Canadian wildfire smoke continues to blanket large portions of the United States, affecting approximately 109 million people across the Midwest, mid-Atlantic, and Northeast. Cities such as Chicago and Detroit experienced hazardous air quality, with the Air Quality Index (AQI) reaching 361, according to the government website AirNow. Residents were advised to stay indoors and reduce activity levels.
Smoke Spreads to Major Cities
The smoke drifted into Baltimore and Washington DC overnight, creating very unhealthy air quality with AQI values of 281 and 247, respectively, as of 6 a.m. Eastern time. New York City, which has been shrouded in smoke since Tuesday, recorded an AQI of 184, classified as 'unhealthy.' Philadelphia and Cleveland reported 'very unhealthy' readings around 260. Other parts of Michigan, Minnesota, and Wisconsin also recorded AQI levels in the 'hazardous' range.
Global Comparisons and Health Advisories
The global air quality index showed pollution in five major North American cities at higher levels than Kinshasa or Nairobi in Africa. NASA's Fire Information for Resource Management System (FIRMS) indicates pockets of Canadian wildfires reaching deep into the Northwest Territories. In Michigan, the Department of Environment, Great Lakes, and Energy recommended closing windows, minimizing door openings, and using HVAC systems rated MERV-13 or higher. 'If you must be outdoors for short periods of time, an N95 or P100 respirator marked with NIOSH is recommended,' the advisory stated.
Forecast for Relief and Potential Worsening
Some cities in the Northeast and New England are expected to see relief from smoky skies on Friday as stronger winds from Quebec—outside the wildfire zone in western Ontario—blow the smoke away. However, an approaching storm system from the west, bringing severe thunderstorms, could interact with the smoke and worsen conditions by dragging smoky air from higher altitudes down to the ground. Forecasters say air quality is likely to improve after the storm passes late on Saturday, in time for the World Cup final kick-off at 3 p.m. Sunday in East Rutherford, New Jersey.
Scale of Canadian Wildfires
Canada's largest fire, near Ontario's remote Wabakimi Provincial Park, has spread across 787,802 acres (318,812 hectares), according to the Canadian Interagency Forest Fire Centre. It is among 194 out-of-control and large fires burning as of Thursday. Mark Parrington, senior scientist at the Copernicus Atmosphere Monitoring Service, stated: 'There has been a clear intensification in wildfire activity for Canada over the past few weeks. Smoke from major fires—particularly in Ontario—[is] already having severe air quality impacts across cities in the Great Lakes region and the north-eastern United States.' He added that forecasts show smoke continuing eastward across the North Atlantic, potentially reaching Europe.
Broader Impact and Other Fires
Nearly 6 million acres are estimated to have burned, less than a quarter of the land consumed by blazes when Canadian wildfire smoke last blanketed the US in 2023. Fires in northern Minnesota have burned more than 63,000 acres. In the western US, wildfires in Oregon, Washington, and Idaho have also been reported. Forecaster Colin McCarthy noted on Thursday evening: 'The wildfire situation across North America just got worse. Tens of thousands of lightning strikes across the Pacific Northwest [have] ignited dozens of new wildfires across Oregon and Washington.'
