Acronyms

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

Please see www.epa.gov/airtrends for the latest information on Air Quality Trends.

Principal Pollutants:
CO Pb NO2, NOx O3 PM PM 2.5 PM-10 SO2, SOx	Carbon Monoxide Lead Nitrogen Dioxide, Nitrogen Oxides Ozone Particulate Matter Particulate Matter (2.5 micrometers in diameter or less) Particulate Matter (diameter of 10 micrometers or less) Sulfur Dioxide, Sulfur Oxides
CFCs	Chlorofluorocarbons
DU	Dobson Unit(s)
EPA	Environmental Protection Agency
FCCC	Framework Convention on Climate Change
HFCs	Hydrofluorocarbons
IPCC	Intergovernmental Panel on Climate Change
NAAQS	National Ambient Air Quality Standard
PAMS	Photochemical Assessment Monitoring Stations
NTI	National Toxics Inventory
PFCs	Perfluorinated Carbons
TRI	Toxic Release Inventory
TSP	Total Suspended Particulates
VOC	Volatile Organic Compounds