Over the past 30 years, the federal Clean Air Act has drastically reduced air pollution across the country. As a result, Minnesota’s air quality is generally good, meeting all state and federal air quality standards. Yet even here, air pollution can reach unhealthy levels. When that happens, the MPCA issue air quality alerts. Keeping our air clean is everyone’s job.
The MPCA is responsible for understanding the condition of Minnesota's air, and there are many ways of looking at and measuring air quality. Each provides us a piece of the puzzle to understand how we are doing and where we need to focus in the future. The MPCA's biennial report on air quality, titled The Air We Breathe, summarizes Minnesota's air quality and our work to protect it.
Change in emissions in Minnesota since 1997
National ambient air quality standards
Under the Clean Air Act, the U.S. Environmental Protection Agency sets standards for six common air pollutants: ozone, fine particles, lead, nitrogen dioxide, carbon monoxide, and sulfur dioxide. The MPCA monitors air pollution across the state and compares the results to these national standards. In 2015, monitoring results in all areas of the state were better than the national standards.
The national standards are designed to protect human health and the environment. However, in recent years studies have shown that health effects occur even at levels below current standards, and disproportionately impact disadvantaged communities.
Trends in ozone and fine-particle pollution levels (2003-2016)
Health benchmarks for toxic air pollutants
“Air toxics” are a group of over 100 air pollutants that cause or may cause cancer or other serious health effects. Nationally, there are no enforceable regulatory standards for air toxics in the environment. Minnesota relies on guidelines called health benchmarks to evaluate the health risks from exposures to toxic pollutants in the air.
To protect the health of Minnesotans, MPCA works to keep all air toxics below health benchmarks. We monitor air toxics at nearly 20 locations in the state, with the majority of monitors located in the Twin Cities metro area. Each of these monitors measures over 70 air toxic pollutants. In 2015, the majority of monitoring sites measured air toxics concentrations below the health benchmarks. However, formaldehyde is above the health benchmark in the urban core of Minneapolis and St. Paul.
Air Quality Index
The MPCA’s Air Quality Index is a useful guide to air quality. The AQI tracks pollution levels in the air and tells us if the air is healthy to breathe. On most days, air quality is in the green or yellow zone -- healthy for all to breathe. But on several days each year pollutants such as ozone and fine particles can reach unhealthy levels, pushing readings into the orange zone -- unhealthy for sensitive groups. These are “bad air” days, when the MPCA issues air quality alerts. There were seven bad air days in 2016, mostly due to air pollution from regional wildfires.
Statewide AQI trends show improvements in air quality over time. Since 2003, the number of days with good air quality has nearly doubled. In 2005, air quality was considered good in all areas of the state on less than 25 percent of all days that year. In 2016, air quality was good in all areas of the state on more than 60 percent of all days.
Beginning in summer 2017, the MPCA will issue daily AQI forecasts and alerts (when needed) statewide. You can sign up to receive forecasts and alerts.
Number of good, moderate, and AQI alert days in Minnesota