Wisconsin's air quality trends

There is a statewide network of 31 ozone monitoring sites and 20 fine particle (PM2.5) monitoring sites to measure ambient air quality in Wisconsin. In addition, the DNR monitoring network measures sulfur dioxide, nitrogen oxide and carbon monoxide. The DNR monitoring network is operated under a federally approved network plan, submitted and reviewed annually to ensure appropriate monitoring in all locations required by federal regulations.

Under the Clean Air Act (CAA), the U.S. EPA sets National Ambient Air Quality Standards for pollutants. Data from Wisconsin’s monitoring network is validated and reported to the EPA to demonstrate how well air pollution controls and programs are working to improve air quality and meet the federal standards. In addition, using continuous monitoring data, DNR quickly informs the public when air pollution reaches unhealthy levels.

2017 Wisconsin Air Quality Trends Report

As part of its effort to meet CAA requirements, the DNR has released the 2017 Wisconsin Air Quality Trends Report (AM-553) [PDF]. The report shows that the overall air quality in Wisconsin continues to improve, building on a 20-year trend in the state.

We continue to work toward attainment in all counties and ensure compliance with all federal air requirements.

Previous reports

• December 2016 Wisconsin Air Quality Trends Report (AM-550) [PDF]
• December 2015 Wisconsin Air Quality Trends Report (AM-534) [PDF]
• April 2015 Wisconsin Air Quality Trends Report (AM-526) [PDF]
• 2014 Wisconsin Air Quality Trends Report (AM-523) [PDF]
• 2013 Wisconsin Air Quality Trends Report (AM-517) [PDF]

View county-by-county information

To view charts that show the air quality trends for ozone and fine particles (PM2.5) in each county, click on a shaded county in the map below (hover your mouse for the county name) or select a county from the drop-down list and then click the Submit button. Charts will appear below the map.

Note: In the charts, NAAQS stands for National Ambient Air Quality Standard [exit DNR].

Forest County