Bio-monitoring: The monitoring of a living organism, plant or animal, to measure its health and document any visible symptoms of coincident air quality effects.

Carbon Dioxide (CO2): A colorless, odorless gas that occurs naturally in the Earth's atmosphere. Significant quantities are also emitted into the air by fossil fuel combustion.

Carbon Monoxide (CO): A colorless, odorless gas resulting from the incomplete combustion of hydrocarbon fuels. CO interferes with the blood's ability to carry oxygen to the body's tissues and results in numerous adverse health effects. Over 80% of the CO emitted in urban areas is contributed by motor vehicles.

Chronic Exposure: Long-term exposure, usually lasting for a relatively long period of time (e.g. months or years).

Chronic Health Effect: A health effect that occurs over a relatively long period of time (e.g. months or years).

Greenhouse Gases: Atmospheric gases such as carbon dioxide, methane, chlorofluorocarbons, nitrous oxide, ozone, and water vapor that slow the passage of re-radiated heat through the Earth’s atmosphere.

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

Hydrogen Sulphide (H2S): A colorless, flammable, poisonous compound having a characteristic rotten-egg odor. About one third of the gas produced in Alberta contains H2S.

Inversion: The atmospheric property of temperature increasing with height.

Micron (mm): One one-millionth of a meter (1X 10-6 m)

Mobile Sources: Sources of air pollution such as automobiles, motorcycles, trucks, off-road vehicles, boats, and airplanes.