: http://nordicpure.com/pages/store_item_list.asp?action=Level%201&cat_id=8

Air Outlet:  Apertures (grilles, diffusers, or louvered openings) through which air is intentionally delivered to a conditioned space.

Air Passages:  Openings through or within walls, through floors and ceilings, and around chimney flues and plumbing chases, that permit air to move out of the conditioned spaces of the building.

Air Permeability:  The property of a building component to let air pass when it is subjected to a differential pressure.

Air Plenum:  Any space used to convey air in a building, furnace or structure.  The space above a suspended ceiling is often used as an air plenum.

Air Pollutant:  Any substance in air that could, in high enough concentration, harm man, other animals, vegetation, or material.  Pollutants may include almost any natural or artificial composition of airborne matter capable of being airborne.  They may be in the form of solid particles, liquid droplets, gases, or in combination thereof.  Generally, they fall into two main groups:  (1.) those emitted directly from identifiable sources and (2.) those produced in the air by interaction between two or more primary pollutants, or by reaction with normal atmospheric constituents, with or without photo activation.  Exclusive of pollen, fog, and dust, which are of natural origin, about 100 contaminants have been identified.  Air pollutants are often grouped in categories for ease in classification; some of the categories are solids, sulfur compounds, volatile organic chemicals, particulate matter, nitrogen compounds, oxygen compounds, halogen compounds, radioactive compound, and odors.  Any unwanted substance in air.  Any substance that can make the air dirty or harmful.  Ozone is a pollutant because it makes the air unhealthy to breathe.  Amounts of foreign and/or natural substances occurring in the atmosphere that may result in adverse effects to humans, animals, vegetation, and/or materials.  (See also Air Pollution .)

Air Pollution:  Degradation of air quality resulting from unwanted chemicals or other materials occurring in the air.  (See also air pollutants .)  The presence in the atmosphere of gases, fumes or particulate matter alone or in combination with each other, in sufficient concentration to disturb the ecological balance; cause objectionable effects, especially sensory offenses; cause transient or chronic illnesses; or impair or destroy property.

Air Pollution and What You Can Do About It:  Http://www.arb.ca.gov/html/cando.htm     In this area, we provide some background materials concerning the problems of air pollution.  In addition, we provide access to some documents which explain ways we can help reduce air pollution in our communities. For more information, please contact Dimitri Stanich at (916) 322-2990.
50 Things You Can Do
This pamphlet shows you how to reduce air pollution.
Buyer’s Guide to Cleaner Cars
This guide can help you quickly identify the cleanest cars sold in California.
Bicycle Awareness Program
People choosing to pedal rather than drive usually replace short automobile trips that are disproportionately high in pollutant emissions.
Fact Sheets, FAQs and Videos
ARB has produced a series of general-interest easy-to-read fact sheets, “frequently asked questions,” brochures, and presentations concerning several aspects of the air quality management program.
File an Air Pollution Complaint
Help reduce air pollution by reporting smoking vehicles or idling vehicles or other general air pollution complaints.
Glossary of Air Quality Management Terms
Recognizing that our web site users might need some help in defining certain air quality management terms and acronyms, we provide here a glossary of terms to help you help us clean our air.
Indoor Air Quality Program
The goal of the Indoor Program is to identify and reduce Californians’ exposures to indoor air pollutants. Learn what you can do to lessen your exposure.
Flex Your Power
Flex Your Power’s website is your resource for energy efficiency and conservation information. Find incentives / rebates, technical assistance, product guides, and case studies. By reducing energy consumption, we all help to clean our air.
Voluntary Accelerated Vehicle Retirement
Help reduce ozone-forming emissions by accelerating normal fleet turnover so that newer, cleaner vehicles can be put into use sooner than what would occur naturally.

Air Pollution Control Device:  Mechanism or equipment that cleans emissions generated by a source (e.g. an incinerator, industrial smokestack, or an automobile exhaust system) by removing pollutants that would otherwise be released to the atmosphere.

Air Pollution Control District (APCD):  A county agency with authority to regulate stationary, indirect, and area sources of air pollution (e.g., power plants, highway construction, and housing developments) within a given county, and governed by a district air pollution control board composed of the elected county supervisors.  (See also Air Quality Management District).

Air Preheater:  Indirect heat exchanger designed to transfer heat from combustion gas to the air stream added to the combustion zone.

Air Pressure:  The pressure exerted by the air.  This may refer to static (atmospheric) pressure, or dynamic components of pressure arising from air flow, or both acting together.  The total gas pressure (static plus velocity).

Air Pressure Gradient:  Different air pressures in an animal facility’s ventilation system can be used to help create barriers to contain or exclude microorganisms.  A clean, biocontainment room or area, for example, would have a higher air pressure than the corridor, so that when the door is open, the air flows out rather than in.

Air Pump:  A pump which is used to deliver air to an aquarium.  The pump pushes air through silicon tubing and to air stones or other aquatic decor.  They are also an essential for UGFs (undergravel filters).  An air stone is placed in each clear tube.  When the air bubbles travel upward, they generate steady current which brings water from the bottom, through the tubes and to the surface.

Key Features:
• Pre-filter/Allergy-HEPA Filter/Enhanced Activated Carbon Filter all-in-one makes filter changing easy
• Effectively removes smoke, pollen, dust, animal dander, dust mites, molds, bacteria and viruses
• Enhanced activated carbon for even greater odor removal
• 2 UV lamps for bacteria removal
• 4-speed settings & 12 hour timer
• Dust sensor and Odor sensor
• Wall-mountable space saving design
• Built-in Ionizer
• Filter replacement indicator
• Digital display with simple and intuitive touch button control
• Unique safety feature has power auto-off protection when front cover removed
• Remote control
Specifications:
• Type: Allergy-HEPA air filter
• Power: 120V
• Noise: ≤65dB
• Room Size: Up to 800 square feet; 400 square feet
  for best performance
• Unit Size: 18.5" x 8.23" x 17.48"
• Unit Packaging: 21.42" x 9.92" x 20.24"
• Unit Weight: 19 lbs
FREE SHIPPING saves you $25.00!
Air Purifier Filter (s):  Alen Air replacement HEPA - Activated Carbon filter for the A375UV air purifiers.  May also be used in the A350 Alen air purifiers for improved odor removal.
Filter Quantity: 1
Filter Type: HEPA & Activated Carbon
Filter Life: 6 – 9 months
Filter Efficiency: 99.97%
Free Shipping Directly from Manufacturer!
Air Purifier Review (s):  Overview:  We tested models from 6 manufacturers at our offices with a high-tech particle counter to measure the ability to remove particles from the air which are 0.3 microns and larger.  This represents all pollen, mold spores, pet dander and most of the dust in a home.  Recommendations: We highly recommend the IQAir, Alen or BlueAir air purifiers as these units remove over 95% of all air borne particles. We do not recommend the Friedrich C-90, Ionic Breeze or Oreck XL air cleaners as they generate ozone which is harmful to the body according to laboratory research conducted by California DHS’ Indoor Air Quality Program. A detailed review of each of these units are listed below.

1. IQAir HealthPro ($699):  The IQAir model was the top performer and removed 100% of the particles when measured at the air output and removed 98% of the particles in the room after running for 20 minutes. The IQAir uses only HEPA filters and performed equally well at each fan speed.
2. Alen A350 ($399) and Alen A375UV ($499):  Both Alen air purifier units removed 98% of the particles at the unit and 97% of the particles in the room.  Both units use the same HEPA technology and the difference is the A375UV has a carbon filter plus 2 UV lamps.  These two units perform as well as the more expensive units like IQAir and BlueAir in dust and pollen removal, but cost half as much.  The other advantage to these units is the low filter replacement cost which is economical to own and operate.
3. BlueAir 601 ($599): The BlueAir 601 removed 98% of the particles measured at the unit and 96% of the particles in the room.  This model uses a combination of ionization and HEPA-like filters.  The filters are about half as dense as the IQAir filters however the ionization effect seems to compensate. The particle removal rate was lower at the higher fan speeds and this is likely due to the filters not being able to “catch” as many particles.
4. Alen T300 ($299) removed 93% of the particles at the unit. The unit comes with 2 Alen HEPA filters and a UV lamp for virus and bacteria control. The T300 was designed to offer a smaller foot print and to compete against the Sharper Image Ionic Breeze units. The primary advantage to the Sharper Image unit is the T300’s particle removal performance, sleek design and quiet operation.
5. Austin Air HealthMate ($449):   The Austin Air Healthmate removed 84% of the particles when measured at the unit and 80% of the particles in the room.  The HealthMate uses a cylinder shaped HEPA filter and also contains carbon for odor removal, although we did not test for odor removal in our study.
6. Friedrich C-90A (Discontinued):  The Friedrich C-90A removed 68% of the particles when measured at the unit and 90% in the room.  The C-90A uses electrostatic plates to charge and catch the particles as they pass through.  At the higher fan speeds the performance was worse and we attribute this to the air moving too quickly for the particles to attach to the plates.
7. Hunter 30756 Permalife ($249):
8. Oreck Air Purifier ($349):  The Oreck air purifier was one of the worst performing unit of those that we tested, in that it removed 33% of the particles at the unit and 45% in the room.  This is similar to the Friedrich C-90A in technology, only smaller and more attractive.  It had the same issue as the C-90A on the higher speeds in that fewer particles were being trapped in the unit.  Also, it appears to emit a small amount of ozone and one of our employees complained about an odor and had a headache when the unit was run.
9. Sharper Image Quadra Ionic Breeze Air Purifier ($350):  The Sharper Image air purifier was the worst performing unit we tested, in that it only removed 30% of the particles at the unit and 5% in the room – we were generous with the 5%.  We even tested this unit beyond our standard 20 minute duration and extended it for an entire day.  This unit still didn’t remove any significant particles from the room.  We did not see a layer of dust on the electrostatic plates during our test.

Air-purifying Respirator:  A respirator that uses chemicals to remove specific gases and vapors form the air or that uses a mechanical filter to remove particulate matter.  An air- purifying respirator must only be used when there is sufficient oxygen to sustain life and the air contaminant level is below the concentration limits of the device.

Air Quality Index (AQI):  A numerical index used for reporting severity of air pollution levels to the public.  It replaces the formerly used Pollutant Standards Index (PSI).  Like the PSI, the AQI incorporates five criteria pollutants – ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide – into a single index.  The new index also incorporates the 8-hour ozone standard and the 24-hour PM2.5 standard into the index calculation.  AQI levels range from 0 (Good air quality) to 500 (Hazardous air quality).  The higher the index, the higher the level of pollutants and the greater the likelihood of health effects.  The AQI incorporates an additional index category – unhealthy for sensitive groups – that ranges from 101 to 150.  In addition, the AQI comes with more detailed cautions.

Air Quality Management District (AQMD):  A group of counties or portions of counties, or an individual county specified in law with authority to regulate stationary, indirect, and area sources of air pollution within the region and governed by a regional air pollution control board comprised mostly of elected officials from within the region.  (See also air pollution control district).

Air Quality Management Plan (AQMP):  A plan prepared by an APCD / AQMD, for a county or region designated as a nonattainment area, for the purpose of bringing the area into compliance with the requirements of the national and/or California ambient air quality standards.  AQMPs are incorporated into the State Implementation Plan (SIP).

Air Quality Manager:  An individual employed by the local, state, or federal government to manage air quality.

Air Quality Simulation Model:  A mathematical relationship between emissions and air quality which simulates on a computer the transport, dispersion, and transformation of compounds emitted into the air.

Air Quality Standard (AQS):  The prescribed level of a pollutant in the outside air that should not be exceeded during a specific time period to protect public health.  Established by both federal and state governments.  (See also Ambient Air Quality Standards).

Air Quality Working Groups (AQWG):  Advisory groups that provide forums for communication, cooperation, and coordination in the development and implementation of air quality control measures.  They may be comprised of representatives from the ARB, citizen groups, environmental groups, industry, local air districts, and the U.S. EPA.

Air Receiver:  A receptacle which serves to store compressed air for heavy demands in excess of compressor capacity.

Air Resources Board: (See California Air Resources Board.)

Air Retarder/Barrier:  A material or structural element that inhibits air flow into and out of a building’s envelope or shell.  This is a continuous sheet composed of polyethylene, polypropylene, or extruded polystyrene.  The sheet is wrapped around the outside of a house during construction to reduce air in-and exfiltration, yet allow water to easily diffuse through it.

Air Sampling:  Test of the amount of dust in the air workers breathe.  Lightweight, portable equipment is used.  Air sampling should be done by a trained professional.

Air Sealing:  The practice of sealing unintentional gaps in the building envelope (from the interior) in order to reduce uncontrolled air leakage.  Also known as “house doctoring.”  Air sealing is a systematic approach to “tightening” a dwelling unit’s heated envelope (building shell) to reduce uncontrolled heat loss through air leakage points present in the shell.  The prevalent technique is to perform this tightening from the interior of the home.  Trained workers seal the air leakage points using a variety of materials, such as insulation, caulk, foam, vapor barriers, and weather-strip.  Air leakage identification is usually aided by using diagnostic equipment like blower doors and infrared scanners, since many leakage point are not obvious to the naked eye.  Part of the air sealing protocol includes testing to ensure that the building envelope is not sealed too tightly.  Over-tightening can result in health and safety problems for the occupants, including back drafting of combustion equipment (furnaces, hot water heaters) and moisture condensation causing mold and mildew on surfaces.

Air Sensor:  A device that registers changes in air conditions such as pressure, velocity, temperature, or moisture content.

Airshed:  A subset of air basin, the term denotes a geographical area that shares the same air because of topography, meteorology, and climate.

Air Shower:  An air shower is a hallway or room leading to the entrance of a cleanroom.  In an air shower, high velocity air blows off particles that could contaminate a cleanroom.  Sometimes, air showers are combined with static removal equipment or HEPA filters to make them more effective at removing hair and other contaminants.

Air Source Equipment:  Heat pumps or air conditioners that use the outdoor air to transfer heat to and from the refrigerant in the unit.

Air Space:  The area between insulation facing and interior of exterior wall coverings. Normally a 1" air gap.

Air Standard:  Dry air at 70 degrees F and 29.92" mercury pressure.  Air having a temperature of 68oF (20oC), a relative humidity of 36% at 14.7 psia.

Air Stream:  A current of air; airflow.

Air Supply Volume:  The volume of supply air flowing through a cross-sectional plane of a duct per unit time, found by multiplying air velocity by the cross-sectional area of the duct.

Air Terminal Device:  A device located in an opening provided at the boundaries of the treated space to ensure a predetermined motion of air in this space.

Air Tightness:  The degree to which unintentional openings have been avoided in a building’s structure.

Air to Air:  Both the condensing and evaporating mediums are air.

Air-to-Cloth (A/C) Ratio:  The ratio of gas volume (acfm) to effective cloth area (sq. ft.). In SI units A/C = m3/m2.

Air-to-Media Ratio:  The ratio of air volume (ACFM) to square feet of effective filter media area.  Also referred to as the apparent or face velocity through the media (FPM).  Typically 3 to 20 fpm for bag medias and 0.5 to 6 fpm for pleated-type media.

Air Toxics:  A generic term referring to a harmful chemical or group of chemicals in the air.  Substances that are especially harmful to health, such as those considered under U.S. EPA’s hazardous air pollutant program or California’s AB 1807 and/or AB 2588 air toxics programs, are considered to be air toxics.  Technically, any compound that is in the air and has the potential to produce adverse health effects is an air toxic.  Also known as toxic air pollutants or hazardous air pollutants are those pollutants known to or suspected of causing cancer or other serious health problems.  Health concerns may be associated with both short and long term exposures to these pollutants.  Many are known to have respiratory, neurological, immune or reproductive effects, particularly for more susceptible sensitive populations such as children.  Any air pollutant for which a national ambient air quality standard (NAAQS) does not exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur dioxide, nitrogen oxide) that may reasonably be anticipated to cause cancer; respiratory, cardiovascular, or developmental effects; reproductive dysfunctions, neurological disorders, heritable gene mutations, or other serious or irreversible chronic or acute health effects in humans.

Air Velocity:  Rate of speed of an airstream, expressed in fpm.

Air Vent (s):  A fitting used to vent air manually or automatically from a system.  HVAC term for a valve, either manual or automatic, that is used to remove unwanted air from the highest point of a piping system.

Air Vent Filter (s):  Has a permanent electrostatic charge to help trap dirt, dust, smoke and pollen sized particles through furnace/AC registers.  Keeps dirt & objects from falling into ducts. This is not a pleated filter, it is only 1/8" thick and can be trimmed to fit standard size vents – 4" X 12" and under.  Why use AIR Vent Filters? 

• Air Register Vent Filters are made of a self-charging electrostatic material that acts as a dust magnet for your vent register system. 
• Use in bathrooms, bedrooms, kitchen, family room and RV/Motor Homes. 
• When air flows through the filter, dirt, dust, smoke, and pollen sized particles are trapped. Filtered air then passes back into your house. 
• Keeps dirt and objects from falling into ducts. 
• Air Vent Filters are designed to provide filtered air in your home.

Air Ventilation:  Ventilating is the process of “changing” or replacing of air in any space to remove moisture, odors, smoke, heat, dust and airborne bacteria. Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.   Ventilation is used to remove unpleasant smells and excessive moisture, introduce outside air, and to keep interior building air circulating, to prevent stagnation of the interior air.

Airway:  A space between roof insulation and roof boards provided for movement of air.

Airways:  Hollow tubes to and within the lungs through which air passes during breathing. These include the trachea, bronchi, and bronchioles.

Akylation:  Input definition.

Alameda County Flood Control and Water Conservation District Zone 7:  Also known as the Zone 7, the water agency for the Livermore-Amador Valley with responsibility for regional flood control and drinking water supply.

ALARA:  As Low As Reasonably Achievable.  The design philosophy used to determine the need for, or extent of, air cleaning and off-gas facilities, based on their cost effectiveness in reducing adverse impact with respect to offsite and onsite dose criteria.  Formerly known as ALAP.

Alarm System:  Warning devices, installed or free-standing, including but not limited to: carbon monoxide detectors, flue gas and other spillage detectors, security equipment, ejector pumps and smoke alarms.

Albedo:  The proportion of the global solar radiation that is reflected by the surface of the Earth.  Will clearly vary with materials and topography.

Albumin:  Albumin is one of the major plasma proteins. It has many functions in the blood plasma including carrying molecules (and some drugs) throughout the body.

Alcohol Brine:  Water and alcohol solution witch remains a liquid below 32oF.

Key Features:

• Pre-filter/HEPA Filter
• Enhanced activated carbon filter for even greater odor removal
• Effective removal of smoke, pollen, dust, animal dander, dust mites, molds, bacteria and viruses
• UV lamp for bacteria removal
• 4 fan speed settings
• 12-hour timer

• Built-in ionizer that minimizes pollutants and produces no ozone

• Filter replacement indicator
• Digital display with simple, intuitive touch-button controls
• Unique safety feature with power auto-off protection when cover removed

Specifications:

• HEPA Filter Efficiency: ≥99.97%
• Energy Consumption:  65W
• Room Size: Up to 300 square feet; 225 square feet for optimal performance
• Unit Size: 11" x 9" x  28"
• Unit Weight:  12 lbs.

The Alen T100 Desktop Tower air purifier delivers style and performance with a compact design. Ideal for use in smaller environments such as an office cubicle or small room, the T100 offers Allergy-HEPA filtration with activated carbon filters for enhanced odor removal.
The T100 has affordable replacement filters that are easy to change, eliminating the need to come in contact with the very particles you want to avoid. With ionic-type tower units, you come in contact with those particles with each cleaning.
The T100 is a great choice for those who want a sleek, compact design without having to sacrifice performance.
Key Features:

• Pre-filter/Allergy-HEPA Filters
• Enhanced activated carbon filter for even greater odor removal
• Effectively removes smoke, pollen, dust, animal dander, dust mites, molds, bacteria and viruses
• 3 fan speed settings
• Built-in ionizer minimizes pollutants and produces no ozone
• Digital display with simple and intuitive touch button control
• Unique safety feature has power auto-off protection when cover removed

Specifications:

• Filter type: Allergy-HEPA
• Energy Consumption: 45W
• Room Size: Up to 125 square feet
• Unit Size: 6" x 10" x 15"
• Unit Weight: 8 lbs

Lightning Air is the Solution.  Modern buildings are constructed so tightly that odors and pollutants are trapped inside.  Nature’s own cleansing process, which uses both activated oxygen and negative ions are left outside.  Dust, pollen, molds, mildew, bacteria and viruses can fill the air in our living spaces.  These can cause odors, irritation and allergic response.  Fumes from paints, cleansers, carpets, pressed board, fabrics and other chemicals are also breathed in daily by you and your family.  According to the EPA, many pollutants in the typical home or office are at least 10 times higher than in outdoor air.  The average American spends 90% of their time indoors.
Item Number:  LA-2spx
Name:  Lightning Air Plus Air Purifier w/ Optional HEPA Filter
Description:  Covers up to 3500 sq ft. Totally portable, just plug in and start to enjoy clean, mountain-fresh air. No filters to replace, low energy consumption, simple plate removal for cleaning. This unit now includes a HEPA Filter that can be attached to the back side.  Price includes Free Delivery! No mechanical differences from LA-2 and LA-2sp series. Just some cosmetic changes and a NEW Limited Lifetime Warranty.
Specifications:                                                     Dimensions:
120 volt, 60hz, input                                           Height: 12.5 in
40 watts power consumption                               Width: 8.25 in
12-15 kv ion generator power supply                   Depth: 9.1 in
120 cfm, 12 volt DC variable speed fan                Weight: 16lbs
Ozone Generation:  Double Cold Plasma Dialectic Plate generation. Ozone output varies with level of humidity, temperature, and other environmental factors.
Coverage:  Purifies a range of 200-3500 square feet depending on variables such as humidity, placement, amount of pollution and temperature.  NEW: Lifetime Limited Warranty.  For the lifetime of the original purchase. LightningAir will replace any defective part due to manufacturing defect at no charge. The customer is responsible for labor charges and for safely shipping the unit to the Service Center. LightningAir will return the unit via UPS ground.  LightningAir purifiers are serviced and warranted by the LightningAir Service Center at 2940 Kerry Forest Parkway, Tallahassee, Fla. 32309. For up to 90 days from original date of purchase, LightningAir will replace or repair the product without charge to the customer should the unit prove to have a manufacturing defect.  Simply call LightningAir for authorization and for UPS pickup at no charge to the customer.

Algae:  Microorganisms that may grow to colonies in damp environments, including certain rooftops.  They can discolor shingles.  Often described as “fungus.”  Microscopic plants which contain chlorophyll and live floating or suspended in water.  They also may be attached to structures, rocks or other submerged surfaces.  They are food for fish and small aquatic animals.  Excess algal growths can impart tastes and odors to potable water.  Algae produce oxygen during sunlight hours and use oxygen during the night hours.  Their biological activities appreciably affect the pH and dissolved oxygen of the water.  Simple rootless plants that grow in sunlit waters in proportion to how many nutrients are available.  Unicellular to multicellular plants that occur in fresh water, marine water, and damp terrestrial environments.  All algae possess chlorophyll, the pigment (e.g. green, brown, and/or red) essential for photosynthesis.

Algal bloom:  Sudden, massive growths of microscopic and macroscopic plant life, algae, and cyanobacteria, which develop in lakes, reservoirs, and marine waters.

Algicide:  Any substance or chemical specifically formulated to kill or control algae.
Alkali:  Any chemical with a high pH that in water solution is irritating or caustic to the skin.  Strong alkalis in solution are corrosive to the skin and mucous membranes.  Example: sodium hydroxide, referred to as caustic soda or lye.  Alkalis turn litmus paper blue and have pH values from 8 to 14.  Another term for alkali is base.

Alkaline:  A chemical term for solutions that neutralize acids, and have a pH greater than 7.

Alkaline Gases:  Gases which are alkalis or produce alkalis in reaction with moisture; for example, ammonia, phosphine.

Alkalinity:  The capacity of water to neutralize acids, a property imparted by the water’s content of carbonates, bicarbonates, hydroxides and occasionally borates, silicates and phosphates.  It is expressed in milligrams per liter of equivalent calcium carbonate.

Allen Air Purifier (s):  See Alen air purifiers.

Allergen:  When an antigen induces an allergic reaction, it’s called an allergen.  The threshold at which an allergic reaction occurs is different for every person.  An allergen is a substance found in the indoor or outdoor environment that is normally harmless to most people.  However, people that have a genetic or developed sensitivity to specific allergens will react to these normally innocuous substances as if they were harmful to their health, triggering a release of chemicals typically referred to as an allergic reaction.  An allergen is a normal substance that causes an acute defensive reaction in a person’s immune system.  Common allergens are pet dander, smoke, and pollen, although the list of possible allergens is long and varied.  When a person has a reaction to an allergen that person is said to be allergic to it.

Allergen/Allergy:  All of us are exposed to different potential allergens at different times of the day.  For example, if you go out to work and are affected during the working day then something in your work environment may be the trigger.  If your symptoms are worse at bedtime, then it could be house dust mites in and around your bedding that are the trigger.  Where you are when a bout of sneezing starts, as well as the time of day, can provide clues to identify your allergy triggers.  For example, if you suffer from airborne allergy symptoms when you are out in countryside then, for you, pollen is most likely a trigger.  If this affects you for quite a large part of the spring and summer, then you may be allergic to more than one sort of pollen.  There are several triggers that can affect you in the garden.  Mowing the lawn throws grass pollen into the air, digging or potting out plants can release mould spores from the soil.

Allergen Immunotherapy:  A process of administering allergenic extracts to patients who suffer from allergic rhinoconjunctivitis and allergic asthma to decrease the degree of hypersensitivity and symptoms by reducing immunologic responses to environmental allergens like pollen, dust, animal dander, and molds; also highly effective for preventing anaphylaxis in patinets allergic to bee venom.  Syn: allergy vaccine therapy.

Allergic Diseases:  Diseases characterized by allergic responses to pollutants.  The hypersensitivity diseases most clearly associated with indoor air quality are asthma, rhinitis, and hypersensitivity pneumonitis.  Hypersensitivity pneumonitis is a rare but serious disease that involves progressive lung damage as long as there is exposure to the causative agent.

Allergic Respiratory Disease: Allergy resulting from inhaled substances affecting the respiratory system.

Allergic Rhinitis:  Rhinitis associated with hay fever; allergic rhinitis is manifest by sneezing, rhinorrhea, nasal congestion, pruritus of the nose, ears, palate; may also occur concurrently with allergic conjunctivitis.  Inflammation of the mucous membranes in the nose that is caused by an allergic reaction.

Allergy:  Hypersensitivity caused by exposure to a particular antigen (allergen) resulting in a marked increase in reactivity to that antigen on subsequent exposure, sometimes resulting in harmful immunologic consequences.  See also: allergic reaction, anaphylaxis, immune.  Syn:  acquired sensitivity, induced sensitivity.  (1.) That branch of medicine concerned with the study, diagnosis, and treatment of allergic manifestations.  (2.) An acquired hypersensitivity to certain drugs and biologic materials.  A state of abnormal and individual hypersensitivity acquired through exposure to a particular substance called an allergen.  A state of immunologically mediated hypersensitivity to a foreign material that is inhaled, ingested, or touched.  Abnormal reaction to a stimulus called an allergen.  Allergy refers to the abnormal response of the airways to inhaled stimuli, such as pollen, or to consumed items, such as foods, that may cause unusual airway reactions and lead to bronchospasm.  Allergy is a broad term applied to disease symptoms following exposure to a previously encountered substance (allergen), often one which would otherwise be classified as harmless; essentially a malfunction of the immune system.  In most cases, allergy involves an abnormally high, acquired sensitivity to certain substances, such as drugs, pollens or microorganisms, which may include such symptoms as sneezing, itching and skin rashes.  Allergic manifestations of major importance occur in about 10 percent of the population.

Allergy Relief Information and Services:  Air Purifiers – Find high-quality name-brand air purifiers for discounted prices at www.airpurifier-s.com.  Allergy Relief – If you need Allergy Relief find great medical info here at www.Relief-allergy.info.  Find Allergy Information and Natural Treatments to relieve allergies at www.allergies.health.mysearchisover.com/allergies.

Alligatoring:  A condition of paint or aged asphalt brought about by the loss of volatile oils and the oxidation caused by solar radiation.  Causes a coarse checking pattern characterized by a slipping of the new paint coating over the old coating to the extent that the old coating can be seen through the fissures.  “Alligatoring” produces a pattern of cracks resembling an alligator hide and is ultimately the result of the limited tolerance of paint or asphalt to thermal expansion or contraction.

Allowable Span:  The distance between two supporting points for load bearing lumber such as joists, rafters or a girder.

Allowance(s):  A sum of money set aside in the construction contract for items which have not been selected and specified in the construction contract.  Best kept to a minimum number and used for items whose choice will not impact earlier stages of the construction.  For example, selection of tile because flooring may require an alternative framing or underlayment material.  (Also, money that your parents give you as a child.)

Alluvium:  Sediment deposited by flowing water.  A general term for detrital deposits made by streams or river beds, flood plains, and alluvial fans.  The term applies to stream deposits of recent time.  It does not include sub-aqueous sediments of seas and lakes.  

Alpha Particle:  Positively charged particle emitted from the nucleus of an atom, having mass and charge equal to those of a helium nucleus (two protons and two neutrons).  Alpha particles are one of the primary types of radiation associated with radioactivity and exist as energetic nuclei of helium atoms, consisting of two protons and two neutrons. Alpha rays are heavy, slow moving charged particles that travel only one or two inches in air, and can be stopped by a piece of paper or the outer dead layer of human skin.

Alpha1-Antitrypsin (AAT):  (Also called alpha antiproteinase or AAP).  A protective material produced in the liver and transported to the lungs to help combat inflammation.  Deficiency states occur as the result of hereditary defects.

Alpha2 Adrenergic Receptor Agonists:  This is a group of pain relieving drugs that includes xylazine and medetomidine.

ALT:  ACRONYM – Altitude.

Alternating Current (AC):  An electrical current that periodically reverses its direction.  Standard in US and Canada is 60 cycles per second.  Europe and other countries is 50 cycles per second.

Alternative Energy:  Energy from a source other than the conventional fossil-fuel sources of oil, natural gas and coal (i.e., wind, running water, the sun).  Also referred to as “alternative fuel.”

Alternative Energy Sources:  Energy sources, which can be substituted for fossil fuels, nuclear power, and large-scale hydroelectric power; e.g., solar, wind, geothermal, biomass.

Alternative Fuels:  An alternative fuel is any fuel other than gasoline and diesel fuels, such as methanol, ethanol, compressed natural gas, liquefied petroleum gas (LPG) and other gaseous fuels, and electricity.  Alternative fuels may have particularly desirable energy efficiency and pollution reduction features.  The 1990 Clean Air Act encourages development and sale of alternative fuels.  Alternative fuels may have particularly desirable energy efficiency and pollution reduction features.

Altitude:  The height above sea level of a given location.  Density corrections for altitude are made using the following formula, where Z is the feet above sea level.  Density (Alt) = Density (Std) x [1 – (6.73 x 10-6) Z]5.258.

Altitude Angle:  The angular height of above the horizon, i.e. the solar altitude is the angle between the centre of the sun and the horizon.

Aluminum Separator:  Corrugated aluminum used to separate the folds of a pleated filter medium and provide air channels between them.

Aluminum Wire:  A conductor made of aluminum for carrying electricity.  Aluminum is generally limited to the larger wire sizes.  Due to its lower conductivity, aluminum wire smaller than No. 12 is not made.  Aluminum is lighter and less expensive than copper, but does not conduct as well.  It also breaks easily.

Alveoli:  Part of the respiratory system; the millions of tiny compartments within the lungs at the ends of the airways (Picture bunches of hollow grapes at the ends of hollow stems).  Alveoli are also called “air sacs.”  They are where gas exchange takes place; where the blood picks up oxygen (from air a person has breathed in) and releases carbon dioxide (to be breathed out).  Singular: Aveolus.

Amagat’s Law:  States that the volume of a mixture of gases is equal to the sum of the partial volumes which the constituent gases would occupy if each existed alone at the total pressure of the mixture.

Amana Furnace Filter (s):  Amana furnace filters come in the following sizes – BBA36 14.62" x 19.75", and BBA60 19.75" x 22.75".

Ambient:  Refers to “common” environmental conditions in which experiment is conducted.  For example:  14.7 psia and 20º to 25ºC (room temperature).  Environmental or surrounding conditions.  In this assessment, ambient air refers to the air surrounding a person through which pollutants can be carried.

Ambient Air:  Any unconfined portion of the atmosphere open air, surrounding air.  Generally, the air surrounding an object or building.  Surrounding atmosphere, usually the outside air, as it exists around people, plants, and structures; not considered in monitoring purposes when immediately adjacent to emission sources.  Often used interchangeably with “outdoor air.”

Ambient Air Blower:  See ambient air system.

Ambient Air Compressor:  See ambient air system.

Ambient Air Pump:  See ambient air system.

Ambient Air Quality Standards (AAQS): Health- and welfare-based standards for outdoor air which identify the maximum acceptable average concentrations of air pollutants during a specified period of time. (See also CAAQS and NAAQS and Criteria Air Pollutant.)

Ambient Air System:  A low pressure ambient air moving device used to deliver air directly to a supplied air respirator; this includes ambient air blowers and ambient air pumps, which typically operate at pressures below 103.4 kPa (15psig); refer to CSA Z180 for the definition.
Ambient Lighting:  Lighting spread throughout the lighted space for safety, security, and aesthetics.

Ambient Pressure:  The air pressure caused by the weight of the surrounding atmosphere.

Ambient Temperature:  The temperature surrounding an object.

AMC:  Airborne Molecular Contamination.

AMCA:  Air Movement and Control Association.

American Air Filter (s):  HEPA filters can remove at least 99.97% of airborne particles 0.3 micrometers (µm) in diameter. Particles of this size are the most difficult to filter and are thus considered the most penetrating particle size (MPPS). Particles that are larger or smaller are filtered with even higher efficiency.  HEPA filters are composed of a mat of randomly arranged fibres. Key metrics affecting function are fibre density and diameter, and filter thickness. The air space between HEPA filter fibres is much greater than 0.3 μm. The common assumption that a HEPA filter acts like a sieve where particles smaller than the largest opening can pass through is incorrect. Just as for membrane filters, particles so large that they are as wide as the largest opening or distance between fibres can not pass in between them at all. But HEPA filters are designed to target much smaller pollutants and particles are mainly trapped (they stick to a fibre) by one of the following three mechanisms:

1. Interception, where particles following a line of flow in the airstream come within one radius of a fibre and adhere to it.
2. Impaction, where larger particles are unable to avoid fibres by following the curving contours of the airstream and are forced to embed in one of them directly; this increases with diminishing fibre separation and higher air flow velocity.
3. Diffusion, an enhancing mechanism is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 µm in diameter, which are thereby impeded and delayed in their path through the filter; this behaviour is similar to Brownian motion and raises the probability that a particle will be stopped by either of the two mechanisms above; it becomes dominant at lower air flow velocities.

Diffusion predominates below the 0.1 μm diameter particle size. Impaction and interception predominate above 0.4 μm. In between, near the 0.3 μm MPPS, diffusion and interception predominate.  The initial filter air flow resistance and final filter air flow resistance are typically measured as pressure drop across the filters.  The original HEPA filter was designed in the 1940s and was used in the Manhattan Project to prevent the spread of airborne radioactive contaminants. It was commercialised in the 1950s, and the original term became a registered trademark and a generic term for highly efficient filters. Over the decades filters have evolved to satisfy the higher and higher demands for air quality in various high technology industries, such as aerospace, pharmaceutical processing, hospitals, healthcare, nuclear fuels, nuclear power, and electronic microcircuitry (computer chips).  Today, a HEPA filter rating is applicable to any highly efficient air filter that can attain the same filter efficiency performance standards as a minimum and is equivalent to the more recent NIOSH N100 rating for respirator filters. The United States Department of Energy (DOE) has specific requirements for HEPA filters in DOE regulated applications. Products that claim to be “HEPA-type,” “HEPA-like,” or “99% HEPA” do not satisfy these requirements and may not be tested in independent laboratories.

American National Standards Institute:  See “ANSI.”

American Society for Testing and Materials (ASTM): A nonprofit organization that provides a forum for producers, consumers, and representatives of government and industry, to write laboratory test standards for materials, products, systems, and services. ASTM publishes standard test methods, specifications, practices, guides, classifications, and terminology.

American Standard Air/Furnace Filter (s):  A furnace is not a household appliance. It is complex and requires professional maintenance and repair.  However, there are a few simple things you need to do on a regular basis to keep your air/furnace unit in good repair.  If you find that your home has insufficient heating or that the blower operates continuously, your unit may have dirty air filters or a blocked supply or return registers.  Clean or replace the filters and make sure the registers are open and no obstacles are blocking off the air.

Ammeter:  An instrument for measuring the current in amps, milliamps or micro amps.

Ammonia (NH3):  A naturally occurring, gaseous compound of nitrogen.  Sometimes referred to as unionized ammonia.  A pungent colorless gaseous compound of nitrogen and hydrogen that is very soluble in water and can easily be condensed into a liquid by cold and pressure.  Ammonia reacts with NOx to form ammonium nitrate – a major PM2.5 component in the Western United States.

Ammonium (NH4):  Ionized ammonia referred to as the ammonium-ion or dissociated ammonia.

Amonton’s Law:  States that the pressure of a gas, at constant volume, varies directly with the absolute temperature.

Amortization:  A payment plan by which a loan is reduced through monthly payments of principal and interest.

AMP:  ACRONYM – A unit of electrical current or rate of flow of electrons through a conductor.  One volt across one ohm of resistance causes a current flow of one ampere.  One ampere is equal to 6.25 x 1018 electrons per second passing a set point in a circuit.  Ampere.

Ampacity:  Refers to the how much current a wire can safely carry.  For example, a 12 gauge electrical copper wire can safely carry up to 20 amps.

Amperage:  The rate of flow of electricity through wire – measured in terms of amperes. For vacuum cleaners, the term “amps” indicates the amount of electrical current that a vacuum motor uses while operating.  Theoretically, the more amps a motor draws, the more powerful it is.  However, amp ratings alone do not take into account the resistance of the filter system and a number of other factors.  The all-important measurement is airflow, which is a result of the design of the entire vacuum cleaner system and not just the electricity consumption of the motor.  (See “Airflow”).

Ampere (AMP):  A unit of electrical current or rate of flow of electrons through a conductor.  One volt across one ohm of resistance causes a current flow of one ampere.  One ampere is equal to 6.25 x 1018 electrons per second passing a set point in a circuit.

Amplification (amplification source):  The process of indoor growth leading to an increased indoor microbial concentration compared to the immediate outdoor environment.

Amplitude:  The highest value reaches by voltage, current or power during a complete cycle.

Amps (AMPERES):  The rate at which electricity flows through a conductor.

Anaemic Hypoxia:  Hypoxia caused by a reduction in the oxygen-carrying capacity of the blood; for example, carbon monoxide poisoning.

Anaerobic:  In the absence of oxygen.  Organism capable of growing without the presence of oxygen.

Anaerobic Decomposition:  Decomposition of cellulose and proteins occurring in the absence of oxygen, such as in landfill waste, producing methane and carbon dioxide. Anaerobic bioreactors increase the rate of methane generation, which can then be collected and used for energy recovery.

Analogue:  A system in which data is represented as a continuously varying voltage.

Analysis of Variance:  T-test of whether two or more sample means are statistically different.

Analyte:  Specific component measured in a chemical analysis.

Anaphylactic Shock:  Anaphylactic Shock is a unique form of allergic reaction. It’s characterized by a swelling of body tissues including the throat, difficulty in breathing and a sudden fall in blood pressure.  This type of allergic reaction is extremely dangerous and can be life threatening.  If you experience this type of reaction, go immediately to your nearest hospital.  If you have had this type of reaction previously, in a mild form, you should consider carrying an Epipen with you in order to be able to deliver a potentially life-saving dose of adrenaline to counteract the reaction, until you can get to a hospital.

Anaphylaxis:  Pronunciation (an′ă-fi-lak′sis).  A generalized allergic reaction (also called anaphylactic shock) in sensitized individuals that results in life-threatening symptoms which may include vascular collapse, shock and respiratory distress.  An induced systemic or generalized sensitivity; at times the term anaphylaxis is used for anaphylactic shock.  The term is commonly used to denote the clinical reaction seen with system IgE-mediated hypersensitivity reaction.  Multivalent antigen crosslinks IgE on the surface of tissues mast cells, causing degranulation with release of preformed mediators (e.g., histamine).  Generation of newly synthesized mediators occurs rapidly.  The physiologic manifestations reflect the biologic effects of these mediators.  Cutaneous symptoms include pruritus, erythema, urticaria, and angioedema.  Respiratory compromise can come from laryngeal obstruction or bronchospasm.  Cardiac effects include arrhythmia, hypotension, and shock.  The reaction may be fatal if asphyxiation or cardiovascular collapse occurs.  Syn: anaphylactic reaction.

Anchor Bolts:  In residential construction, bolts used to secure a wooden sill plate to a concrete or masonry floor or wall.  In commercial construction, bolts which fasten columns, girders or other members to concrete or masonry such as bolts used to anchor sills to masonry foundation.

Ancillary Equipment:  Components subordinate to the compressor.

Anderson Sampler:  A sieve-type air sampling device that uses a vacuum pump to draw air through a radial pattern of 300 small holes, impacting particles in each of the small streams of air onto the surface of microbial growth medium.

Anemometer:  An instrument for measuring the force or speed of air.  A device that reads air velocity such as a wind vane.  In fan applications, it is usually a spinning-vane-type instrument used to read low velocities at registers and grills.  Common electrical types are hot wire or and the hot-body anemometers.  The principle used is to apply a fixed electrical current to a wire and the voltage over the wire is measured.  The current heats the wire.  Moving air cools the wire, decreasing the electrical resistance.  This change is measured through the voltage across the wire.

Angioedema:  Pronunciation (an′jē-ō-ĕ-dē′mă).  Recurrent large circumscribed areas of subcutaneous or mucosal edema of sudden onset, usually disappearing within 24 hours; frequently, an allergic reaction to foods or drugs.  Syn: angioneurotic edema, giant hives, giant urticaria, periodic edema.

ANLG:  ACRONYM – Analog.

Angle Iron:  A piece of iron that forms a right angle and is used to span openings and support masonry at the openings.  In brick veneer, they are used to secure the veneer to the foundation.  Also known as shelf angle.

Angle Stop:  A shutoff valve in which the inlet connects to the water supply pipe in the wall and the outlet angles 90 degrees upward toward the faucet or toilet.

Angstrom:  A unit of length 10-10 meter used to express wave lengths.  Used in measurements of RO filtration in the ionic range.

Anhydrous:  Devoid of water.

Animal Dander:  Small scales, analogous to dandruff, that comes from the skin, hair or feathers of animals or birds that contain a potent allergen that can cause allergic reactions in sensitive individuals.

Anion:  Negatively charged ion, such as Cl–.

Anisotropic (asymmetric) Membrane:  A membrane in which the pore size and structure are not the same from one side of the membrane to the other.  Such membranes are usually considered “directional” because of the difference in flow characteristics depending on which side of the membrane faces the feed stream.

Annealing:  In the manufacturing of float glass, the process of controlled cooling done in a Lahr to prevent residual stresses in the glass.  Re-annealing is the process of removing objectionable stresses in glass by re-heating to a suitable temperature followed by controlled cooling.

Annoyance:  A general feeling of displeasure or adverse psychological reaction toward a source.  Associated with disturbance, distress and frustration.

Annual Consumption:  Annual consumption refers to the amount of electricity used by a consumer in one year and is typically measured in kilowatt-hours (kWh).  This information can be acquired from your electricity bill or by contacting your energy provider.

Annual Fuel Utilization Efficiency (AFUE):  A rating that denotes the efficiency of gas heating equipment.  It is the amount of heating your equipment delivers for every dollar spent on fuel.  A higher rating indicates more efficient equipment.  This rating is calculated in accordance with the Department of Energy test procedures.  A laboratory-derived efficiency for heating appliances that accounts for chimney losses, jacket losses, and cycling losses, but not distribution losses or fan/pump energy.

Annual Percentage Rate (APR):  Annual cost of credit over the life of a loan, including interest, service charges, points, loan fees, mortgage insurance, and other items.
Annual Return:  The yearly savings divided by the initial cost needed to achieve the savings, expressed as a percent.

Anode:  Positive terminal of electrolytic cell.

Anoxia:  Anoxia means a total lack of oxygen.  Often used interchangeably with hypoxia, which means a reduced supply of oxygen.

ANR:  ACRONYM – Atmosphere normale de reference.  The term ANR is not usually applied to cfm, it is the new European replacement for FAD and usually follows the metric measurement of air flow, such as Cu Meters per Minute.

ANSI:  American National Standards Institute.  This consensus body consists of volunteer safety professionals who create or revise documents on test requirements, procedural methods, and product specifications.  In the realm of safety, ANSI Z87.1 is for safety caps.  When a manufacturer meets these specifications, then the aforementioned “Z” logos can be placed on the product.  There is no verification of the product meeting the standard by ANSI.  A private nonprofit organization overseeing the development of voluntary consenses standards for products, services, processes, systems, and personnel in the United States.  The organization also coordinates U.S. standards with international standards so that American products can be used worldwide.

Antagonist:  When talking about drugs, this refers to a compound that opposes the activity of the cell receptors.

Anthracite:  A hard, black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and low percentage of volatile matter.

Anthrax:  An acute infectious disease caused by the spore-forming bacterium Bacillus anthracis.  Inhalation anthrax is usually fatal.  An infectious and usually fatal disease most commonly found in animals.  Recently, anthrax has been used on humans as a form of bioterrorism.

Anthropogenic:  Derived from human activities.

Anthropomorphic:  This term is used to describe a person’s attitude when he/she ascribes human attributes to an animal, or to the animal’s experiences or perceptions.

Anti-allergenic Air Filter (s):  “Most people are aware that outdoor air pollution can damage their health but may not know that indoor air pollution can also have significant effects. EPA studies of human exposure to air pollutants indicate that indoor air levels of many pollutants may be 2-5 times, and occasion more than 100 times, higher than outdoor levels. These levels of indoor air pollutants are of particular concern because it is estimated that most people spend as much as 90% of their time indoors.” Unlike outdoor air, indoor air is recycled again and again. This causes it to trap and build up pollutants. Common pollutants include dust, mold and spores, pollen, pet dander and smoke.  The human body has developed an intricate system for getting rid of harmful foreign substances such as bacteria and viruses. When one of these enters the body, the immune system begins to manufacture antibodies to fight it off.  Most people can breathe in pollen, dust, and dander with no problem. But for people who are allergic to these ordinary everyday things, these substances present more serious consequences. They set off a complicated chain reaction in which the body works hard to expel them. That’s why your nose runs, your eyes water, you sneeze and cough.  Air filters with permanently electrostatically charged fibers (like Nordic Pure’s) that work like magnets to attract and capture the particles in your air while maintaining the efficiency of your window unit.

• Improve the air quality in your home.
• Captures microscopic allergens like dust and smoke particles.
• Captures large allergens like mold spores, pet dander and pollen.
• Filters can last up to 3 months.

Nordic Pure’s Merv 12 anti-allergenic pleated air filters significantly reduce dust, mold spores, pet dander, pollen, smoke particles, and other indoor air contaminants by up to 97.8%. We’ll not only improve your indoor air quality, but you may be able to dust less and your allergies may not be as bad since you have less indoor air pollutants. Our filter media has a permanent electrostatic charge and does not support the growth of bacteria, fungi, mildew or mold. Prices include FREE SHIPPING on air filters. We manufacture any size 1", 2" and 4" HVAC filters and Honeywell Filter Replacements for FC100A1037 air filters / FC200E1037 air filters (20x25x5 filters) and FC100A1029 air filters / FC200E1029 air filters (16x25x5 filters). We also make custom size air filters with fast and free shipping, so order your custom air filters today and see what better air filters can do for you.

Anti Re-entrainment Sock:  The outer layer on a coalescing filter that prevents separated liquids from re-entering the air stream.  Also known as anti re-entrainment barrier.

Anti-allergenic:  Property of a device, substance or product which ensures no adverse reaction in people normally sensitized by allergies.

Antibodies:  Proteins in the blood that are generated in reaction to foreign proteins or polysaccharides; also called “immunoglobulins.”

Antibiotic:  Medication used to treat infection caused by bacteria.  Antibiotics do not protect against viruses and do not prevent the common cold.

Antibody (Ab):  An immunoglobulin molecule produced by B-lymphoid cells that combine specifically with an immunogen or antigen.  Antibodies may be present naturally, their specificity is determined through gene rearrangement or somatic replacement or may be synthesized in response to stimulus provided by the introduction of an antigen; antibodies are found in the blood and body fluids, although the basic structure of the molecule consists of two light and two heavy chains, antibodies may also be found as dimers, trimers, or pentamers.  After binding antigen, some antibodies may fix, complement, bind to surface receptors on immune cells, and in some cases may neutralize microorganisms.  See also: immunoglobulin.  Syn: immune protein, protective protein, sensitizer (2).

Anticholinergics:  (Also called cholinergic blockers or “maintenance” bronchodilators).  This type of medicine helps open (dilate) the bronchial tubes (airways) to help move more air easily into and out of the lungs.  Anticholinergics also help clear mucus from the airways.  As the airways open, the mucus moves more freely and can therefore be coughed out more easily.  Anticholinergics work differently and more slowly than fast-acting bronchodilators.

Anticipation:  To realize in advance, i.e. – a heat anticipator on a thermostat is used to shut down a furnace prior to the set point, as we are anticipating that the furnace will continue to run until the heat exchange is cooled and we will be at set point buy that time.

Anti-degradation:  That portion of federal water quality requirements prohibiting deterioration where pollution levels are above the legal limit.

Antigen:  Pronunciation (an′ti-jen).  An antigen is a substance that, when introduced into the body, stimulates the production of an antibody.  Any substance that, as a result of coming in contact with appropriate cells, induces a state of sensitivity or immune responsiveness and that reacts in a demonstrable way with antibodies or immune cells of the sensitized subject in vivo or in vitro.  Modern usage tends to retain the broad meaning of antigen, employing the terms “antigenic determinant” or “determinant group” for the particular chemical group of a molecule that confers antigenic specificity.  See also: hapten.  Syn: immunogen.

Antihistamine:  Pronunciation (an′tē-his′tă-mēn).  Medication that prevents symptoms of congestion, watery eyes, sneezing, and itchy, runny nose by blocking histamine receptors.  Antihistamine refers to a variety of compounds that oppose the actions of histamine and are used especially for treating allergic reactions (as hayfever), cold symptoms, and motion sickness.  Many antihistamines can be purchased at your pharmacy without a prescription.  Drugs having an action antagonistic to that of histamine on either H1 or H2 receptors.

Anti-inflammatory Medicines:  Used to prevent symptoms by keeping airways from swelling when exposed to triggers.  Medication, such as prednisone, aspirin or steroids, that reduces inflammation and swelling.

Antimicrobial:Agent that kills microbial growth.  See “disinfectant,” “sanitizer,” and “sterilizer.”

Antineoplastic:  A substance that blocks the formation of neoplasms (growths that may become cancerous).  See Cytotoxic drugs.

Anti-Pulsation Tank:  Sometimes called a pulsation damper this is a small receiver fitted on the inlet or discharge of a reciprocating compressor.  The device is designed to remove the resonance from the compressor thereby reducing noise.

Anti-rejection Drugs:  People who have received an organ transplant need medication every day to prevent organ rejection.  Drugs called immunosuppressants or anti-rejection drugs help suppress the immune system to prevent or reverse rejection.  At the same time, these drugs may have side effects.  A number of drugs are commonly used for this purpose.

Anti-Scald:  A valve that restricts water flow to help prevent burn injuries.  See Pressure Balancing Valve and Thermostatic Valve.  In some areas, plumbing codes require anti-scald valves.  Speak to a professional in your area for more information and help with code requirements.

Anti-Siphon:  A device that prevents waste water from being drawn back into supply lines and possibly contaminating the water supply.

Anti-Stat:  Describes any product or item which by design, prevents the build-up of static electricity and/or dissipates static electricity.

Antistatic:  A condition inherent in or applied to a material usually fabric or plastic, which results in a significant reduction in or the absence of electrical charges.  (An electrical resistivity of ~10-10ohm/square or higher.)

Anti-Walk Blocks:  Elastomeric blocks that limit lateral glass movement in the glazing channel which may result from thermal, seismic, wind load effects, building movement, and other forces that may apply.

Antiquated:  No longer in use, useful or functioning, as in most home inspection associations.  Obsolete.

Anxiolytic:  Removing or diminishing anxiety.

Any Size Air Filters Online:  Nordic Pure’s Merv 12 anti-allergenic pleated air filters significantly reduce dust, mold spores, pet dander, pollen, smoke particles, and other indoor air contaminants by up to 97.8%. We’ll not only improve your indoor air quality, but you may be able to dust less and your allergies may not be as bad since you have less indoor air pollutants. Our filter media has a permanent electrostatic charge and does not support the growth of bacteria, fungi, mildew or mold. Prices include FREE SHIPPING on air filters. We manufacture any size 1", 2" and 4" HVAC filters and Honeywell Filter Replacements for FC100A1037 air filters / FC200E1037 air filters (20x25x5 filters) and FC100A1029 air filters / FC200E1029 air filters (16x25x5 filters). We also make custom size air filters with fast and free shipping, so order your custom air filters today and see what better air filters can do for you.  You may either call us directly at 800-590-0339 during normal business hours or order in the privacy of your home online 24 hours a day.

Any Size Custom Pleated Air Filters:  Our MERV12 anti-allergenic pleated air filters significantly reduce dust, mold spores, pet dander, pollen, smoke particles, and other indoor air contaminants by up to 97.8%. We'll not only improve your indoor air quality, but you may be able to dust less and your allergies may not be as bad since you have less indoor air pollutants. Our filter media has a permanent electrostatic charge and does not support the growth of bacteria, fungi, mildew or mold. Prices include FREE SHIPPING on air filters. We manufacture any size 1", 2" and 4" HVAC filters and Honeywell Filter Replacements for FC100A1037 air filters / FC200E1037 air filters (20x25x5 filters) and FC100A1029 air filters / FC200E1029 air filters (16x25x5 filters). We also make custom size air filters with fast and free shipping, so order your custom air filters today and see what better air filters can do for you.

Any Size Order Air Filter:  Our MERV12 anti-allergenic pleated air filters significantly reduce dust, mold spores, pet dander, pollen, smoke particles, and other indoor air contaminants by up to 97.8%. We'll not only improve your indoor air quality, but you may be able to dust less and your allergies may not be as bad since you have less indoor air pollutants. Our filter media has a permanent electrostatic charge and does not support the growth of bacteria, fungi, mildew or mold. Prices include FREE SHIPPING on air filters. We manufacture any size 1", 2" and 4" HVAC filters and Honeywell Filter Replacements for FC100A1037 air filters / FC200E1037 air filters (20x25x5 filters) and FC100A1029 air filters / FC200E1029 air filters (16x25x5 filters). We also make custom size air filters with fast and free shipping, so order your custom air filters today and see what better air filters can do for you.

Any Size Pleated Air Filters:  Our MERV12 anti-allergenic pleated air filters significantly reduce dust, mold spores, pet dander, pollen, smoke particles, and other indoor air contaminants by up to 97.8%. We'll not only improve your indoor air quality, but you may be able to dust less and your allergies may not be as bad since you have less indoor air pollutants. Our filter media has a permanent electrostatic charge and does not support the growth of bacteria, fungi, mildew or mold. Prices include FREE SHIPPING on air filters. We manufacture any size 1", 2" and 4" HVAC filters and Honeywell Filter Replacements for FC100A1037 air filters / FC200E1037 air filters (20x25x5 filters) and FC100A1029 air filters / FC200E1029 air filters (16x25x5 filters). We also make custom size air filters with fast and free shipping, so order your custom air filters today and see what better air filters can do for you.

AP:  ACRONYM – Air pressure.

APA Plywood:  (APA=American Plywood Association).  Plywood that has been rated by the American Plywood Association.  For example, number one APA rated exterior plywood contains no voids between laminate layers.

APC:  Association des professionnels du chauffage.  An association of professionals of the heating industry in Quebec that offers information to industry and consumers and that helps develop safety standards and installation codes and offers training and inspections for different heating systems.

Aperture:  The opening in pipes.

Aperture Size:  See Mesh Opening.

APF:  Assigned Protection Factor.  This is a numerical value assigned to a specific class of respiratory, and represents by increasing value, the relative protection that the type of device affords when its fit is verified by fit testing.

A.P.I.:  American Petroleum Institute.

Apnea:  Absence of breathing for more than 10 seconds.  See also sleep apnea.

Appliance:  A household device operated by use of electricity or gas.  Not included in this definition are components covered under central heating, central cooling or plumbing.

Appraisal:  An expert valuation of property.

Approach:  The area between the sidewalk and the street that leads to a driveway or the transition from the street as you approach a driveway.

Appropriative Rights:  “First in time, first in right” principle that developed from the gold miners in 1849.  Water claims were staked out by posting notice.

APR:  Air-purifying respirator means a respirator with an air-purifying filter, cartridge, or canister that removes specific air contaminants by passing ambient air through the air-purifying element.

April Air Filters:  See Aprilaire.

Aprilaire:  To help you protect the health and comfort of your family, the only truly effective solution is a whole-house solution. That’s why Aprilaire considers your entire home when creating indoor air quality solutions for your home.  Choose one of the multiple Aprilaire products for healthier, fresher and cleaner indoor air every day of every year.

• Home Air Purifiers
• Furnace Humidifiers
• Home Ventilation System  
• Central Dehumidifiers 
• Electronic Thermostats
• Zone Control Systems

Aprilaire IAQ Specialist:  An HVAC contractor that has been trained by Aprilaire on installations and applications of Aprilaire Indoor Air Quality (IAQ) products.

Apron:  A trim board that is installed beneath a window sill.

AQMS:  Air Quality Management System.

Aquaculture:  The art of cultivating the natural produce of water; the raising or fattening of fish in enclosed ponds.
Aquastat:  A heating control device that controls the burner or the circulator in a hydronic heating system.

Aqua-Surger:  UAS’ proprietary, in-place cleaning system associated with SMOG-HOG electrostatic precipitators.  Consists of fixed face and overhead cleaning nozzles and associated detergent injection equipment.

Aqueous:  (a.) Of, relating to, or resembling water.  (b.) Water-based.  In reference to solution made in water.

Aquifer:  Saturated layer of rock or soil below the ground surface that can supply usable quantities of groundwater to wells and springs, and be a source of water for domestic, agricultural, and industrial uses.  Any underground formation that stores, transmits and yields water to wells and springs.

Aquifer, Confined:  An aquifer that is overlain by a confining bed.  The confining bed has a significantly lower hydraulic conductivity than the aquifer.

Aquifer, Unconfined:  An aquifer in which there are no confining beds between the zone of saturation and the surface.  There will be a water table in an unconfined aquifer.

Aquitard:  Low-permeability geologic formation that bounds an aquifer.

Arbitration Service:  A service to resolve complaints, as in NACHI’s Arbitration Service.

Architect:  A tradesman who designs and produces plans for buildings, often overseeing the building process.

Architects Rule (Ruler):  Three sided ruler with different scales on each side.  Also referred to as a “scale.”

Architectural Service:  Any practice involving the art and science of building design for construction of any structure or grouping of structures and the use of space within and surrounding the structures or the design, design development, preparation of construction contract documents, and administration of the construction contract.

Area and Other Sources:  Include sources that generally have smaller emissions on an individual basis than “major sources” and are often too small or ubiquitous in nature to be inventoried as individual sources.  “Area sources” include facilities that have air toxics emissions below the major source threshold as defined in the air toxics sections of the Clean Air Act and thus emit less than 10 tons of a single toxic air pollutant or less than 25 tons of multiple toxic air pollutants in any one year.  Area sources include smaller facilities, such as dry cleaners.  “Other sources” include sources such as wildfires and prescribed burnings that may be more appropriately addressed by other programs rather than through regulations developed under certain air toxics provisions (section 112 or 129) in the Clean Air Act.  For example, wildfires and prescribed burning are being addressed through the burning policy agreed to by the Interim Federal Wildland Policy.

Area Source:  Any small source of non-natural air pollution that is not large enough to be classified as a major source or point source.  Any source of air pollution that is released over a relatively small area but which cannot be classified as a point source.  Such sources may include vehicles and other small engines, small businesses and household activities, or biogenic sources such as a forest that releases hydrocarbons.  May be referred to as nonpoint source.

Area Sources:  Those sources for which a methodology is used to estimate emissions.  This can include area-wide, mobile and natural sources, and also groups of stationary sources (such as dry cleaners and gas stations).  The California Clean Air Act requires air districts to include area sources in the development and implementation of the AQMP. In the California emission inventory all sources which are not reported as individual point sources are included as area sources.  The federal air toxics program defines a source that emits less than 10 tons per year of a single hazardous air pollutant (HAP) or 25 tons per year of all HAPs as an area source.

Area Wells:  Corrugated metal or concrete barrier walls installed around a basement window to hold back the earth.

Areas of Special Biological Significance (ASBS):  Thirty-four locations along California coast and offshore islands that the State Water Board has officially designated as having unique biological value and/or fragility.

Areaway:  An open subsurface space adjacent to a building used to admit light/air or as a means of access to a basement.

Area-Wide Sources:  Sources of pollution where the emissions are spread over a wide area, such as consumer products, fireplaces, road dust and farming operations.  Area-wide sources do not include mobile sources or stationary sources.

ARI (Air-Conditioning and Refrigeration Institute):  Acronym for the Air Conditioning and Refrigeration Institute.  Air-Conditioning and Refrigeration Institute is a nonprofit, voluntary organization comprised of heating, air conditioning and refrigeration manufacturers.  ARI publishes standards for testing and rating heat pumps and air conditioners to provide you with a standardized measure of comparison.  So, ARI ensures a level of performance within the industry.

Arizona Road Dust:  Standardized test dusts for both liquid and air classified from natural Arizona dust generally referred to an A.C. Fine and A.C. Course Dust.  Both dust materials also carry an ISO designation and have a standardized size distribution of particles.

Aromatic:  A type of hydrocarbon, such as benzene or toluene.  Some aromatics are toxic.

Array:  An array is the arrangement of internal components in a bank, expressed as the number of components across the width of a bank times the number high (e.g., a 4 by 3 array of HEPA filters).

Arrestance:  A measure of the ability of an air-filtration device to remove synthetic dust from the air.  The percentage weight of ASHRAE dust caught by the filter compared to the total weight of dust fed into the filter throughout the filter test.

Arsenic:  A highly poisonous semi-metallic element.  According to a 1999 study by the National Academy of Sciences, arsenic can cause bladder, lung, and skin cancer and may cause kidney and liver cancer.  The study also found that arsenic harms the central and peripheral nervous systems, as well as heart and blood vessels, and causes serious skin problems.  It also may cause birth defects and reproductive problems.  These health impacts are caused when arsenic contaminates drinking water supplies.  It enters water supplies either from natural deposits in the earth or from industrial and agricultural pollution.

Arterial Blood Gas Test:  A blood test that measures oxygen and carbon dioxide in the blood.

Arterial Hypoxia:  Hypoxia caused by a reduction in oxygen supply to the cells in tissue due to the reduced partial pressure of oxygen in the blood; for example, hypoxia caused by reduced atmospheric pressure at high elevations.

Artesian Well:  A well in which the water rises above the top of the aquifer, whether or not it flows out at the land surface.  Sometimes restricted to mean a flowing artesian well.

Artesian Well, Flowing:  An artesian well whose head [pressure] is sufficient to raise the water above the land surface.

Arthritis:  Inflammation of the body joints.

Artificial Demand:  Running a compressed air system at a higher than needed pressure.

Asbestos:  A common form of magnesium silicate which was used in various construction products due to its stability and resistance to fire.  Asbestos exposure (caused by inhaling loose asbestos fibers) is associated with various forms of lung disease.  The name given to certain inorganic minerals when they occur in fibrous form.  Though fire-resistant, its extremely fine fibers are easily inhaled, and exposure to them over a period of years has been linked to cancers of the lung or lung-cavity lining and to asbestosis, a severe lung impairment.  A naturally occurring mineral fiber sometimes found in older homes.  It is hazardous to your health when a possibility exists of exposure to inhalable fibers.  Homeowners should be alert for friable (readily crumbled, brittle) asbestos and always seek professional advice in dealing with it.

Asbestos Abatement:  Procedures to control fiber release from asbestos-containing materials in a building or to remove them entirely, including removal, encapsulation, repair, enclosure, encasement, and operations and maintenance programs.

Asbestos Remediation:  The process of safely removing asbestos from indoor environments.  High quality, high filtration vacuum cleaners are often used in this process.  Sometimes referred to as Asbestos Abatement.

Aseptic:  Refers to an operation performed in a sterile environment designed to prevent contamination through introduction of bacteria.

Aseptic Technique:  The performance of a procedure or operation in a manner that prevents the introduction of septic material.

Ash:  Impurities consisting of silica, iron, alumina, and other noncombustible matter that are contained in coal.  Ash increases the weight of coal, adds to the cost of handling, and can affect its burning characteristics.  Ash content is measured as a percent by weight of coal on an “as received” or a “dry” (moisture-free, usually part of a laboratory analysis) basis.

ASHRAE:  A leading HVAC/R Association – American Society of Heating, Refrigerating and Air Conditioning Engineers – http://www.ashrae.org/.  The organization which historically set standards for low and medium efficiency air filters.  ASHRAE is based in Atlanta, Georgia, USA, and is an international membership organization operated for the exclusive purpose of advancing the arts and sciences of heating, refrigeration, air conditioning and ventilation, the allied arts and sciences, and related human factors for the benefit of the public.

ASHRAE/ANSI Standard 55:  A temperature standard proposed by the American Society of Heating, Refrigeration and Air-conditioning Engineers formerly based on the Gagge’s Standard Effective Temperature, but due to come in line with ISO7730 (see below) in using Fanger’s PMV/PPD.

ASHRAE 52.1:  Test standard for filters that measures pressure drop, arrestance, dust spot efficiency, and dust holding capacity.

ASHRAE 52.2:  Test standard that measures the fractional particle size efficiency of a filter and assigns a MERV depending on the particle size efficiency in three different particle size ranges.

ASHRAE Scale:  A set of seven descriptors of subjective warmth.  Usual wording is:  Cold (-3), cool (-2), slightly cool (-1), neutral (0), slightly warm (+1), warm (+2), and hot (+3).

ASHRAE Standards:  The ASHRAE Handbook is a four-volume resource for HVAC&R technology and is available in both print and electronic versions. The volumes are Fundamentals, HVAC Applications, HVAC Systems and Equipment, and Refrigeration. One of the four volumes is updated each year.  ASHRAE also publishes a well recognized series of standards and guidelines relating to HVAC systems and issues. These standards are often referenced in building codes. Examples of some ASHRAE Standards are:

• Standard 34 – Designation and Safety Classification of Refrigerants
• Standard 55 – Thermal Environmental Conditions for Human Occupancy
• Standard 62.1 – Ventilation for Acceptable Indoor Air Quality (versions: 2001 and earlier as "62", 2004 and beyond as "62.1")
• Standard 62.2 - Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings
• Standard 90.1 - Energy Standard for Buildings Except Low-Rise Residential Buildings
• Standard 135 – BACnet - A Data Communication Protocol for Building Automation and Control Networks

These and many other ASHRAE Standards are periodically reviewed, revised, and published, so the year of publication of a particular standard is important for code compliance.
The ASHRAE Journal is a monthly magazine published by ASHRAE. It includes peer-reviewed articles on the practical application of HVAC&R technology, information on upcoming meetings and product shows, classified and display advertising, and editorials. Members of ASHRAE receive the magazine and the current year's volume of the ASHRAE Handbook as membership benefits. ASHRAE also publishes many books, ASHRAE Transactions, and the International Journal of HVAC&R Research.

ASHRAE Standard 62:  Ventilation for Acceptable Indoor Air Quality.  Details two methods for compliance:  Ventilation Rate Procedure and the Indoor Air Quality Procedure.  Rapidly becoming the standard of care for building ventilation and indoor air quality.

ASL:  ACRONYM – Above sea level.

ASME:  American Society of Mechanical Engineers.  Published code, which governs the design of pressure housings.

Aspect Ratio:  The ratio of the width to the length. AR = W/L.  The ratio of length to width of a rectangular air grill or duct.

Aspergillosis:  A group of diseases caused by the fungus Aspergillus; affected tissues may include lungs, bronchial airways, sinus cavities, ears, and eyes.

Asphalt:  A dark brown to black highly viscous hydrocarbon produced from the residue left after the distillation of petroleum.  Asphalt is used on roofs and highways as a waterproofing agent.

Asphalt Plastic Cement:  An asphalt-based cement used to bond roofing materials.
Asphyxiant:  A vapor or gas which can cause unconsciousness or death by suffocation (lack of oxygen).  Asphyxiation is one of the principal potential hazards of working in confined spaces.

Aspiration:  The movement is a fluid produced by suction.

Assay:  Analytical procedure to determine purity or concentration of a specific substance in a mixture.

Assessment:  A tax levied on a property, or a value placed on the worth of a property.

Assigned Protection Factor (APF):  The anticipated level of respiratory protection that would be provided by a properly functioning respirator to properly fitted and trained user.

Assimilative Capacity:  The capacity of a natural body of water to receive (a) wastewaters, without deleterious effects, (b) toxic materials, without damage to aquatic life or humans who consume the water, (c) BOD, within prescribed dissolved oxygen limits.

Assigned Protection Factor (APF):  The workplace level of respiratory protection that a respirator or class of respirators is expected to provide to employees when the employer implements a continuing, effective respiratory protection program.

Associate Member:  An indentured servant.  Beginning level of inspection association membership.  Slave.  See Candidate.

Asthma:  Asthma is a chronic inflammatory disorder in which many cells play a role, in particular mast cells, Eosinophils, and T lymphocytes. In susceptible individuals this inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough particularly at night and/or in the early morning.  These symptoms are usually associated with widespread, but variable, airflow limitation that is at least partly reversible either spontaneously or with treatment.  The inflammation also causes an associated increase in airway responsiveness to a variety of stimuli.  Asthma is a “disorder” rather than a “disease.”  Many factors contribute to airflow limitation in asthma, each related to the inflammatory process; these factors may vary within and between individuals.  A condition marked by recurrent attacks of difficult or labored breathing and wheezing resulting from spasmodic contraction and hypersecretion of the bronchi.  It is caused by exposure to allergens such as drugs, foods, environmental pollutants, or intrinsic factors.  The danger with asthma is that the chest constriction can result in lack of oxygen getting to the person’s body and brain.  Asthma can be life threatening if not managed correctly.

Asthma, Chronic:  A disease of the air passages that carry air in and out of the lungs.  Asthma causes the airways to narrow, the lining of the airways to swell and the cells that line the airways to produce more mucus.  These changes make breathing difficult and cause a feeling of not getting enough air into the lungs.  Common symptoms include shortness of breath, wheezing and excess mucus production.

Asthma Specialist:  Health care professional who has received specific training in the diagnosis and management of asthma.

Asthma Triggering Irritants:  The medical condition of asthma can be triggered by a number of irritants including allergens such as dust mites, animal dander and cockroaches, certain foods, strong fumes, irritants like cigarette smoke, smog, soot or pollen, respiratory infections, cold or windy weather conditions, and emotions or exercise that cause deep or rapid breathing.

ASTM:  American Society for Testing and Materials.  A technical organization that develops standards on characteristics and performance of materials, products, systems and services.  It is the world’s largest source of voluntary consensus standards.  A nonprofit organization that provides a forum for producers, consumers, and representatives of government and industry, to write laboratory test standards for materials, products, systems, and services.  ASTM publishes standard test methods, specifications, practices, guides, classifications, and terminology.

Astragal:  A molding which is attached to one of a pair of swinging doors against which the other door strikes.

Asymmetric Membrane:  A membrane in which the pore size and structure are not the same from one side of the membrane to the other. These membranes are usually considered directional because of difference in flow characteristics depending on which side of the membrane faces the feed stream.

ATA:  ACRONYM – Atmospheres absolute.  It is the weight of the column of air existing above the earth’s surface at 45° Lat and sea level.  Is equivalent to 14.696 psiA or 1.0333 kg/sq cm.  Equals atmospheres gauge plus 1.

Atelectasis:  Partial or complete collapse of the lung, usually due to a blockage of the air passages with fluid, mucus or infection.  Symptoms include dry cough, chest pain and mild shortness of breath.

Atmosphere (ATM):  The standard atmosphere is defined as the pressure exerted by a column of mercury 760 mm high with a density of 13,595 g/cm³ at the standard acceleration due to gravity of 9.8 m/s².  The 760th part of this pressure unit is the torr.  The technical atmosphere (at) denotes the pressure of a force of 1 kg acting on an area of 1 cm².  A standard unit of pressure exerted by a 29.92-inch column of mercury at sea level and equal to 1000 grams per square centimeter.  The gaseous mass or envelope of air surrounding the Earth.  From ground-level up, the atmosphere is further subdivided into the troposphere, stratosphere, mesosphere, and the thermosphere.

Atmospheric Boundary Level:  A region near the earth in which the relative velocity increases from zero with elevation, due to the motion of the atmosphere relative to the earth’s surface.

Atmospheric Condenser:  A condenser operated with water that is exposed to the atmosphere.

Atmospheric Dew Point:  Is the temperature at which water vapor begins to condense at atmospheric pressure.  Is the same as dew point, but is related to atmospheric air only.

Atmospheric Dispersion:  The atmosphere’s capacity to dilute the concentration of pollutants in the air.

Atmospheric Dust Spot Efficiency Test:  ASHRAE 52.1.  Standard test method that measures the ability of a filter to remove the staining portion of the atmospheric dust from the test air.

Atmospheric Inversion:  A term which describes the rising of warm air above cold air when two air masses of different temperatures, humidity and pressure meet.

Atmosphere-supplying Respirator:  A respirator that supplies the respirator user with breathing air from a source independent of the ambient atmosphere, and includes supplied-air respirators (SARs) and self-contained breathing apparatus (SCBA) units.

Atmospheric Pressure:  The air pressure of the atmosphere at a specific elevation or altitude; the measurement of this can be expressed in kPa, psi, mmHg or other units.  At sea level there is 14.7 psig also written as 29.92" Hg or approximately 14.7 PSI; 407" water gauge.  Airflow is the result of a difference in pressure (above or below atmospheric) between two points.

Atom:  Smallest particle of an element capable of entering into a chemical reaction.

Atomize:  The breaking-up of paint into fine particles or droplets by a paint gun using compressed air.

Atopic Asthma:  Asthma characterized by atopy.

Atopy:  The state of having one or more of a defined group of diseases-allergic rhinoconjunctivitis, allergic asthma, and atopic dermatitis-that are caused by a genetic propensity to produce immunoglobulin E (IgE) antibodies to environmental allergens encountered through inhalation, ingestion, and possibly, skin contact.  A broader definition, sometimes used for epidemiologic studies, requires only the presence of IgE antibody, regardless of allergic disease.

Attached Sunspace:  Solar collector that doubles as useful building space also attached greenhouse, solarium.  The term ‘attached’ specifically implies a space that shares one common wall with the associated building, such as a conservatory.

Attack:  See: Episode.

Attainment Area:  A geographic area in which levels of a criteria air pollutant meet the health-based primary standard (National Ambient Air Quality Standard, or NAAQS) for the pollutant.  An area may have on acceptable level for one criteria air pollutant, but may have unacceptable levels for others.  Thus, an area could be both attainment and nonattainment at the same time.  Attainment areas are defined using federal pollutant limits set by regulatory agencies (EPA).

Attention Level:  A guideline established by the Central Coast Regional Water Quality Control Board to identify the concentration of a substance in a particular medium (water, soil, etc.) that may be of concern when exceeded.  If contaminants are found at concentrations above their attention levels, measures should be taken to address the pollution.

Attenuation:  Reduction of the signal power or field strength as a function of distance through a material.  Also refers to shielding effectiveness.

Attic:  The usually unfinished space above a ceiling and below a roof.

Attic Access:  An opening that is placed in the dry-walled ceiling of a home providing access to the attic.

Attic Fan:  A fan mounted on an attic wall used to exhaust warm attic air to the outside.

Attic Insulation:  The installation of approved insulation products (rockwool, fiberglass, and cellulose) evenly across the unconditioned attic area to achieve desired levels of thermal resistance.  Insulation products have manufacturer rated “R” levels (resistance to heat loss measurements).  The more inches of insulation installed the higher the resistance level.  The recommended “R” values vary by climatic regions of the country.  It is common for weatherization programs to install a minimum of R-19 or as much as R-38 in colder regions.  The cost-effective level of insulation to be added, if any, depends on the existing level of insulation in the attic.  Auditors determined the amount of insulation to be added through prescriptive lists or energy audit programs that calculate the saving to investment ratio from increasing insulation levels.

Attic Preparation:  This refers to the protocol for inspecting and preparing an attic area for the installation of insulation.  The preparatory work is directed primarily to air infiltration and safety issues.  Some of the protocols include placing barriers around heat-producing sources in the attic (electrical junction boxes, recessed lights, etc.); placing chutes by the eaves to prevent the insulation from blocking needed air ventilation paths; and sealing bypasses and other penetrations between the heated space and the unconditioned attic area.

Attic Vent:  HVAC term for a passive or mechanical device used to ventilate an attic space, primarily to reduce heat buildup and moisture condensation.

Attic Ventilators:  In houses, screened openings provided to ventilate an attic space.  They are located in the soffit area as inlet ventilators and in the gable end or along the ridge as outlet ventilators.  They can also consist of power-driven fans used as an exhaust system.

Attrition:  Wearing or grinding down by friction.  One of the three basic contributing processes of air pollution; the others being vaporization and combustion.

Audit:  The process of identifying energy conservation opportunities in buildings.

Auger:  In carpentry, a wood-boring tool used by a carpenter to bore holes.

Augmentation:  In fabric air filtration, the imposition of an electrical field to the collecting surface and/or subjecting the incoming particulate matter to a charging process.

Authority Having Jurisdiction:  An agency established by a provincial, federal, or territorial government, that has the responsibility for occupational health and safety legislation.

Authority to Construct (A/C):  A pre-construction permit issued by an air district.

Auto Changeover:  A control package that provides for automatic switching from a primary air conditioning system to a backup in the event of a failure of the primary system.

Autoclave (ing):  A chamber for sterilizing with saturated steam filters or equipment by using constant high temperature and pressure (121ºC, 15 psi).  One method of  (“terminal”) sterilization using saturated steam.

Auto Defrost (De-icer):  When dehumidifiers work at low ambient temperatures, frost can build up on the refrigeration coils, rendering the dehumidifier ineffective.  An auto defrost may work by turning the unit off for a period of time or by routing hot compressor gasses to thaw the coils for continual operation.  See “Hot Gas Defrosting.”

Automatic Control:  Controls that react to a change in conditions to cause the condition to stabilize.

Automatic Cord Winder:  Allows rewinding of the electrical cord by pressing a button.  Adds some weight to the unit.

Automatic Darkening Welding Filter:  An optical filter that automatically switches from a light state to a dark state (shade) in response to change in incident light intensity.

Automatic Dust Bag Closure:  Many high-filtration, high quality vacuum cleaner manufacturers such as Miele, Sebo and others have designed their paper dust bags so that when they are removed from the vacuum cleaner for disposal a rolling shutter or other device seals the bag so dust and soils cannot escape during the disposal process.

Automatic Expansion Valve:  A pressure actuated metering device to regulate the flow of refrigerant into the evaporator according to the evaporator pressure.

Automatic Sequencer:  A device which operates compressors in sequence according to a programmed schedule.

Automatic Setting:  This is a unique power setting available on certain Miele canisters such as the Champagne that allows the vacuum cleaner to sense the suction required and automatically adjust the motor speed.

Autotrophic Organisms:  Bacteria that thrive by using inorganic materials for energy and growth.

Auxiliary Heating:  The conventional (i.e. non-solar) contribution to the total load (e.g. gas boiler etc.).

Auxiliary Power Unit (APU):  APUs provide a larger array of comfort features for drivers looking to reduce idling.  APUs can provide heat, air conditioning, power for household electrical devices and engine heat.  Most devices combine a small heater, a compressor for air conditioning and an alternator.  APUs may be powered by diesel fuel directly from the tractor fuel tank, or by a bank of rechargeable batteries.  Diesel driven APUs can operate for 5 hours or more on a single gallon of diesel fuel.  Costs for these devices can range from $3500 to $9000, but are typically in the $6000 to $7000 range.  For locomotives APUs automatically shut down the main locomotive engine idle while maintaining all vital main engine systems at greatly reduced fuel consumption.

Available Heat:  The amount of heat energy that may be converted into useful energy from a fuel.

AVC:  Assurance of Voluntary Compliance.

Avogadro’s Law:  States that equal volumes of all gases under the same conditions of pressure and temperature contain the same number of molecules.

AWG:  American Wire Gauge.

Awning:  An exterior, movable and usually flexible sun shading device.  Protects by deflecting or diffusing solar radiation at certain angles.

Awning Window:  A window with hinges at the top allowing it to open out and up.

Axenic:  Completely germ free.  An axenic rat in an isolator would be one that is free of all other microorganisms.

Axial Compressor:  A compressor belonging to the group of dynamic compressors.  Characterized by having its flow in the axial direction.

Axial Fan:  A fan that has a set of fan blades mounted on a rotating shaft such as found on a common house fan or ceiling fan.

Axial Flow:  In-line air movement parallel to the fan or motor shaft.

Azeotropes:  Refrigerants that are mixtures or blends of different refrigerants that are at the same ratio in vapor as well as in liquid state.

Azeotropes - (Near):  A zeotrope having a temperature glide sufficiently small that it is inconsequential.

Azeotropic Mixture:  A combination of different refrigerants to mask one with desirable refrigerant properties, an example of this is R-502 witch is a mixture of 48.8% R-22 and 51.2% R-115.