Thick smoke from nearly 950 active Canadian wildfires has swept across the U.S. border and placed more than 100 million Americans under air quality alerts, triggering dangerous PM2.5 particulate pollution levels across the Midwest, Great Lakes, and Northeast, according to the National Weather Service and reporting from the Canadian Interagency Forest Fire Centre. Officials in major cities including Chicago, Detroit, Washington D.C., Philadelphia, and New York have urged residents to limit outdoor activity and wear masks during peak pollution hours.
Air quality alerts as of Saturday, July 19, spanned portions of Minnesota, Michigan, Indiana, Ohio, West Virginia, Virginia, Maryland, Delaware, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire, and Maine, according to Forbes. At peak, CNN reported 18 states and the District of Columbia under alerts, with "very unhealthy hazardous" levels stretching from northeastern Minnesota to southeastern Virginia.
