Area Source

A collection of similar seemingly small sources of pollution from throughout the non-attainment area. Examples include lawn mowers, barbecue grills, and fireplaces.

Alternative Fuels

Any motor fuel other than ordinary gasoline, especially those that result in lower levels of air pollutants (e.g. reformulated gasoline, natural gas, and liquid propane).

AQI

Acronym for Air Quality Index. The EPA (Environmental Protection Agency) developed the AQI to make reading ambient air data more understandable to the general public. When ambient air data is collected, the numbers are converted from their concentration levels into...

AirCare Colorado

The emissions testing program for the state of Colorado. See www.aircarecolorado.com for more details.

Aerosol

Tiny particles dispersed in gases. Often used synonymously with particulate matter (PM).