As we approach summer, the Minnesota Pollution Control Agency (MPCA) has released their air quality forecast for the season. Air quality is predicted to be better than the 2023 level, but MPCA meteorologists are expecting more alerts than normal. 

The forecast for another summer of increased air quality alerts in Minnesota is due to anticipated high temperatures and a more-than-average number of wildfires. Parts of Canada and Minnesota show persistent drought in modeling from MPCA and its federal partners. This alongside other factors could contribute to large wildfires that would impact air quality.

Minnesota had a record 21 Air Quality Alerts that spanned 52 calendar days in 2023. Of those, 16 were because of wildfire smoke increasing the amount of fine particles in the air. Nine alert days reached the red Air Quality Index (AQI) category, which is dangerous for everyone.

“Wildfires in Canada and other states have a significant impact on Minnesota’s air quality, and last year was profound,” said MPCA lead meteorologist Matt Taraldsen. “Our meteorologists are closely monitoring air quality around the state, and we are committed to providing accurate information promptly so that everyone can stay informed about changing conditions.”

MPCA experts added that though not projected to reach 2023 levels, wildfire smoke this summer will impact Minnesotans’ quality of life and outdoor plans as we see more weather patterns shift in the state. Wildfires are becoming larger and more frequent in the summer in both the U.S. and Canada. Fires start and spread easily due to warmer temperatures and persistent drought conditions, and the smoke can travel thousands of miles. 

Recent rain has improved drought conditions with none of Minnesota currently in severe drought. 11% of the state is in moderate drought, and 28% is abnormally dry. Long-term forecasts call for average rainfall this summer and above-average temperatures. Parts of Minnesota and much of Canada are expected to continue to experience some degree of drought throughout the summer. 

According to the MCPA, Minnesotans can expect to see more wildfire smoke than average. There is an average of 5-7 alerts per year, and forecasters predict 2024 will have greater than seven alerts. 

In addition to wildfire smoke impacting air quality, ozone can also cause alerts to be issued. Slightly above-normal temperatures can elevate surface ozone, particularly in early summer. Forecasts predict this year to have 2-4 days with ozone-related Air Quality Alerts, which is slightly above-average by one day. The suburban Twin Cities area and Rochester metro areas are most vulnerable to ozone impacts, but persistent wildfire smoke could aid in the generation of surface-based ozone. This interaction was observed during the 2023 season.

Those who monitor the Air Quality Index closely may notice more days in the Yellow, or moderate, category as the lower threshold has been decreased.

“There’s been new research out there that air quality pollution that’s not quite up to that orange level and healthy for sensitive groups can still impact people who are very sensitive to air quality. So people who have COPD, emphysema, and underlying health conditions like that,” explained Taraldsen. “That will mean that we’ll have a lot more of those yellow or moderate days, especially in the Twin Cities, but even probably in the Duluth area as well.”

An Orange Air Quality Index is needed for an alert to be issued, and that category is being kept the same. The highest category, however, will have a lower threshold.

“Last year, we’d not have any Purple Air Quality Alerts, but they would be purple now this year with those new changes. Those changes stemmed from new research that’s come out mainly for the 2021 wildfire season across the US and Canada, but indicating that there’s a higher impact of air quality pollution on the human body at a lower level than what we thought and at a faster interval than 24 hours,” said Taraldsen. “So the new changes basically just allow us to kind of hone in and give specific timing of when we think the worst air quality impacts will be.”