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Air Quality Trends

Air Quality Trends Quick Finder
Graph showing declining air pollution concentrations for lead
Air pollution concentrations for lead have declined.... Other air quality trends are detailed in the links below.
The U.S. Environmental Protection Agency 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)
* Lead (Pb)
* Nitrogen Dioxide (NO2)
* Ozone (O3)
* Particulate Matter (PM2.5)
* Particulate Matter (PM10)
* Sulfur 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.

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