Carbon Monoxide

National Trends in CO Levels
Local Trends in CO Levels

National Trends in CO Levels

Using a nationwide network of monitoring sites, EPA has developed ambient air quality trends for carbon monoxide (CO). Trends from 1980-2007 and from 1990-2007 are shown here. Under the Clean Air Act, EPA sets and reviews national air quality standards for CO. Air quality monitors measure concentrations of CO throughout the country. EPA, state, tribal and local agencies use that data to ensure that CO remains at levels that protect public health and the environment. Nationally, average CO concentrations have decreased substantially over the years. For information on CO standards, sources, health effects, and programs to reduce CO, please see www.epa.gov/air/urbanair/co.

Carbon monoxide air quality between 1980 and 2007, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 136 monitoring sites nationwide, with the average decreasing 76% from 1980 to 2007. Most of the sites have had concentrations below the national standard since the early 1990s.

Carbon monoxide air quality between 1980 and 2007, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 136 monitoring sites nationwide, with the average decreasing 76% from 1980 to 2007. Most of the sites have had concentrations below the national standard since the early 1990s.

How to Interpret the Graphs
View the chart data in Microsoft Excel (Download Excel Viewer)
View the chart data in HTML (New window opens)

Carbon monoxide air quality between 1990 and 2007, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 229 monitoring sites nationwide, with the average decreasing 67% from 1990 to 2007. Most of the sites have had concentrations below the national standard since the early 1990s.

How to Interpret the Graphs
View the chart data in Microsoft Excel (Download Excel Viewer)
View the chart data in HTML (New window opens)

Local Trends in CO Levels

Air quality trends can vary from one area to another. Local trends are available at individual monitoring locations with an adequate record of historical data.

Carbon Monoxide

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