Canadian Wildfires Continue to Impact US Air Quality.

Smoke from dozens of wildfires in Ontario, Canada, has caused air quality alerts across the Upper Midwest, including Minnesota and Wisconsin. The smoke has caused levels of "unhealthy" or "very unhealthy" air quality, with the worst conditions expected on Wednesday night. The air quality alert in Minnesota has been extended through Friday morning, while the alert in Wisconsin is in effect until noon local time Thursday. Smoke from the fires has also been detected over parts of Kentucky, Illinois, Indiana, Michigan, Ohio, and North Dakota. Scientists warn that such events are more likely to continue as the planet warms, creating the ideal environment for more severe and frequent wildfires.