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Environmental Public Health Tracking: Air Quality Data

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Wisconsin Tracking provides information about air quality in Wisconsin.

Air pollution means something is in the air that should not be there or should be there in smaller amounts.

We host data on air quality measures that have standard levels defined by the federal government. These measures include particulate matter under 2.5 microns (PM2.5) and ozone.

Wisconsin Tracking gets information about these air pollution measures from air monitoring stations all over Wisconsin.

Access the air quality data

Wildfire smoke will likely affect air quality in Wisconsin

Smoke from wildfires can affect our air quality, even when the fire isn't in our state. Fires from nearby, or as far away as Canada, can affect anyone, but especially people with asthma, COPD, and heart disease. The latest real-time forecast data on the affected areas is displayed on this map:

To interact with a larger-scale map of the effects of today's wildfires, visit the National Environmental Public Health Tracking Network.

Wildfire smoke can cause or exacerbate health problems, especially for people with asthma, COPD, or heart disease. To better understand the health impacts of wildfire smoke and learn how to stay safe, visit the CDC's (Centers for Disease Control and Prevention) wildfire smoke page.

For more information about types of air pollution, visit the air quality issues page.

Interested in environmental health data?

Join the environmental health listserv by sending an email to DHS Environmental Public Health Tracking with the subject line "Join envhealth listserv."

Frequently asked questions

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 particulate matter and ozone.

The first step is to know if you live in an area of the state that has high levels of pollution. Accessing the Wisconsin Tracking air pollution 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.

Wisconsin Tracking focuses 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 on our portal are from DNR monitoring stations around Wisconsin.

Data for two types of air pollution are available on the data portal:

  • 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 Wisconsin Tracking 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. The data on our public data portal only provide a general level of pollution for different regions of Wisconsin over longer periods of time. As such, 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.

Air quality data details

Read frequently asked questions about the air quality data

Ozone

Annual 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 U.S. Environmental Protection Agency (EPA) Air Quality System (AQS). When AQS 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.

Annual person-days above standard

This measure is the annual number of person-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 U.S. Environmental Protection Agency (EPA) Air Quality System (AQS). When AQS 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 person-days above standard

This measure is the annual number of person-days with particulate matter less than 2.5 micrometers (PM2.5) levels above the National Ambient Air Quality Standard. The measure includes both monitored and modeled data. The monitored data comes from the U.S. Environmental Protection Agency (EPA) Air Quality System (AQS). When AQS 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.

Average annual concentration (μ/m3)

This measure is the annual average ambient concentration of particulate matter less than 2.5 micrometers (PM2.5) in micrograms per cubic meter (based on seasonal averages and daily measurements). The measure includes both monitored and modeled data. The monitored data comes from the U.S. Environmental Protection Agency's (EPA) Air Quality System (AQS). When AQS 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.

Explore definitions and explanations of terminology found on the portal, like age-adjusted rate and confidence intervals.

Last revised October 6, 2023