The Minnesota Pollution Control Agency's air quality alert covering the Twin Cities metro started Thursday at 3 p.m. and runs until 11 a.m. Friday, with smoke from large wildfires in the Arrowhead region pushing south into central and southern Minnesota. Thursday marked the first time on record the Twin Cities metro has hit the agency's "hazardous" air quality designation, and Minneapolis was at times the most polluted major city on Earth, according to the Swiss air monitoring firm IQAir.
The pollution control agency's alert splits the state into color-coded zones. East central and northeast Minnesota hit the maroon, or hazardous, category, where everyone is advised to avoid outdoor activity entirely and stay inside. The Twin Cities metro, along with central, west central, southeast and north central Minnesota, falls into the purple and red bands, meaning residents should avoid prolonged or heavy exertion outdoors and sensitive groups — including kids, people with asthma and pregnant people — should limit outdoor time altogether.
The smoke is landing on top of an extreme heat warning for the metro that runs until 9 p.m. Friday, with highs near 95 degrees and heat index values pushing 100.
Staying inside doesn't fully solve the problem, either. Smoke seeps indoors, so Dr. Sarah Lacher of the University of Minnesota Medical School recommends running an air purifier and, if possible, tracking indoor air quality with a personal AQI monitor rather than assuming closed windows are enough. Anyone checking conditions before heading outside can look up real-time readings for their area on AirNow.gov, which the pollution control agency and health officials point to as the go-to source for current AQI by location.
The smoke is tied to a brutal wildfire season north of the border: as of Thursday, Canada was reporting 860 active fires burning more than 2.4 million hectares, with 107 of those still out of control. Closer to home, the U.S. Forest Service has kept the Boundary Waters Canoe Area Wilderness closed to protect firefighters and visitors from the fires burning in the Arrowhead. Campus community members with respiratory conditions should keep checking AQI readings before spending extended time outside.