Smoke from Canadian wildfires can travel hundreds or even thousands of kilometres, turning a distant fire into a serious air-quality emergency. That danger was starkly illustrated when wildfire smoke from Ontario moved into the United States and contributed to exceptionally poor air quality across parts of the Midwest.

Smoke from Canadian wildfires can travel hundreds or even thousands of kilometres, turning a distant fire into a serious air-quality emergency. That danger was starkly illustrated…

In Michigan, the Air Quality Index, as per Live Science, reached an extraordinary 616, significantly exceeding the EPA's hazardous classification.