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All About Outdoor Air Quality
All About Outdoor Air Quality
By Mari Friel, Minnesota Pollution Control Agency Environmental Education and Outreach Intern, Summer 2025
By Mari Friel, Minnesota Pollution Control Agency Environmental Education and Outreach Intern, Summer 2025
Published January, 2026
Published January, 2026
Air quality alerts are becoming increasingly common in Minnesota. In this article, you’ll learn what the Air Quality Index is, how to track outdoor air quality, what to do to protect student and staff health during air quality alerts, and ideas for Green Team projects and events.
Image: Air Quality Index chart
Source: Understanding the air quality index (AQI) | Minnesota Pollution Control Agency
What is the Air Quality Index?
What is the Air Quality Index?
The Air Quality Index (AQI) was developed by the U.S. Environmental Protection Agency (EPA) to provide a simple, uniform way to report daily air quality conditions and enhance human health by helping residents avoid risks from air pollution. Minnesota AQI numbers are determined by hourly measurements of five pollutants. The pollutant with the highest AQI value determines the overall AQI for that hour. When the forecasted AQI values are expected to be over 100, an air quality alert is issued. AQI forecasts depend on temperatures, precipitation, wind, and cloud cover. Weather affects pollution creation and transport to and from areas.
The AQI has six levels of concern, each with an index value range and color. When the AQI is above 100 the air is unhealthy for sensitive groups and people should consider reducing the duration and intensity of outside activities and take breaks. Download the EPA AirNow app on your phone to check the current air quality and receive MPCA alerts.
Image: Air pollution sources in Minnesota.
Transportation and permitted facilities create the largest share of air pollution risk across the state, though residents of Greater Minnesota are more likely to see air pollution risk from burning wood or agricultural sources than those in the metro area.
Source: The Air We Breathe report | Minnesota Pollution Control Agency
What are the major sources of air pollution that can lead to health effects in Minnesota?
What are the major sources of air pollution that can lead to health effects in Minnesota?
Air pollution comes from many sources. Local sources of air pollution are transportation, permitted facilities, and burning wood for heat or recreation. Distant sources, such as smoke from fires in Canada or the western U.S., also impact our air quality.
There are three main conditions that cause poor air quality in Minnesota. The first is wildfire smoke moving into and around the state, which is becoming more frequent during the summer months. The second is high concentration of ground level ozone, which is most common during the warmest months of the year. And lastly temperature inversions which are most common in winter months and occur when a layer of warm air traps cooler air near the Earth’s surface, causing stagnant air and air pollution to become more concentrated.
Tips for schools
Tips for schools
Minnesota GreenStep Schools describes best practice actions for outdoor air quality under Best Practice 2.2. The following resources for schools will help school leaders stay aware of air quality, act on reducing air pollution, and protect and improve the health of students and staff.
Make a plan for bad air days. School administrators can check the AQI daily and email students, families, and staff if there is an air quality alert or if they should take precautions to protect their health. Outdoor air quality guidance for schools and child care, from the Minnesota Department of Health, is helpful for schools to use when determining whether events or sports practices should be modified or canceled.
Train sport coaches. Encourage Athletes and Asthma: The Community Coach's Role for afterschool sport coaches. This 35-minute online, free training from the Minnesota Department of Health prepares coaches to help players of all ages who have asthma, play to their full potential, developed with expertise by the MDH Asthma Program.
Promote active transportation. Encourage walking and biking to school and provide information on public transportation.
Transition to electric mowers, snowblowers, and other grounds maintenance equipment to reduce on-site pollution. Recommend or require grounds staff to postpone gas-powered maintenance during air quality alerts.
Transition to electric school buses to reduce children’s exposure to diesel pollution.
Plant trees, native plants, and low allergenic plants around the school grounds to clean the air, create shade, and support pollinators.
Purchase or apply for a grant for air quality sensors to be put at the school. PurpleAir is a popular real-time air sensor that can be bought online and already has a large network across the country. Check out the Minneapolis PurpleAir Sensor program and the MPCA’s information on air quality sensors.
Ideas for Green Teams!
Ideas for Green Teams!
Student Green Teams or Eco Clubs play an important role in sharing information about environmental issues and creating change at schools. Listed below are some ideas for events and initiatives that students can try at their schools.
Organize and put on an air quality awareness week during the school year. This week is usually one of the first weeks in May. Check the EPA website for this year’s dates. Encourage students and staff to bike, walk, or take public transportation to school to reduce air pollution. Plan some events, have prizes, and teach people about air quality!
Join the Air Quality Flag Program. The Air Quality Flag Program uses brightly colored flags based on the U.S. EPA’s Air Quality Index to notify people and their communities about outdoor air quality conditions. Organizations raise a flag each day that corresponds to their local air quality forecast. Follow the steps on the EPA website to begin. Ask school administrators for help with ordering the flags. Create a plan for flying the day’s air quality flag and educating your school and the community about the program.
Create posters about fine particle pollution and ground-level ozone. Research fine particles and ground-level ozone, the sources, health effects and symptoms, and what we can do to protect our health and reduce air pollution. Make sure to add visuals to the posters so staff and students are more likely to stop to read them and learn more about these air pollutants.
Plan a Tree planting day where students can plant trees near the school and learn about the benefits trees have for absorbing air pollutants, filtering particulate matter, and reducing temperatures. Contact local community organizations or conservation groups that would be willing to partner with the school to help make this event happen or consider volunteering with one of these groups for a tree planting event. Look on the DNR website for resources on planting and caring for trees and information about Arbor Day and Arbor Month.
Mari Friel
About the Author
About the Author
Hello, my name is Mari Friel, this summer I am interning at the Minnesota Pollution Control Agency (MPCA) in the Environmental Education and Outreach unit. I am a part of the Increasing Diversity in Environmental Careers (IDEC) program through the Conservation Corps of MN and IA, which is a program that supports underrepresented undergraduate college students studying the environment. I am a Junior at St. Olaf College studying environmental studies and Japanese.
As an intern, I have worked on creating presentations and activities about air quality that staff at the MPCA can use at schools or outreach events. I also gained outreach experience guiding visitors through the We Are Water MN exhibit while it was in downtown Minneapolis and assisted with setup and volunteering at the Eco Experience building at the Minnesota State Fair.
Informing the public about air quality is very relevant right now as we are experiencing more poor air quality days due to wildfire smoke. I hope this article can help!
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