Is Ground-Level Ozone Really a Problem In Wisconsin?
Environmental Protection Agency designated the counties along the Lake Michigan shoreline as not attaining the ozone standard. Significant efforts to control ozone have paid off for southeastern Wisconsin. Since 1992, the air quality is good in 70 - 80% of the days monitored and we are experiencing fewer days when the Air Quality Index (AQI) is unhealthy. When we look at the historic annual maximums, we see a steady decline in the highest AQI. Monitoring data in the Madison and Janesville-Beloit areas show a steady decline in the highest annual AQIs while it’s more difficult to detect a trend in Green Bay, Wausau, northern Wisconsin and western Wisconsin near Minneapolis. At the more inland locations between April and October the air quality varies from year to year but is good in roughly 90% of the monitoring season.
Substantial progress has been made in improving air quality. Continued control programs and voluntary efforts such as the Partners for Clean Air in the Milwaukee area and the Cleaner Air Faster effort stretching from Green Bay down to Beloit are needed to further protect and improve air quality. For more information go to DNR Air Website at Historical Ozone Data Graphs by Monitoring Site.