Wildfire smoke is back – fires burning across Canada are already triggering US air quality alerts in the Midwest and Plains

Pittsburgh Pirates center fielder Andrew McCutchen wore a face mask to protect against smoke in the air during a Pirates-Padres game on June 29, 2023, in Pittsburgh. Nick Cammett/Diamond Images via Getty Images by Charles O. Stanier, University of Iowa; Gregory Carmichael, University of Iowa, and Peter S. Thorne, University of Iowa Dozens of wildfires are burning across Canada in May 2024 and sending unhealthy smoke blowing into the northern U.S. again. At the same time, the southeastern U.S. is getting smoke from Mexico, where drought conditions have been fueling fires. Last year, Canada’s record 2023 wildfire season introduced millions of Americans across the Midwest and northeastern states to the health hazards of wildfire smoke, with air quality alerts that reached levels never seen there before. Professional baseball games were postponed and the skies in New York City turned orange with haze, at times exposing millions of people to the worst air quality in the world. In some regions, the smoke hung on for days. The pressing question on many people’s minds: “Is this the new normal?” From our perspective as air quality scientists, we think the answer is likely “yes.” Global warming means more fires Hotter, drier conditions, coupled...