Canadian wildfire smoke triggers US air quality alerts

Daily Mail​

15-07-2025

Officials have issued an air quality alert for around 10 million Americans, telling them to minimize outdoor activities and shut all windows on Tuesday. A National Weather Service (NWS) map shows parts of Minnesota, Michigan, Illinois, New York, Vermont, Indiana and Maine are under advisories until midnight as wildfire smoke from Canada drifts into the US. The alerts stem from elevated levels of ground-level ozone and fine particulates, prompting precautionary measures.
In Upstate New York, Vermont, and Maine, residents are advised to limit strenuous outdoor physical activity to mitigate health risks, according to the New York State Department of Health. The NWS has specifically warned residents in northeast Minnesota, eastern Michigan, northeast Illinois and northwest Indiana to keep windows closed overnight to prevent smoke infiltration. Current advisories indicate that ozone levels are not expected to reach 'dangerous' levels (AQI 201 or higher) in any affected region.
The highest ozone-related concern is in Michigan's St. Clair to Monroe counties and New York's Niagara to Southern Erie counties, where levels are in the 'Unhealthy for Sensitive Groups' range (AQI 101-150). Other regions are primarily under fine particulate alerts, with no ozone warnings suggesting dangerous conditions, which are small enough to penetrate deep into the lungs and affect the heart. Last week, six US lawmakers wrote to Canada's ambassador, complaining that wildfire smoke drifting south was making it hard for Americans to enjoy the summer.
In response, the premier of Manitoba accused them of 'trivializing' a deadly crisis. The fires continue to spread across thousands of acres. May and June were especially destructive in western Canada, where about 30,000 people were forced to evacuate in Saskatchewan and Manitoba, prompting states of emergency in both provinces.
The Air Quality Index (AQI) is expected to exceed 101, signaling potential health risks. Separately, an advisory for fine particulates is active until midnight in Lewis, Livingston, Ontario, and Allegany, including cities such as Lowville, Geneseo, Canandaigua, and Wellsville. Similar alerts for fine particulates, with AQI levels predicted above 100, are in effect from 10 AM to midnight in regions including Northern St. Lawrence, Franklin, Clinton, Essex, and St. Lawrence counties.
Northern Herkimer, Hamilton, and Warren counties, including Old Forge and Glens Falls, are also under a fine particulate advisory with the same timeframe. 'When pollution levels are elevated...the New York State Department of Health recommends that individuals consider limiting strenuous outdoor physical activity to reduce the risk of adverse health effects,' 'People who may be especially sensitive to the effects of elevated levels of pollutants include the very young and those with pre-existing respiratory problems such as asthma or heart disease. 'Those with symptoms should consider consulting their personal physician.'
In Michigan, St Clair, Livingston, Oakland, Macomb, Washtenaw, Wayne, and Monroe counties, including cities like Port Huron, Pontiac, Detroit and Ann Arbor are under advisories. However, a statewide Air Quality Alert for fine particulate matter put in place on Monday remains in effect. The Minnesota Pollution Control Agency has issued air quality alerts for northern Minnesota, affecting millions of residents.
The alerts cover northeast and northwest/north central Minnesota, with varying levels of concern based on the Air Quality Index (AQI), including counties like Koochiching, St. Louis, Cook, Lake, and Itasca, and cities such as International Falls, Ely, Duluth, Hibbing, and Grand Marais 'Light winds will allow existing wildfire smoke across northern Minnesota to linger into this evening and overnight,' the NWS said. 'Concentrations are expected to be highest along and near the shores of Lake Superior. An additional round of heavy surface smoke from wildfires across southern Canada is expected to transport into northern Minnesota on Tuesday. In Illinois, the Air Pollution Action Day covers McHenry, Lake, Kane, DuPage, Kendall, Grundy, Northern Cook, Central Cook, Southern Cook, Northern Will, Southern Will, and Eastern Will counties.
Similarly, northwest Indiana's Air Quality Action Day includes Lake, Porter, Newton, and Jasper counties, encompassing Gary, Hammond, Merrillville, Portage, and Valparaiso. Ozone levels here are also expected to be unhealthy for sensitive groups The Vermont Agency of Natural Resources and the Maine Department of Environmental Protection's Bureau of Air Quality have issued advisories, respectively, affecting millions in the northeastern US. In Vermont, an Air Quality Health Advisory for fine particulates with an AQI approaching or exceeding 151 ('Code Orange') is in place until midnight for Caledonia, Addison, Chittenden, Franklin, Essex, Grand Isle, Lamoille, Orange, Orleans and Washington counties. The advisory in Maine, which lifts at 11pm, covers Northwest Aroostook, Northeast Aroostook, Northern Somerset, Northern Piscataquis, Northern Penobscot, Southeast Aroostook, Central Piscataquis, Central Penobscot, Southern Piscataquis, and Northern Washington counties. Pictured: A helicopter drops water on the Dryden Creek Wildfire just north of Squamish, British Columbia, Canada.