Plumes of Smoke From Fires in the North American West Stretch Across the Continent

Particle pollution is affecting air quality in cities thousands of miles away

A map showing how particulates from wildfires in Canada and the Western U.S. has spread to the East Coast
The billowing smoke resulted from nearly 300 wildfires currently ravaging British Columbia, Canada’s westernmost providence, and 80 fires blazing through states in the Western United States. Joshua Stevens/NASA Earth Observatory

As regions across the western United States and parts of Canada face an intense early wildfire season, its effects are being witnessed on the opposite side of the country as far east as the Atlantic Ocean.

Skylines from Boston to North Carolina faded behind an eerie haze, and air quality alerts urged residents thousands of miles away from the wildfires to stay inside as winds blew the smoke eastward, reports Sarah Gibbens for National Geographic.

“What they’re experiencing on the East Coast from our West Coast fires shows it’s a nationwide and a global problem,” says Mary Prunicki, Stanford University’s director of air pollution and health research, to National Geographic.

The billowing smoke resulted from nearly 300 active wildfires currently ravaging British Columbia, Canada’s westernmost providence, and 80 fires blazing through the American west. The largest fire is Oregon’s Bootleg Fire, which had already charred 400,000 acres, or roughly an area nine times the size of Washington D.C, per National Geographic.

Ignited by a lightning strike on July 6, the Bootleg Fire was so large it created its own weather, prompting even more lightning and releasing vast amounts of smoke, reports Nadja Popovich and Josh Katz for the New York Times. The fire threatened a total of 5,000 homes, and 2,000 households had to evacuate, reports Gillian Flaccus and Sara Cline for the Associated Press.

Satellite images released on July 23 by NASA’s Earth Observatory revealed the extensity of the smoke’s reach from the various wildfires. The images from July 20 and 21 displayed a band of smoke traveling eastward and particulate matter concentrations, or soot, masking North America, reports Harry Baker for Live Science.

Particulate matter (PM), or particle pollution, are a mix of liquid droplets and particles of dust, dirt, soot, or smoke that can be seen with the naked eye. Particulates are directly released into the air from smokestacks, fires, construction sites, and unpaved roads. Some of the particles can be so tiny that they can be inhaled. PM less than ten micrometers in diameter can only be seen using a microscope. These tiny particles can reach deep into the lungs, pass into the bloodstream, and cause severe respiratory illness and distress, National Geographic reports.

PM less than 2.5 micrometers in diameter (PM2.5) poses the greatest health risk. Breathing excessive amounts of PM2.5 increases the risk of asthma attacks, strokes, and heart attacks, National Geographic.

Particulate matter levels are measured using the Air Quality Index (AQI), with a scale ranging from 0 to 500. Any values above 100 are considered unhealthy. In New York City, AQI levels reached above 170, a level unsafe for sensitive populations with existing respiratory conditions and healthy people, reports Live Science. Air quality in cities from Toronto, New York, and Philadelphia also reached unhealthy PM levels, the New York Times reports.

“We fully expect that you’re going to see more situations where smoke, from fires occurring farther away, is going to travel long distances and affect people in other parts of the country,” Jesse Berman, a University of Minnesota air quality expert, tells the Associated Press. “I would not be surprised at all if these events did become more frequent in the future.”