Air

So-called “pure” air is mixture of gases containing about 78 percent nitrogen; 21 percent oxygen;
less than 1 percent carbon dioxide, argon and other gases plus a varying amounts of water vapor.
 

Air Pollutants

Amounts of foreign and/or natural substances occurring in the atmosphere that may result in adverse effects on humans, animals, vegetation and/or materials.
 

Air Quality Index (AQI)

A numerical index used for reporting severity of air pollution levels to public. The AQI incorporates five criteria pollutants – ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide - into a single index.  AQI levels range from 0 (Good air quality) to 5OO (Hazardous air quality).
 

Air Quality Standard (AQS)

The prescribed level of pollutant in the outside air that should not be exceeded during a specific time period in order to protect public's health, established by both federal and state governments.
 

Air Toxins

A generic term referring to a harmful chemical or group of chemicals in the air. Substances that are especially harmful to health. Technically, any compound that is in the air and has potential to produce adverse health effects is an toxic.
 

Allergen

A substance capable of causing an allergic reaction because of an individual's sensitivity to that substance.
 

Biological Contaminants

Agents derived from, or that are, living organisms (e.g., viruses, bacteria. fungi, and mammal & bird antigens) that can be inhaled and can cause many types of health effects including allergic reactions, respiratory disorders, hypersensitivity diseases, and infectious diseases. Also referred to as “microbiologicals” or “microbials.” 
 

Building-Related Illness (DRI)

Diagnosable illness whose symptoms can be identified and whose cause can be directly attributed to airborne building pollutants (e.g., Legionnaire’s disease, hypersensitivity pneumonitis). Contrast with “Sick Building Syndrome”. 
 

CFM

Cubic feet per minute. The amount of air, in cubic feet, that flows through a given space in one minute. 1 CFM equals approximately 2 liters per second (l/s).
 

Conditioned Air

Air that has been heated, cooled, humidified, or dehumidified to maintain an interior space within the "comfort zone." (Sometimes referred to as “tempered” air.)
 

Environmental Illness (EI)

A term from diseases caused by the human-made environment we live in. Some diseases can have either natural or artificial causes.
 

Environmental Tobacco Smoke (ETS)

Mixture of smoke from the burning end of a cigarette, pipe, or cigar and smoke exhaled by the smoker also called secondhand smoke (SHS).
 

Fungi

Any of a group of parasitic lower plants that lack chlorophyll, including molds and mildews.
 

Hydrocarbons

Compounds containing various combinations of hydrogen and carbon atoms. They may be emitted into the air by natural sources (e.g., trees) or as a result of fossil and vegetative fuel combustion, fuel volatilization, and solvent use. Hydrocarbons are a major contributor to smog.
 

IAQ

Indoor Air Quality.
 

Multiple Chemical Sensitivity (MCS)

A condition wherein a person is sensitive or intolerant to a number of chemicals and other irritants at very low concentrations. (Distinct from "allergic")
 

Organic Compounds

Chemicals that contain carbon. Volatile Organic Compounds vaporize at room temperature and
pressure. They are found in many common household products and building materials.
 

PPM

Parts per million.
 

Particulate Matter (PM)

Solid or liquid particles of soot, dust, smoke, fumes, and aerosols.
 

Particulate Matter less than 10 microns (PMIO)

Tiny solid or liquid panicles of soot, dust, smoke, fumes, and aerosols. The size of the panicles (10
microns or smaller) allows them to easily enter the air sacs in the lungs where they may be deposited and result in adverse health effects. PMIO also causes visibility reduction and is a criteria air pollutant.
 

Particulate Matter equal or less than 2.5 microns (pM2.5)

Ultra-fine particles, or PM2.5 pose on increased health risk over PM 10 because PM2.5 can deposit deep in the lung and contain substances that are particularly harmful to human health. The United States Environmental Protection Agency promulgated national PM2.5 standards in 1997.
 

Radon (Rn) (and Radon Decay Products)

Radon is a radioactive gas formed in the decay of uranium. The radon decay products (also called radon daughters or progeny) can be breathed into the lung where they continue to release radiation as they further decay.
 

Reactive Organic Gas (HOG)

A photochemical reactive chemical gas composed of non-methane hydrocarbons that may contribute to the formation of smog. Also, sometimes referred to as Non-Methane Organic Gases (NMOGs).
 

Sick Building Syndrome (SBS)

Term that refers to a set symptoms that affect some number of building occupants during the time spent in the building and diminish or go away when they leave the building.
 

Smog

A combination of smoke and particulates including ozone, hydrocarbons, nitrogen oxides, and other chemically reactive compounds which, under certain conditions of weather and sunlight, may result in a murky brown haze that causes adverse health effects.
 

Soot

Very fine carbon particles that have a black appearance when emitted into the air.
 

Volatile Organic Compounds (V0Cs)

Compounds that vaporize (become a gas) at room temperature. Common sources include housekeeping and maintenance products, and building and furnishing materials.