Wildfire Smoke Is Showing Up Everywhere. It Can Be Fatal

There is a growing appreciation of the health threat posed by wildfire smoke. Above, smoke envelopes a church during the Palisades Fire in Los Angeles, California, in January 2025. Photo: CAL FIRE_Official via Flickr Creative Commons (CC BY-NC 2.0).

Backgrounder: Wildfire Smoke Is Showing Up Everywhere. It Can Be Fatal

By Joseph A. Davis

Wildfire smoke may be the smog of our time. Except it’s even harder to control. It’s sometimes fatal. And sometimes everywhere.

It’s one thing when an ominous orange sky smothers San Francisco, but quite another when it swallows New York.

Are you ready? It’s a whole new ball game.

You don’t have to be old to remember the photochemical smog smothering Los Angeles like it was yesterday — because we still have it sometimes today in many cities.

Some environmental journalists may not remember that LA smog was one of the key inspirations for the Clean Air Act of 1970, still the nation’s main air pollution control law, which we are still struggling to live up to.

 

Wildfire smoke from

far away is now plaguing

all parts of North America.

 

What’s new? Well, for one thing, wildfire smoke from far away is now plaguing all parts of North America. Not just Idaho.

For another, there is a growing appreciation of the health threat it poses. And climate heating is making it worse.

Wildfires used to be seasonal. Today, the season can go year-round. The fire that destroyed Pacific Palisades and other LA areas happened in early January.

And we now see wildfire smoke traveling huge distances: from Canada to our nation’s capital in D.C., for example. And today, D.C. may be getting smoke from fires in Virginia as it did in 2024. This, too, is new — the Appalachians have seen some awful fires in recent years.

Ask this: Can Congress and the White House see the problem through the smoke? We wouldn’t bet the ranch on that — yet — but a few more years may make it inevitable.

 

Where’s the harm in wildfire smoke?

It’s bad enough when wildfire destroys your town. But today, the smoke from distant wildfires is actually killing people, especially those with lung conditions and other special vulnerabilities. That may include somebody’s grandmother.

Wildfire smoke is pollution: mostly small particles. Air quality experts call it PM 2.5 (particulate matter whose particles are less than 2.5 micrometers in diameter).

 

Burning forests or

grasslands have little

respect for the Clean Air Act.

 

If a factory smokestack were emitting it, it would be illegal. But since Mother Nature is emitting it, there’s very little we can do to stop it. Burning forests or grasslands have little respect for the Clean Air Act. On a bad day, wildfire smoke is much worse than the pollution from cars and industrial smokestacks.

But there’s more to it than particulates. Wildfire smoke contains carbon monoxide, nitrogen oxides, sulfur oxides and volatile aromatic compounds like formaldehyde, which cause cancer. When wildfires burn whole towns of human structures, the smoke and ash can contain even more hazardous and harmful chemicals.

And, of course, carbon dioxide, which adds to global warming. When the sky turns orange, few people are thinking about that.

Best estimates from 2021 put annual CO2 emissions from wildfire globally at about 1.8 billion tons — compared to 38 billion from fossil fuels and industry. Nonetheless, it adds up to positive feedback, since CO2 amps up the warming-caused wildfires that release more CO2.

But yes — wildfire smoke kills. A very good study by researchers at the Yale School of Public Health says so. It was published in the Proceedings of the National Academy of Sciences in 2024. Researchers looked at 3,108 counties in the United States from 2007 to 2020. They “found that PM2.5 in smoke contributed to approximately 11,415 non-accidental deaths per year in the contiguous U.S.”

 

Taking a historical perspective

So are wildfires natural or unnatural — or both? Are they good or bad? Preventable or inevitable? History offers some lessons.

If we look back 20,000 years, the Laurentide ice sheet covered the part of North America where we now worry about wildfires. It was glacial ice, in places two miles thick. Wildfires did not exist there. Today it’s gone.

By 1492, when Europeans arrived, much of that area had been replaced by boreal forest. That’s what burns today.

We like to think today’s wildfires are bad (they are). But historically, there have been worse. The Peshtigo Fire of 1871, just north of Green Bay, Wisconsin, killed 1,200-2,500 people. The Big Blowup of 1910 burned 3 million acres in Idaho and Montana in two days, killing 87.

Part of the problem today is that people have built homes and businesses in the urban-wildland interface. Despite recent disasters, they still are doing it.

 

Another part of the

problem is the way

people build houses

in fire-prone areas.

 

Another part of the problem is the way people build houses in fire-prone areas. In this year’s Palisades fire, it was the houses that were fueling the fire, not the vegetation. (No, 100-mph winds didn’t help.) Wood shingles don’t cut it. Better to go with metal roofs and mineral siding. Better yet: adobe. The technology is there.

The disastrousness of fires in modern history eventually led to a federal policy of immediate fire suppression during most of the 20th century. Feds were gung-ho. The “10 a.m. policy” followed by the feds sought to put out all wildfires by 10 a.m. the morning after they were discovered. Bad idea.

Today, governments rarely throw huge resources at huge fires in remote areas where almost nobody lives. There is growing respect for the “cultural burning” practices of the original Native American residents, who deliberately burned manageable, small stands to prevent larger fires.

Federal and state land managers today sometimes start prescribed burns to head off later disasters. There is growing understanding that some forest species actually need fire to reproduce.

 

What should be done in the meantime?

First: Don’t build in fire-vulnerable areas. Second: Build in places easy to evacuate. Third: Build houses that don’t burn.

As to the orange sky problem: It’s real pollution. So here are some things journalists should tell their audiences.

• Listen to the news and stay inside when they tell you to.
• Don’t go out and exercise in the smoke.
• Seal your house from smoke and turn off outside ventilation, if possible.
• Use high-performance filters in your HVAC system.
• Try indoor air purifiers.
• Set up at least one room in your house to be a low-pollution area. Even better, sleep there.
• Wear an N95 respirator mask, fitted right.
• If your family includes vulnerable people (like kids, mothers-to-be or elders with impaired breathing), you may want to evacuate.

Today, though, there may be no place to evacuate to. Another reason to face up to climate change and do something about it.

[Editor’s Note: For more on covering wildfire smoke, see TipSheets on making the story local and smoke’s health threats more generally, Reporter’s Toolboxes on wildfire smoke data, air quality monitors and tracking respiratory health, and a Feature on wildfire pollution-reporting rules. Also see other top wildfire stories from SEJournal and wildfire headlines from EJToday on our Topic on the Beat: Wildfire page.]

Joseph A. Davis is a freelance writer/editor in Washington, D.C. who has been writing about the environment since 1976. He writes SEJournal Online's TipSheet, Reporter's Toolbox and Issue Backgrounder, and curates SEJ's weekday news headlines service EJToday and @EJTodayNews. Davis also directs SEJ's Freedom of Information Project and writes the WatchDog opinion column.

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* From the weekly news magazine SEJournal Online, Vol. 10, No. 26. Content from each new issue of SEJournal Online is available to the public via the SEJournal Online main page. Subscribe to the e-newsletter here. And see past issues of the SEJournal archived here.