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Pacific Southwest, Region 9
Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, 147 Tribes
Air Quality Analysis
Air Quality Trends
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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)
For more information on air quality trends, see EPA Air Trends. For information on the health effects of air pollution see EPA AIRNOW.
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