Air Trends

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 1980-2008 and from 1990-2008 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/airquality/carbonmonoxide.

Carbon monoxide air quality between 1980 and 2010, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 104 monitoring sites nationwide, with the average decreasing 82% from 1980 to 2010. Most of the sites have had concentrations below the national standard since the early 1990s.

Carbon monoxide air quality between 1980 and 2010, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 104 monitoring sites nationwide, with the average decreasing 82% from 1980 to 2010. 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 2010, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 170 monitoring sites nationwide, with the average decreasing 73% from 1990 to 2010. 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 2000 and 2010, based on the annual second maximum 8-hour average. Chart shows a range of concentrations in 265 monitoring sites nationwide, with the average decreasing 54% from 2000 to 2010. 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 can be viewed at individual monitoring locations in the map below or in this KML file (KML, 352 KB) using Google Earth or another KML browser.

Carbon monoxide monitors that meet mimimum trends completeness criteria

Carbon monoxide monitors that have some data during the trend period but do not meet the mimimum trends completeness criteria for 1990-2010

Carbon Monoxide

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