In Minnesota’s Twin Cities, the AQI (air quality index) was the worst it had been since the Minnesota Pollution Control Agency began keeping records in 1980. On Wednesday, the area had the worst air quality in the country, CBS Minnesota reported.

Much of the United States has dealt with AQI issues in recent weeks as smoke from Canadian wildfires swirls through the atmosphere.

Earlier June, parts of the East Coast, including New York City, saw sky-high AQI readings in the 400s.

Numbers that high are considered hazardous, and people were advised to stay indoors as much as possible and wear high-quality masks for any necessary outdoor activity.

It is possible that the East Coast will have air quality issues again in the coming days, the Weather Channel reported on Thursday.

“What’s going to happen over the next few days is we’re going to start to see a shift in the pattern that’s going to bring the smoke a little bit farther toward the east,” said Weather Channel meteorologist Ari Sarsalari.

The smoke will travel over the Great Lakes, he said, before reaching the coast, especially in the North Atlantic region, likely on Friday into Saturday.

It’s not clear how severe the impact will be, he said, but there will likely be noticeable air quality issues, especially for people who have respiratory problems.

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