Air quality in Minnesota

Air quality affects heart & lung health

Air pollution is associated with a variety of harmful respiratory and cardiovascular effects, including asthma, pneumonia, bronchitis, and heart attacks. The severity of these effects varies depending on the type of the pollutant, level of exposure, and individual susceptibility.

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The air quality indicators developed for this web site are based on measurements of ground-level ozone and fine particles (also known as PM2.5) in outdoor air. High levels of ozone and PM2.5 are the primary cause of poor air quality episodes in much of the US, including Minnesota.

Children and adults who participate in heavy or extended physical activity, and people with respiratory and cardiovascular diseases are especially vulnerable to the harmful effects of air pollution.

PM2.5 and ozone are major causes of poor air quality


PM2.5 is a mixture of small particles and liquid droplets smaller than 2.5 microns in diameter. PM2.5 is released when coal, gasoline, diesel fuels, wood and other fuels are burned. PM2.5 is also created by chemical reactions between other pollutants in the air.

Additionally, PM2.5 is released by tobacco smoke and home heating sources, such as wood burning stoves and fireplaces. Depending on these activities and home environment characteristics (e.g. air ventilation), PM2.5 indoor exposures may be higher than outdoors.

PM2.5 can be inhaled deep into the lungs and even reach the bloodstream. The particles can accumulate in the respiratory system and cause serious health effects. Scientific studies, for example, have linked particle pollution to respiratory and cardiovascular diseases, including heart attacks, asthma, bronchitis, and other respiratory illnesses including potentially lung cancer.


Ozone is a colorless gas composed of three atoms of oxygen. In the upper atmosphere this gas helps protect the earth from the sun's damaging ultraviolet rays. At ground level, however, ozone can be harmful to human health and the environment.

Ground-level ozone is not emitted directly into the air but is created through a series of reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) mixing in the presence of heat and sunlight. Because of the role of heat and sunlight in the formation of ozone, ozone is generally not a concern in Minnesota during the winter months. On hot, sunny summer days, however, ozone concentrations can rise to unhealthy levels.

Sources of pollutants that form ozone include gasoline and diesel vehicles, construction equipment, and electric utilities. Additionally, paints, solvents, and glues/adhesives contain chemicals that may form ozone.

Ozone is also a known lung irritant, associated with a variety of respiratory effects, including chest pain, asthma, bronchitis, and emphysema.

Reduce your exposure to air pollution

  • Be aware of Minnesota Pollution Control Agency (MPCA) Air Quality Index (AQI) forecasts and alerts in your area. Sign up for air quality alerts.
  • Avoid exposure to tobacco smoke, wood smoke, vehicle exhaust, and other sources of PM2.5 when possible.
  • Avoid prolonged outdoor physical activity on air quality advisory or alert days and near high-traffic areas.
  • On days with high ozone concentrations, plan physical activity for the morning hours when ozone concentrations are lowest or move activities to an air-conditioned, indoor area.
  • Take action to reduce PM2.5 and ozone levels in your community.
    • Fuel you car early in the morning or in the evening when temperatures are cooler.
    • Consider the use of electric or manual lawn mowers and other yard tools.

What is being done about PM2.5 and ozone?

  • Minnesota’s most vulnerable populations – seniors, the poor, people without health insurance and people with chronic health conditions are being hurt by poor air quality. Inequities like income, racial discrimination, education, and housing are major contributors to how health is affected by air pollution. Learn more in two recent reports: Life and Breath: Metro (updated 2022) and Life and Breath: Greater Minnesota (2022).
  • MPCA also operates a statewide air monitoring network and reports its results to EPA to ensure air quality in Minnesota meets the NAAQS. Explore in-depth air monitoring data for multiple pollutants and locations.
  • MPCA reports the Air Quality Index (AQI), a real-time measure of air quality conditions across the state. Individuals can use the AQI to plan their activities during periods of poor air quality to minimize exposure.
  • The U.S. Environmental Protection Agency (EPA) sets National Ambient Air Quality Standards (NAAQS) for six pollutants considered harmful to public health and the environment. These pollutants include ozone, PM2.5, lead, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The EPA is required to review the scientific basis of the NAAQS every five years and revise them as necessary to ensure adequate public health protection. States are required to meet these regulatory standards.
  • The MDH Climate & Health Program works with partners to increase awareness of the public health impacts of poor air quality and conducts research to support health and climate solutions.
  • The Minnesota Pollution Control Agency (MPCA) is responsible for implementation and enforcement of the NAAQS in Minnesota. To accomplish this, MPCA requires businesses to apply for air pollution permits. Permit applicants must demonstrate that pollution emissions will not cause air quality to violate the national standards.
  • Centers for Disease Control and Prevention (CDC) has comprehensive information about how to protect yourself from wildfire smoke.

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Last updated May 2020. Updates are made when data become available.