Air quality alert expanded as pollution reaches record levels

Smoke from Canadian wildfires drifting into Minnesota degraded air quality across the state Wednesday, with pollution reaching record levels unhealthy for all groups, not just those most at risk.

The wildfire smoke prompted the Minnesota Pollution Control Agency (MPCA) to expand an air quality alert for northern Minnesota to include central Minnesota, effective until 6 a.m. Friday. A separate alert was in effect due to high levels of ozone for southeast Minnesota until 8 p.m. Wednesday.

By Wednesday afternoon, air quality levels in parts of the state had reached the red level, which is unhealthy for everyone and particularly dangerous for people in sensitive groups — those with asthma, chronic obstructive pulmonary disease (COPD), diabetes or heart disease, as well as children and seniors.

Nick Witcraft, an air quality meteorologist with the MPCA, said that Wednesday's smoke was the worst on record for the Twin Cities. While 2021 had worse air quality in parts of northern Minnesota, Witcraft said this year's bout of poor air quality is more widespread and worse in the Twin Cities.

"I think it's fair to say probably this one now is the worst episode in the Twin Cities," he said.

It was a challenge to compare the hourly readings showing up on monitoring websites, he said, because historical Air Quality Index (AQI) data is averaged over a 24-hour period.

But at 6 p.m. Wednesday, St. Paul had the worst air quality in the United States, with a score of 256, according to AirNow.gov, the official U.S. AQI site. While the AQI index goes up to 500, readings above 200 are considered sufficiently hazardous that outdoor activities are discouraged. St. Cloud's AQI was 202. In comparison, the agency said the air-quality score at the U.S. embassy in Beijing was 86 on Wednesday.

When wildfire smoke traveled south from Canada in July 2021, one daylong average for the Twin Cities reached 182 AQI, solidly in the red category, Witcraft said. One monitor just south of downtown reached an hourly reading of 215 AQI, or the purple, "very unhealthy" category. But Witcraft said this smoke coverage may not be considered as bad as the 2021 event, because the haze is expected to clear much more quickly, by Thursday at midday.

Despite the hazy skies and acrid air covering the Twin Cities, some still ventured outdoors.

Karen Berg-Moberg decided to go on a bike ride at Como Lake in St. Paul with a friend, saying she didn't think the smoke would slow her down — though they were ready to go a shorter distance if necessary.

"I can smell it. It's kind of nasty," she said. "We debated it, but thought, 'What the heck?' "

Devin Schmidt and Ellie Richardson took a walk around the lake, and said their breathing was fine.

"Mentally, it's discouraging," Richardson said. "It's just sad."

Joe Cabrera and Jodie Ferri were walking on the footpath around the lake. Though Cabrera said the smoke didn't bother him, Ferri said she's had some throat irritation for the past couple of days and lost her voice.

"I don't have any particular explanation for it," she said, but wondered if it was related to the air quality.

Fine particle pollution from wildfire smoke can irritate the eyes, nose and throat, and cause coughing, chest tightness, shortness of breath, dizziness or fatigue.

Ozone is produced on hot, sunny days by a chemical reaction between volatile organic compounds and oxides of nitrogen. High levels can aggravate lung diseases such as asthma, emphysema and COPD, according to the MPCA.

People in sensitive groups are encouraged to reduce outdoor physical activity and avoid prolonged time outdoors until air quality improves, the MPCA said. The American Lung Association encouraged people to protect indoor air quality, too, by keeping doors, windows and fireplace dampers shut and circulating clean air using the recirculation setting on air conditioners.

Reducing outdoor burning and use of gas-powered machinery and cutting down on vehicle trips during the afternoon and early evening when ozone levels are highest can help reduce air pollution, the National Weather Service said.

Among cancellations Wednesday because of the air quality were the Minneapolis Park and Recreation Board's outdoor programming, including Music and Movies in the Park events, athletic field rentals and events, and outdoor activities for youth and adults.

St. Paul Parks and Recreation canceled all youth and adult athletics Wednesday. Makeup games will be scheduled for the end of the season, according to the department's Twitter post.

The Minnesota Aurora women's soccer team cancelled its outdoor game at TCO Stadium against the Green Bay Glory due to the poor air quality. Instead, it was played at a private indoor setting and was closed to all fans, according to the club's Twitter post. Those who bought tickets will get a full refund within the next three to five business days, the post said.

Canterbury Park also called off its horse racing early on Wednesday.

Staff writer Louis Krauss contributed to this report.