‘Hazardous’ air-quality alert dropped in NW. Minnesota as cleaner air moves into state

Cleaner air has moved into northwestern Minnesota where air-quality alerts have been dropped, but the remainder of the state continues to be under advisories that are in effect until midday Wednesday.

A cold front combined with rain in parts of the state helped clean the air, and the trend will continue throughout Tuesday and into Wednesday as the worst air in four years moves out, said Ryan Lueck, an air-quality forecaster for the Minnesota Pollution Control Agency (MPCA).

The MPCA on Tuesday issued a rare hazardous warning for northwestern Minnesota due to thick concentrations of smoke from Canadian wildfires that filtered into the state.

The MPCA uses a color-coded scale when issuing alerts, with purple and maroon signaling when the air is the worst. On Tuesday, the agency issued a maroon warning for the northwest corner of the state and a purple warning for a large swath of northern and north-central Minnesota.

The agency has not issued a maroon warning since 2021, Lueck said.

“This is not common,” said Lueck, noting the air quality has reached such poor levels only “a handful of times” over the past decade. “It’s pretty rare.”

From 2021 to present day, the MPCA has issued 19 alerts with a maximum AQI category of red or unhealthy, and one with a maximum AQI category of purple or very unhealthy.

With Minnesota downwind from those fires, “it is only a matter of time before a change in the wind pattern brings more smoke into Minnesota,” Lueck said. “With more fires, there is a better chance we will be impacted by smoke.”

The long-range forecast calls for warmer than normal conditions across Canada during June, July and August, the Weather Network said. While there may be some storms on the northern side of a heat dome that could develop over the central United States and southern Canadian provinces, “the rain is not expected to be widespread enough to mitigate the threat of wildfires,” the station said.

In the short term, Minnesota looks to be nearly smoke free from Wednesday afternoon through Friday with no air-quality alerts in place, the MPCA said.

For the rest of Tuesday and into Wednesday morning, northeastern, central, south central, southeastern Minnesota and the Twin Cities area, a red alert for “unhealthy” air remained in effect.

At 7 a.m. Tuesday in Minneapolis, the air-quality index was at 263, or “very unhealthy,” according to the U.S. Environmental Protection Agency’s airnow.gov website. By noon, that number had dropped to 182.

The rain “has the potential to help clean the air, but is not expected to all-together eliminate poor air quality,” the MPCA said.

Air quality statewide is expected to improve on Wednesday, Lueck said. “Things will be better tomorrow.”

By Wednesday, only the northeastern counties will be under an orange advisory, with the remainder of the state experiencing cleaner air, the MPCA said.

The MPCA advises residents to take precautions: