St. Paul had the worst air quality in the United States on Wednesday as smoke from massive Canadian wildfires drifted across Minnesota a week after similar smoke blanketed the northeastern U.S.

The smoke was “near the worst” on record for the Twin Cities, the Star-Tribune reported, citing Nick Witcraft, an air-quality meteorologist with the Minnesota Pollution Control Agency.

Air quality hit “red” on the U.S. government’s color-coded index, meaning it was unhealthy for everyone. The air was particularly dangerous for children, older people, and those with asthma and conditions like diabetes and heart disease.

Despite the air, Karen Berg-Moberg decided to go on a bike ride at Como Lake in St. Paul with a friend. She was ready to cut their trip short if needed but didn’t think the smoke would slow them down.

“I can smell it. It’s kind of nasty,” she said. “We debated it, but thought, ‘What the heck?’ ”

St. Paul had an air quality index, or AQI, reading of 256 at 6 p.m. Wednesday, according to AirNow.gov, a website published by U.S. government agencies. The index runs from zero to 500. The higher the number, the worse the air quality.

In July 2021, the index reached 182 in the Twin Cities, after wildfire smoke drifted down from Canada.

Minneapolis public parks officials canceled events for music and movies in the park and outdoor activities on Wednesday. St. Paul canceled all youth and adult athletics.

Last week, massive fires burning up stretches of Canadian forests blanketed the northeastern United States, turning the air a yellowish gray and prompting warnings for people to stay inside and keep windows closed.

The small particles in wildfire smoke can irritate the eyes, nose and throat, and affect the heart and lungs, making breathing harder. Health officials say it’s important to limit outdoor activities as much as possible to avoid breathing in these particles.