Record-worst levels of wildfire smoke measured in several Minnesota communities

Records have been broken in several Minnesota communities, including parts of the Twin Cities, for the worst wildfire smoke measured, according to the Minnesota Pollution Control Agency.

State officials said they measure "fine particle concentrations" from the wildfire smoke. As of Friday at 8 a.m., there have been 82 hourly measurements collected between Wednesday and Friday greater than the previous hourly record of 476 micrograms per cubic meter, which was set last year.

In the northern Minnesota community of Virginia, a particle level of 1131.4 micrograms per cubic meter was measured on Thursday at 7 a.m., according to the state agency. An hour earlier in Ely, officials measured 797.5 micrograms per cubic meter. Areas in Duluth, Grand Portage and Fond du Lac had between 500 and 712 micrograms per cubic meter on Thursday night.

There were a record-level 382.5 micrograms per cubic meter in the metro city of St. Michael, Minnesota, on Wednesday at 7 p.m., the state agency said. On Pacific Street in Minneapolis, there were just over 364 micrograms per cubic meter at 10 p.m. the same day. 

An air quality alert is in effect until 11 a.m. Monday for the Arrowhead and 6 p.m. Friday for the rest of northern Minnesota, according to the National Weather Service. Levels are expected to reach hazardous levels through the weekend in the northeastern region. 

Sixteen wildfires were burning in the Superior National Forest on Friday afternoon, including three inside the Boundary Waters Canoe Area Wilderness, according to officials. Experts believe some of the blazes could continue to burn until snow arrives later this year.