More than 100 million Americans in the Midwest and Northeast were under air quality alerts across a dozen states on Thursday as smoke from Canadian wildfires drifted southward.
According to ranking site IQAir, as of Thursday morning Chicago had the worst air quality of any major city in the world.
“With no end in sight to the Canadian wildfires and west to northwesterly winds expected to persist from south central Canada into the north central to northeast U.S., poor air quality conditions are likely to continue,” warned the National Weather Service.
Canadian wildfire smoke would “reduce air quality over parts of the Upper/Middle Mississippi Valley, Great Lakes, Western Ohio Valley, Central Appalachians, Northeast, and Mid-Atlantic, prompting Air Quality Warnings over the area,” according to NWS.
Though the tracking site FlightAware reported that more than 1,000 flights within, in or out of the U.S. had been delayed as of Thursday morning, including more than 900 cancelations, the Federal Aviation Administration noted that flight disruptions on Thursday were likely to be caused by thunderstorms.
So far this year, some 3,030 Canadian fires have charred nearly 31,000 square miles.