The ashes of the Dixie fire cast a pall 1,000 miles from its flames — all the way to Utah

Taylorsville, Calif. • Captured by an astronaut’s camera, the Dixie Fire appears as a thick and sickening miasma pouring from the Earth’s surface. At its center in the eastern mountains of California, the fire is devouring acre after acre of rugged wildland to become the second-largest blaze in the state’s history.

But Dixie and other megafires in the West have left a footprint much larger than the evergreen forests they level and the towns they decimate.

Summer after summer, California, a global leader in battling air pollution from vehicles, sends giant clouds of haze filled with health-damaging particles across the country. Even as far as Denver, 1,100 miles to the east, the fire has helped create a pall of noxious smoke during an already scorching summer.

By one measure, wildfires — intensified by drought and climate change — are the largest source of potentially deadly air pollution in California. And in recent weeks, the accumulating haze and smoke from California’s fires and high ozone levels have turned the air in Salt Lake City and Denver into some of the dirtiest in the world, more harmful than Delhi’s or Beijing’s on many recent days.

Smoke from wildfires across western Canada, Oregon and California has stained the skies and fouled the air as far away as Iowa, Minnesota and even New York City. Recent research suggests that the smoke may actually grow more toxic as it ages, undergoes chemical changes and blows across the country, reacting with sunlight and other molecules floating in the air. Over time, smoke may form reactive compounds that can be especially damaging to the body once they are inhaled.

“It gets worse with age,” said Mary Prunicki, director of air pollution and health research at the Sean N. Parker Center for Asthma and Allergy Research at Stanford University.

The air quality got so bad last week in Utah that several schools decided to call off sports practices and outdoor activities. Provo High School canceled a game on Friday night. Summer camps in Washington state were suspended or canceled.

Twenty-seven days after igniting, the Dixie Fire has yet to claim any lives, although three firefighters have been injured and 433 homes and businesses have been destroyed. What sets the Dixie Fire apart from the megafires of previous years is the vast area it has torn through in the mountains northeast of the state capital, Sacramento. With 489,287 acres burned, the fire is still only 21% contained.

And the exhausted firefighters battling the Dixie Fire in and around Gold Rush towns are warning that the season of smoke and fire could grip the drought-stricken West for months to come.

“I have no doubt in my mind that it’s just getting started,” said Matt Sanders, a fire engine captain.

In the remote mountain communities that dot Plumas County, a thinly populated county near the border with Nevada, choking smoke hangs thick in the air. The power is out, and in some places water is scarce both for firefighting and drinking. Residents who have decided not to evacuate are collecting meat and groceries from their neighbors’ fridges. Others are isolated, holding out for deliveries from community firefighters of food, medicine and gas.

One family said they had attempted to evacuate, but were forced to return back to their property. “My dad has dementia and if we leave the area he just wants to come home,” said Jack Cunningham, who was caring for his parents at their home in the forest near Taylorsville. His mother requires oxygen that is being powered by a generator.

“We’ve been testing her to see how long she can stay off oxygen, right now it’s about 30 minutes,” said Cunningham’s sister, Dena Cunningham, adding that their plan, should they have to evacuate, was to take two portable oxygen tanks, lasting 45 minutes each.

In parts already ravaged by fire, the forests are eerily quiet. Now and then a burned tree cracks and falls. Stunned deer wander the rubble. People sleep in trailers in parking lots, dazed by the displacement.

Around Taylorsville, a tightly knit community, people have been preparing for the fire for weeks, helping one another dig trenches with bulldozers, set up irrigation lines and spray homes. Many ranchers have packed their most precious belongings and stored them in cattle trailers in irrigated fields where they hope they will be safe if the fire comes down from the mountains. People’s days revolve around tracking the fire’s every move. The sounds of generators fill the air.

The giant plumes of smoke belched by the fires rise into the atmosphere like a huge funnel and drift eastward. Data from the California Air Resources Board show that wildfires are the largest source of the tiny air pollution particles known as PM 2.5, which can cause lung and heart diseases. The fires last year produced hundreds of times as many of these particles as passenger vehicles did in the state.

As the smoke crosses the continent it brings with it anxiety for parents, the elderly and those with respiratory conditions.

In the rural Utah town of Vernal, Heidi Pilling spent Monday morning keeping a concerned eye on the 29 children in her care at Little Peeps day care as they played by the sandbox.

Six of the children have asthma — as does Pilling — and she said days of unhealthy air stung her eyes and throat and made it hard to take deep breaths. They normally like to spend two to three hours outside on sunny summer days, but Pilling has had to develop fallback plans like indoor yoga and dance parties for the multiplying days when the air just feels too toxic to breathe for long.

“If they react badly, we go in,” she said Monday. “Today it’s the worst it’s been. It’s just gray, gray, gray.”

Kirk Chambers, the head coach of the Provo High School Bulldogs football team, said he decided to scrap last Friday’s game after smoke wafting over Utah piled up against the Wasatch Mountains and sent the color-coded air-quality dials on his phone from orange to red to a sickly purple. “If you were out in it for just a half-hour, you felt completely crummy,” he said. More and more, this is what the reality of smoky summers looks like: Scrapped games, students with asthma unable to play safely and a last-minute scramble to find indoor fields to practice on.

Wildfire smoke is one of the more dangerous air pollutants — a gale of burned trees, house paint and home insulation, chemicals and more — and has the power to send people far from fire lines to the emergency room with asthma attacks, strokes and heart attacks, researchers said.

“We care a lot about particles in the atmosphere because they kill people and they send people to the hospital with serious diseases,” said Anthony Wexler, director of the Air Quality Research Center at the University of California, Davis.

Over the long term, he said, smoke particles may also stunt the growth of children’s lungs.

Smoke particles can accelerate the melting of snow, too, and interfere with weather patterns, generally leading to less rainfall.

But the full effects of having such huge wildfires so often are still being discovered, Wexler said.

“We don’t understand the full impact,” he said. “This used to be unprecedented and now it’s annual.”

On Sunday morning, residents of Taylorsville who had met for a community breakfast at the fire station said that they felt they were living in a kind of purgatory as they waited to see if the fire would reach them, and in the meantime, suffering the choking effects of the haze.

“I’m breathing a lot of smoke,” said Lee Newbill, 65, a rancher who had pulled up outside the station in his pickup truck. “Never had a smoke in my whole life,” he added. “I’m making up for it now.”

This article originally appeared in The New York Times.