CHICAGO— Smoke from wildfires burning in Canada continued to degrade air quality across broad areas of the United States on Saturday, prompting air quality alerts in parts of the Midwest, Great Lakes, Northeast and Mid-Atlantic as public health officials urged residents to limit prolonged outdoor activity.
The U.S. Environmental Protection Agency said it was monitoring air conditions through its AirNow network while coordinating with Canadian authorities and state, local and Tribal partners as smoke crossed the border. EPA Administrator Lee Zeldin said the agency was providing updated air quality information and public health guidance for affected communities.
The National Weather Service and state environmental agencies issued or maintained air quality alerts in several states, including Michigan and Ohio, where elevated concentrations of fine particulate matter from wildfire smoke were expected to persist through Saturday. Officials warned that air quality could range from "Unhealthy for Sensitive Groups" to "Very Unhealthy," with some locations briefly reaching hazardous levels.
The smoke originated primarily from large wildfires in Ontario, along with some fires in Minnesota, and spread southward under prevailing weather patterns. The haze reduced visibility in several metropolitan areas, including Chicago, Detroit and Washington, D.C., while health authorities advised older adults, children, pregnant women and people with heart or lung conditions to reduce outdoor exertion.
According to the EPA, wildfire smoke contains fine particulate pollution, known as PM2.5, that can penetrate deep into the lungs and aggravate respiratory and cardiovascular conditions. The agency recommends that residents in affected areas monitor local Air Quality Index forecasts, remain indoors when pollution reaches unhealthy levels, and use air filtration where available.
Forecasters said weather conditions, including scattered showers and shifting winds in some regions, could gradually improve air quality over the weekend, although smoke was expected to linger in parts of the eastern United States. AccuWeather forecast that conditions around the New York metropolitan area would improve before Sunday's FIFA World Cup final, though air quality was not expected to return fully to the "good" category.
Canadian authorities continue to battle hundreds of active wildfires, many in remote northern regions, with several communities under evacuation orders. U.S. officials said they would continue monitoring cross-border smoke transport and update public advisories as conditions evolve.
