February 2004
TYPES OF AIR POLLUTANTS
Government agencies—and consequently
the rest of us—divide air pollutants into two categories
as follows.
• Criteria
Air Pollutants (CAPs) - CAPs are the primary ingredients
of the most easily observed air pollution - urban smog and
soot. They are the 6 most common air pollutants: Carbon
Monoxide; Lead; Nitrogen Dioxide; Ozone (formed from precursor
Volatile Organic Compounds); Particulate Matter; and Sulfur
Dioxide. Because they are among the most regularly monitored
air pollutants, CAPs data tend to be relatively easy to
obtain. (Check out http://www.scorecard.org/env-releases/cap/
or http://www.epa.gov/air/criteria.html
for more information on CAPs).
• Hazardous Air Pollutants
(HAPS) - HAPs are the air-borne chemicals that can
cause adverse effects to human health or the environment.
Almost 200 of these chemicals have been identified, including
chemicals that can cause cancer or birth defects. Concentrations
of HAPs in ambient air (how much is in the air in a given
place at a given time) are not often regularly monitored.
(Check out http://www.scorecard.org/env-releases/def/hap_gen.html
or http://www.epa.gov/ttn/atw/index.html
for more information on HAPs)
