Environmental Public Health Tracking: Air Quality Data

Air pollutants are substances in the air that should not be there or should be there in smaller amounts. These unwanted substances might be gases, liquids, or solids.

Many air pollutants result from human activities such as smoking, driving, manufacturing, and burning wood or coal. Pollution can also come from natural events such as wildfires.

You can be exposed to pollutants from the air by breathing in contaminated air or contaminated dust particles.

Air pollution is linked to lung and heart problems. It is also linked to asthma and can make health problems, such as emphysema, worse. The United States Environmental Protection Agency (EPA) provides a full list of the health effects of air pollution.

The first step is to know if you live in an area of the state that has high levels of pollution. Accessing our data will tell you how your community is doing over time. Additional information can be found on the Wisconsin DNR website.

If you are concerned about your personal risk, you can contact Wisconsin Tracking or your regional Department of Natural Resources office. You can also view daily current air quality information for Wisconsin or a map of current air quality for selected counties.

We focus on pollutants that are regulated by the United States government. The government regulates these pollutants through the Environmental Protection Agency (EPA). In Wisconsin, the Department of Natural Resources (DNR) provides standards for air quality. The data we share with you come from DNR monitoring stations around Wisconsin.

Data for two types of air pollution are available on this dashboard:

• Particulate matter under 2.5 microns (PM2.5)
• Ozone

The science that links air pollution to health and disease is complex. We do not suggest that you use our data to look for specific links between your health and your environment. This is because a number of factors – such as time and other exposures – can be important. Our data only provides a general level of pollution for different regions of Wisconsin over longer periods of time. For that reason, these data cannot be used to assess your personal risk. These data can tell you if the level of air pollution in your area of the state is changing over time.

• Wisconsin Department of Health Services - Air Quality Issues
• Wisconsin Department of Natural Resources
• US Agency for Toxic Substances and Disease Registry
• US Environmental Protection Agency
• AirNow
• US Wildfire Real-Time Data

Ozone

Number of days above standard

This measure is the annual number of days with maximum eight-hour average ozone concentration above the National Ambient Air Quality Standard. The measure includes both monitored and modeled data. The monitored data comes from the Wisconsin DNR. When data are available from multiple monitors for a given county and day, the highest eight-hour maximum (daily) ozone concentration among all the monitors is selected for purposes of creating daily county-level data. EPA provides modeled estimates of ozone using Downscaler (DS) model, which uses a statistical approach to fuse monitored data in areas where monitors exist, and relies on Community Multi-scale Air Quality (CMAQ) modeled output in areas without monitors. DS modeled estimates are available by census tract centroid; the geographic center of the census tract. Daily county-level modeled estimates are obtained by selecting the maximum value observed among all the census tracts within each county. County-level ozone measures are created using monitor data when available and using modeled estimates for days and locations without such data.

Particulate matter less than 2.5 micrometers (PM2.5)

Annual average concentration

This measure shows the average concentration of PM2.5 in a location over a year's span of time. The measure includes both monitored and modeled data, both coming from the EPA. When air quality data are available from multiple monitors for a given county and day, the highest 24-hour average (daily) PM2.5 concentration among all the monitors is selected for purposes of creating daily county-level data. EPA provides modeled estimates of PM2.5 using Downscaler (DS) model, which uses a statistical approach to fuse monitored data in areas where monitors exist, and relies on Community Multi-scale Air Quality (CMAQ) modeled output in areas without monitors. DS modeled estimates are available by census tract centroid the geographic center of the census tract. Daily county-level modeled estimates are obtained by selecting the maximum value observed among all the census tracts within each county. County-level PM2.5 measures are created using monitor data when available and using modeled estimates for days and locations without such data.

Percent of days above standard

This measure shows the percent of days of the year that the concentration of PM2.5 was higher than the EPA standard. The measure includes both monitored and modeled data. The monitored data comes from the EPA. When air quality data are available from multiple monitors for a given county and day, the highest 24-hour average (daily) PM2.5 concentration among all the monitors is selected for purposes of creating daily county-level data. EPA provides modeled estimates of PM2.5 using Downscaler (DS) model, which uses a statistical approach to fuse monitored data in areas where monitors exist, and relies on Community Multi-scale Air Quality (CMAQ) modeled output in areas without monitors. DS modeled estimates are available by census tract centroid the geographic center of the census tract. Daily county-level modeled estimates are obtained by selecting the maximum value observed among all the census tracts within each county. County-level PM2.5 measures are created using monitor data when available and using modeled estimates for days and locations without such data.