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Pacific Southwest, Region 9
Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations
Air Quality Analysis
Air Quality Trends
Air Quality Trends Home
2008 Lead (Pb) National Standard
1978 Lead (Pb) National Standard
24-Hour Fine Particulate Matter (PM2.5)
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Air Quality Trends
US EPA sets National Ambient Air Quality Standards (NAAQS) for pollutants considered harmful to public health and the environment. There are NAAQS for six principal pollutants, which are called "criteria" pollutants: Carbon Monoxide (CO), Lead (Pb), Nitrogen Dioxide (NO2), Ozone (O3), Particulate Matter (PM2.5 and PM10), and Sulfur Dioxide (SO2).
The Air Quality Trends graphics show air pollution concentrations in Region 9 states since the establishment of each standard. In most areas, air quality has improved since the standards were established and in some cases, has improved dramatically.
The following graphs show these results:
Carbon Monoxide (CO)
2008 Lead (Pb) National Standard
1978 Lead (Pb) National Standard
8-Hour Ozone (O3)
24-Hour Sulphur Dioxide (SO2)
24-Hour Fine Particulate Matter (PM2.5)
Annual Fine Particulate Matter (PM2.5)
Particulate Matter (PM10)
Nitrogen Dioxide (NO2)
Annual Sulphur Dioxide (SO2)
For more information on air quality trends, see EPA Air Trends.
For information on the health effects of air pollution see EPA AIRNOW.