How Dangerous Is Wildfire Smoke?

Monday: Ahead of a likely severe wildfire season, researchers suggest pollution from wildfires is more toxic than pollution from other sources.,


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ImageFire crews cleared brush during the El Dorado Fire in Angelus Oaks last September.
Fire crews cleared brush during the El Dorado Fire in Angelus Oaks last September.Credit…Eric Thayer for The New York Times

Good morning.

Last week, the state’s top legislative leaders unveiled a plan to spend more than half a billion dollars on efforts aimed at protecting the state from catastrophic wildfires.

The plan builds on the governor’s proposal in January to spend $1 billion on wildfire prevention and resiliency efforts and includes money for things like vegetation thinning and home fixes meant to keep them from burning.

“With California facing another extremely dry year, it is critical that we get a head start on reducing our fire risk,” the three leaders — Gov. Gavin Newsom; Toni G. Atkins, the State Senate’s president pro tempore; and Anthony Rendon, the Assembly speaker — said in a statement.

That’s not an exaggeration.

My colleague Vindu Goel recently reported that this year has been so dry that two state agencies have warned there could be water supply cuts to homes, businesses and farmers. The San Francisco Chronicle reported that researchers who analyze moisture levels in plants have been shocked by some of what they’ve been seeing.

[Catch up on last year’s devastating fire season and what made it that way.]

In other words, California urgently needs to make progress before fire season hits.

Given the record-obliterating blazes we saw during last year’s season — which started really early — it’s easy to summon a sense of urgency.

More than five million acres burned across the West, exhausting firefighters and leaving policymakers scrambling to implement solutions long sought by experts, including Indigenous fire practitioners, like increasing the number of acres treated with prescribed burns. (That’s when fires are intentionally set under conditions when the blazes will be manageable, to clear overgrown plants that could fuel an out-of-control conflagration.)

But one factor that experts say has been less understood is how wildfire smoke that spread across the state, fouling the air for millions of Californians for weeks, could cause negative health effects, both during fires and in the longer term.


An orchard on the outskirts of Kettleman City in this San Joaquin Valley this month.Credit…Frederic J. Brown/Agence France-Presse — Getty Images

The connection between the tiny particles that make up air pollution and respiratory health problems is unambiguous, experts say.

But how dangerous is the wildfire smoke that turned the skies of the Bay Area an unsettling ocher shade compared with more ambient pollution from sources like car exhaust? That has been less clear.

Recently, though, a study by researchers with Scripps Institution of Oceanography at the University of California, San Diego, found that fine particulate matter from wildfire smoke can be several times more harmful to respiratory health than from other sources.

The study’s authors analyzed 14 years of Southern California hospital admissions data, lining it up with smoke plume and wind patterns.

When an increase in pollution was attributed to wildfire, hospital admissions related to respiratory health increased between 1.3 percent to 10 percent, compared with 1 percent when the same pollution increase was attributed to other sources.

Whereas lab research had already suggested that wildfire smoke could be more dangerous, Rosana Aguilera, one of the new study’s co-authors, told me recently that their work takes “more of an epidemiological point of view.”

Still, she said, the conclusion was the same: “Wildfire smoke is more toxic than the same size of fine particles that might be found in ambient pollution.”

So what does this mean?

Dr. Aguilera said that air quality regulations and measurements should better account for the different sources of pollution.

“And of course ambient pollution is still a problem,” she said. But increases in wildfire smoke from fires driven by climate change could cancel out some of the hard-won decreases in pollution from vehicles and other types.

Tom Corringham, another co-author of the study, said all of that should inform policy.

For example, farmworkers, who have been particularly vulnerable throughout the pandemic, should be given N95 masks, even when there isn’t a virus spreading.

Both said they hoped to continue studying the health effects of wildfires over time.

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  • On average over the past year, seven Covid-related deaths each day were reported in America’s prisons, jails and detention centers. Thousands have been infected, including many who have not been convicted of crimes in California jails. Experts say many cases were preventable. [New York Times]

  • California’s vaccine supply could decrease this week, just as demand is expected to surge when eligibility expands. [The San Francisco Chronicle]

  • Over the last year, businesses were closed and allowed to reopen under coronavirus restrictions. Here’s a look back at the thousands of rule changes that affected businesses owners as they navigated reopenings across the state. [Los Angeles Times]

  • Lots of restaurants want to reopen but they can’t find employees to staff them. Owners say the main reason is that there are simply many more job openings than available workers. [New York Times]


A Black Lives Matter activist, Keyanna Celina, chanted during a counter demonstration to an anticipated “white lives matter” rally at Huntington Beach Pier on Sunday.Credit…Allison Zaucha for The New York Times
  • Crowds of counterprotesters showed up to oppose a planned “white lives matter” rally in Huntington Beach: “I’m here to help keep the peace and show people we are not violent rioters and also to reject the KKK and white supremacy.” [Orange County Register]

  • A Fresno police officer who had ties to the Proud Boys, the far-right extremist group that the authorities have said helped incite the Jan. 6 storming of the Capitol, has been fired. [Fresno Bee]

  • San Franciscans rallied in solidarity with India’s farmers. [KQED]

  • San Diego County supervisors delayed a vote to move forward a proposal to repeal a policy prohibiting the region’s 18 tribes from expanding their reservation, disappointing tribal leaders. [San Diego Union-Tribune]

  • In the latest episode of “Still Processing,” the co-hosts Jenna Wortham and Wesley Morris look at depictions of racist tropes and stereotypes in Disney’s catalog. The company has made recent efforts to atone for its past, but can it move forward without repeating the same mistakes? [New York Times]

  • California is set to lift all business restrictions on June 15. So when can we see live music again? [KQED]


Luna Trujillo dancing during an annual Dodgers opening day party in Los Angeles on Friday.Credit…Allison Zaucha for The New York Times

Over the weekend, baseball fans across the state caught some of their first glimpses of a post-pandemic — but still not normal — season.

The San Francisco Giants on Friday welcomed some 9,000 spectators to their home opener at Oracle Park, after fans showed proof of being vaccinated or a recent coronavirus test. And also on Friday, the world champion Los Angeles Dodgers also brought fans back to Dodger Stadium, although it had limited capacity.

California Today goes live at 6:30 a.m. Pacific time weekdays. Tell us what you want to see: Were you forwarded this email? Sign up for California Today here and read every edition online here.

Jill Cowan grew up in Orange County, graduated from U.C. Berkeley and has reported all over the state, including the Bay Area, Bakersfield and Los Angeles — but she always wants to see more. Follow along here or on Twitter.

California Today is edited by Julie Bloom, who grew up in Los Angeles and graduated from U.C. Berkeley.

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