Massive Surge in US Wildfire Smoke Chokes Air Quality Progress for Tens of Millions

After decades of progress in cutting down on air pollution via regulations put in place by laws like the Clean Air Act, researchers on Thursday said that more frequent and intense wildfires are responsible for a major reversal of that advancement, with tens of millions of Americans now breathing in potentially toxic smoke each year.

Researchers at Stanford University found that the number of people impacted by "extreme smoke days," during which air quality is considered unhealthy for all age groups and populations, has increased by 27 times over the past decade, with 25 million exposed to hazardous air quality on at least one day in 2020.

"As the globe warms, wildfires and associated air pollution are expected to increase, even under a low emissions scenario."

Between 2006 and 2010, extreme smoke days were rare, but they rapidly became far more commonplace between 2016 and 2020, with more than 1.5 million people in the U.S. regularly facing air quality deemed dangerous.

"There's been really dramatic increases in wildfire smoke as air pollution, in some places fully reversing the impact of the Clean Air Act," Marshall Burke, a scientist at Stanford University and co-author of the study, which was published in Environmental Science and Technology, told The Guardian. "It's been remarkably quick. Our air pollution regulations are not designed to deal with this. It's a worrying problem."

Wildfire smoke has increased the level of particulate pollution in the air, according to the study. The researchers measured the presence of PM 2.5--particles which are one-thirtieth the size of a human hair--and found that wildfire smoke is responsible for an additional five micrograms of such particles in the air in parts of the western United States.

Air conditions this week forced public health experts in Seattle to advise older adults, children, and people with heart or lung disease to limit their outdoor activities.

"The new summer on the West Coast," wrote climate journalist Emma Pattee in an essay in The New York Times Thursday, means "checking the air quality before going on a hike, getting anxious on a windy day because it means the fires are going to get worse. Scheduling camping trips, swimming lessons, and soccer camp and then canceling them as smoke interferes."

"For children growing up in the American West, it isn't a question of what you want to do outdoors; it's a question of whether you can even go outside," she wrote.

In some parts of the U.S. West, the increase in PM 2.5 has erased progress that was made by regulating pollution that came from factories, vehicles, and other sources.

The rise in extreme smoke days has occurred as wildfires have grown in size and intensity. Six out of seven of the largest fires in California's history have occurred in the last two years.

The researchers found that better forest management is part of the solution to the West's worsening wildfire crisis, but that "drastic cuts to greenhouse gases" are also needed, according to The Guardian.

In 2016, scientists at the University of Idaho and Columbia University found that the human-caused climate crisis and global heating were behind the doubling of forest fires over the previous three decades.

Extreme heat and drought caused by the climate crisis are expected to drive a continued increase in wildfires over the next several decades, with large fires expected to become 30% more frequent by 2050 and 50% more frequent by the end of the century.

"As the globe warms, wildfires and associated air pollution are expected to increase, even under a low emissions scenario," said Petteri Taalas, secretary general of the World Meteorological Organization, earlier this month. "In addition to human health impacts, this will also affect ecosystems as air pollutants settle from the atmosphere to Earth's surface."

Exposure to wildfire smoke has been linked to higher risk of heart attacks and has been blamed for 3,000 deaths in California in people over the age of 65 in 2020. In May, scientists at McGill University published research showing that people living within 31 miles of wildfires over the past decade were 10% more likely to develop brain tumors and 5% more likely to be diagnosed with lung cancer than people who lived farther away.

Wildfire smoke, however, can reach areas far away from its source. Last week meteorologists at The Washington Post reported that a "light haze" over Washington, D.C. was "indeed from the western wildfires," and in July 2021, air quality in New York City was among the worst in the world as wildfire smoke drifted all the way across the country.