While an air quality alert continues for parts of the Midwest due to smoke from Canadian wildfires, northeastern Illinois was expected to shift away from air quality issues that persisted over the last week,

However, Lake, Porter, Newton and Jasper counties in Indiana will be under another air quality alert all day Tuesday. The Chicago area had been under air quality alerts for much of the last week, due to smoke from Canadian wildfires. At one point last week, Chicago had the worst air quality in the world.

Air quality will deteriorate across 12 states through Saturday, mainly in the Upper Midwest, as wildfire smoke pours into the US from northwestern Canada brought by the cold front that is ushering in a brief summer cooldown.