Tens of millions of Americans are under air quality alerts Wednesday as a smoky haze from the ongoing Canadian wildfires envelops the skies of large portions of the Midwest and some areas of the East Coast, according to CNN.

The National Weather Service (NWS) has issued air quality alerts for all or parts of Iowa, Wisconsin, Michigan, Ohio, Pennsylvania, New Jersey, Pennsylvania, Maryland, New York, Indiana, Illinois, Minnesota, Virginia, North Carolina, Kentucky and Washington, D.C., as smoke from the ongoing Canadian wildfires hangs over large portions of the U.S. Air quality alerts issued Wednesday cover at least 80 million Americans, according to CNN.

The air quality alerts are back in effect over large swaths of the country, weeks after the NWS issued air quality alerts earlier in June which included at least 115 million people in their scope. This summer’s fires have already burned at least 19 million acres of land across Canada as of Tuesday, according to CNN.