Arrestance efficiency|the amount of dist that is removed by an air filter.
Biological contaminants|airborne agents such as bacteria, fungi, viruses, algae, insect parts, pollen, and dust
Building-related illness|a situation in which the symptoms of a specific illness can be traced directly to airborne contaminants. 
Environmental tobacco smoke (ETS)|combination of side-stream smoke from the burning end of a cigarette, cigar, or pipe and the exhaled mainstream smoke from the smoker.
Formaldehyde|a colorless, pungent byproduct of hydrocarbons that can cause irritation of the eyes and upper air passages.
Friable|the condition in which materials can release particulates into the air.
(HEPA) filter|an extended media, dry-type _______ mounted in a rigid frame. 
Multiple chemical sensitivity (MCS)|a medical condition found in some individuals who are vulnerable to exposure to certain chemicals and/or combinations of chemicals. 
New building syndrome|a condition that refers to indoor air quality problems in new buildings. 
Off-gassing|process by which furniture and other materials release chemicals and other volatile organic compounds into the air
Ozone|an unstable, poisonous oxidizing agent that has a strong odor and is irritating to the mucous membranes and the lungs. 
Pontiac fever|a mild form of Legionnaires’ disease.
Radon|a colorless, odorless, radioactive, and chemically inert gas that is formed by the natural breakdown of uranium in soil and groundwater.
Sick building syndrome|a condition that exists when more than 20% of a building’s occupants complain during a two-week period of a set of symptioms that are alleviated by leaving the building.
VOCs|a wide variety of compounds and chemicals found in such things as solvents, paints, and adhesives, which are released as gases at room temperature.