Roya Bahreini

Where there’s fire, there’s smoke

tomwt — Tue, 26 Aug 2025 22:49:27 +0000

Where there’s fire, there’s smoke tomwt Tue, 08/26/2025 - 15:49 More CNAS in the Media Emily Dieckman | Eos August 26, 2025

EOS - Gale Sinatra and her husband fled their Altadena, Calif., home on 7 January with little more than overnight bags, taking just one of their two cars.

“We thought we were going to be gone overnight,” Sinatra said. “We thought they’d get the fire under control and we’d get back in.”

When the couple did return, weeks later, it was to dig through the rubble of their former home, burned to the ground by the Eaton Fire.

Though they escaped with their lives, health hazards were not behind Sinatra, her husband (who chose not to be named for this story), and others from their neighborhood. The Eaton and nearby Palisades fires filled the Los Angeles Basin with a toxic haze for days, and cleanup efforts threatened to loft charred particles long after the fires were out.

Teams of scientists from across the country, along with community members, monitored air quality in the weeks following the fire, seeking to learn more about respiratory health risks and inform community members about how to protect themselves.

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“From mattresses to carpets to paint to electronics, everything like that burns,” said Roya Bahreini, an environmental scientist at the University of California, Riverside (UCR). Bahreini is also co–principal investigator of the Atmospheric Science and Chemistry Measurement Network (ASCENT), a long-term air quality monitoring project led by the Georgia Institute of Technology, UCR, and the University of California, Davis (UC Davis).

ASCENT, which launched in 2021, has stations across the country, including three in Southern California. During the January fires in Los Angeles, which tore through not only Altadena (an unincorporated inland community) but also neighborhoods along the coast, these stations detected levels of lead, chlorine, and bromine at orders of magnitude higher than usual.

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How scientists rushed to make L.A.’s actual air quality available on your phone

tomwt — Wed, 29 Jan 2025 19:26:55 +0000

How scientists rushed to make L.A.’s actual air quality available on your phone tomwt Wed, 01/29/2025 - 11:26 More CNAS in the Media Kristin Toussaint | Fast Company January 29, 2025

FAST COMPANY - As fires burned tens of thousands of acres across Los Angeles County, officials were warning residents that the air was a “toxic soup” of pollution—fueled by the fact that not only vegetation but cars, buildings, homes, and all the plastics and electronics inside them were going up in flames.

But to some residents’ surprise, the Air Quality Index (AQI) on their phones didn’t relay that same message. That’s because AQI doesn’t capture the full scope of air pollution—which, during the fires, was made up of toxins including lead, chlorine, and bromine. To give residents a fuller picture of what exactly was in the air around L.A., scientists with an air monitoring project made their advanced air pollution measurements available to the public.

What doesn’t AQI capture in air pollution?
The Environmental Protection Agency developed the AQI to measure five major pollutants: ground-level ozone, particle pollution (also called fine particulate matter or PM2.5, meaning particles that are 2.5 microns or less in size), carbon monoxide, sulfur dioxide, and nitrogen dioxide. PM2.5 and ozone tend to be the primary pollutants. The index gives all this air pollution a value based on the total mass concentration.

That means the general AQI reading can lack specificity, says Roya Bahreini, a professor of atmospheric science at University of California Riverside and a co-principal investigator of the Atmospheric Science and Chemistry mEasurement NeTwork, or ASCENT project. It’s also missing certain toxins that may be released during events like urban wildfires. “Just looking at the value of PM2.5 cannot tell you how toxic the air is.”

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Why does the West Coast’s sky look like literal Hell right now?

ilseu — Thu, 10 Sep 2020 05:50:03 +0000

Why does the West Coast’s sky look like literal Hell right now? ilseu Wed, 09/09/2020 - 22:50 More CNAS in the Media Jane C. Hu | Slate September 09, 2020

SLATE - You know things have gone off the rails if people are arguing about whether it looks like Mars or Venus where they live. In case you missed it, fires are burning across the Western U.S., and thick wildfire smoke has enveloped regions of California and Oregon. As a result, residents of Salem and San Francisco are experiencing eerie orange-red skies.

As a result, air quality is also terrible across the West Coast. In Washington, where I live, the skies are hazy but mostly blue. Yet the Environmental Protection Agency’s numbers indicate worse air quality than in San Francisco, where the sky is completely red. That’s likely because the air quality index is a measure of surface air quality, says Roya Bahreini, an atmospheric scientist at University of California, Riverside. “The smoke from the wildfires can get injected higher in the atmosphere,” she says. In other words: That smoke might not affect surface-level measures of air quality, but it can, of course, still blot out the sun and filter light. And according to Daniel Swain, a UCLA climate scientist, smoke and ash are now traveling up to 50,000 feet—“20,000 above cruising altitude of jet airliners,” he wrote in a recent tweet. “Dense smoke throughout entire atmospheric column is blocking nearly all sunlight at surface.”

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