A significant plume of wildfire smoke originating from Canada has begun to drift into the United States, impacting air quality across at least 17 states. The smoke, carrying fine particulate matter known as PM2.5, is expected to affect much of the Upper Midwest and Northeast throughout the week.
Meteorologists predict that states including Minnesota, Wisconsin, Michigan, Pennsylvania, New York, and the entire New England region will experience the densest smoke. Major metropolitan areas such as New York City and Philadelphia could see air quality issues on Wednesday and Thursday.
The US Environmental Protection Agency (EPA) links exposure to PM2.5 to various health problems, including aggravated asthma, reduced lung function, irregular heartbeat, heart attacks, and premature death for individuals with pre-existing heart and lung conditions. Officials advise sensitive groups to limit outdoor activity and consider wearing masks if venturing outside when air quality is poor and smoke is visible or smells strong.
The current influx of smoke is attributed to over 800 active wildfires burning across Canada, particularly in the Northwest Territories, Saskatchewan, Manitoba, Ontario, and Quebec. By July, two million acres have already burned in Canada, a figure comparable to entire wildfire seasons in previous years. While climate change may be a contributing factor to the increase in wildfires, a lack of aggressive fire and land management in vast, rural Canadian areas also allows fires to burn with less suppression.
While the smoke is expected to impact air quality, experts suggest the effects may be less severe than in 2023, when historic wildfires led to widespread orange skies across the US. However, pockets of unhealthy or very unhealthy air quality are possible in the northeastern Great Lakes region and parts of the Northeast through Thursday.
The intensity of the smoke's impact on ground-level air quality depends on how low the plume settles. Currently, much of the smoke is at higher altitudes, creating hazy sunshine. When it mixes down closer to the surface, air quality deteriorates. This smoke is arriving as parts of the Northeast are already dealing with heat and humidity from a heat dome, which could exacerbate the unpleasantness of smoky conditions.
The National Weather Service has warned that millions of Americans could see reduced air quality this week due to Canadian wildfires. AccuWeather Vice President of Forecasting Dan DePodwin noted that air quality can fluctuate, making the impact unpredictable hour by hour. He advised that it is prudent to anticipate at least a day or two of reduced air quality, with the possibility of it becoming unhealthy.