Matthew Cappucci and Jason Samenow
Smoky scenes — so common in California during recent summers — are now paying the eastern United States an unwelcome, improbable and toxic visit.
A thick veil of Canadian wildfire smoke is spreading south over much of the Midwest, Ohio Valley, Northeast and Mid-Atlantic, bringing milky-white skies and dangerous air pollution to the most populous corridor of the country. Fine particles contained within the smoke, hazardous to breathe, have prompted air quality alerts for tens of millions of people from South Carolina to New Hampshire.
As of Tuesday evening, New York City had the worst air quality in the world among major cities. Scenes from social media and web cameras showed the sky above Manhattan tinged a reddish-orange hue, drawing comparisons to Mars.
“If you’re a New Yorker with heart or breathing issues, be careful when you’re outdoors,” said the City of New York in a tweet signed by the mayor. “Smoke from wildfires in Canada is impacting our city’s air, so an Air Quality Health Advisory has been issued. Try to limit outdoor activities today to the absolute necessities.”
On Wednesday morning, hazardous air quality reached Washington, D.C., where the air smelled like smoke and reduced visibility to two miles.
In some places, air quality measurements are the worst on record. Marshall Burke, a professor of environment at Stanford University, tweeted that this event is the “[n]ear worst or worst event” in the past two decades or so, based on smoke particle data.
New Haven, Conn., posted its worst air quality on record Tuesday while EPA measurements showed hazardous smoke pollution enveloping much of New York state and southern New England.
Where are the wildfires causing the smoke?
The source of much of the smoke pouring into the region is Quebec, Canada. Most broke out in the past week. Across Canada, there are 416 active fires, 240 of which the Canadian Interagency Forest Fire Center lists as “out of control.”
The wildfires cropped up beneath a well-predicted “heat dome,” or zone of high pressure, which brought sinking air and warm, dry conditions that broke records for the time of year and location.
Low pressure swirling clockwise over Nova Scotia, meanwhile, is making for a conveyor belt of northerly winds that is pumping the smoke south over the Great Lakes, Northeast and Mid-Atlantic.
Wildfire smoke, air quality and your health
Wildfire smoke can travel great distances, with particulates small enough to enter the bloodstream through your lungs if inhaled. If you’re in an area affected by smoke, limit your outdoor activities (especially when exercising) and wear a good mask outside that can filter fine particles.
Where is the smoke and where is it worst?
Satellite imagery Wednesday morning showed smoke covering the Northeast and extending into the Carolinas. The thickest extended from lakes Erie and Ontario to southern New York state.
That said, hazardous air quality reached as far west as Minnesota on Tuesday, according to AirNow.gov, and into the Carolinas Wednesday morning.
Environmental agencies plastered air quality alerts across an expansive swath of the Northeast and Mid-Atlantic, in effect into Wednesday, cautioning that “sensitive individuals, including those with heart or lung disease, the elderly, and the young should limit strenuous activities and the amount of time active outdoors.”
The alerts cover southeast Michigan, parts of Ohio, northern South Carolina, much of North Carolina, northern Virginia, much of Maryland, Delaware, eastern Pennsylvania, New York, Vermont, Massachusetts, Connecticut, Rhode Island and western New Hampshire.
During Tuesday, some of the worst air quality was concentrated in western New York into Quebec and Ontario, where code red and purple conditions were prevalent, meaning air quality was hazardous for all populations.
Jase Bernhardt, a professor of meteorology at Hofstra University, determined that the Air Quality Index in Syracuse, N.Y., was the worst since reliable records began in 1999.
Particle pollution in Detroit and New York registered at the highest and second-highest levels, respectively, since 2006, Stanford’s Burke found.
Meanwhile, forecasters at the Weather Service in Burlington, Vt., called the smoke situation “uncharted territory,” having never dealt with it before. “[W]e are learning and adapting as the event unfolds,” they wrote in a discussion.
How long will it last?
With no end in sight to the fires, the question of how long the smoke lingers comes down to wind direction.
Wednesday into Thursday, an even worse round of wildfire smoke could waft south out of Canada on the backside of a north-to-south-moving cold front. Pennsylvania, New York state and the Mid-Atlantic — including major metro areas such as Philadelphia, Newark, New York, Baltimore, Washington and Richmond — are likely to see very poor air quality. Outdoor recreation would probably be hazardous.
Winds will become more northwesterly Friday into Saturday. While that won’t fully clear the smoke, it will bring a reduction in the concentrations of fine particulate matter. Visibilities, sky conditions and air quality will improve somewhat.