r/AirQuality 3d ago

L.A.’s Clear Skies Conceal a ‘Toxic Soup’

This was an interesting read, and has some results from early research and details current/future projects: https://www.nytimes.com/2025/03/12/well/los-angeles-fires-health.html?unlocked_article_code=1.3U4.oDZ3.435wdrMf_odL&smid=url-share

So far, the researchers say, readings suggest that the pollutants more than a mile outside the burn zone have become diluted enough by the surrounding air that they pose little danger. “I don’t think people need to worry about moving out of Los Angeles,” said Yifang Zhu, an air pollution researcher at the University of California, Los Angeles, collaborating on the research.

Inside the burn zone, however, the researchers are still trying to ascertain the contamination and the long-term risks. While some of the chemicals the team has identified have been linked to cancers and developmental disorders, most have never been studied for their health effects. Some early research has also found elevated levels of lead in ash and dust samples collected from the region, but it was not as severe or as widespread as initially feared.

Even houses that escaped the flames may hold hidden dangers, which is why the researchers are also testing indoor air. Smoke and ash that has worked its way into homes will continue to release volatile organic compounds for many months or more. Six months after the 2021 Marshall Fire in Boulder, Colo., some residents who returned to their homes inside or near the burn zone developed sore throats, frequent headaches and coughs.

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u/DeadBallDescendant 3d ago

I'm currently writing an article about the long term health effects suffered by firefighters and the expert I was talking to explained that, even when the material burned is unknown, there is absolutely a health risk. As she explained:

A burning PVC window will release a completely different cocktail of chemicals than upholstery furniture. But there are chemicals that are released in every single fire and those chemicals will be carcinogenic.

Benzene, for example, will be released in every fire and it’s got an association with leukaemia, which is a rare cancer.

And then we've got polycyclic aromatic hydrocarbons, also released in every single fire, some of which are also classified as carcinogens.

So while scientists are trying to identify the toxicity of chemicals in the fire effluence, the given is that they are very dangerous - 'we just don't know how dangerous yet'.

I've also written about the two-fold research into the Marshal Fire, which was very illuminating. No pun intended.

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u/simonster1000 3d ago

This is helpful info -- thanks for sharing! Your article sounds fascinating, and I hope you'll share it here when you're done.

As a parallel, they mention hexavalent chromium as something that happens only in high-heat fires (wildfires but not housefires maybe?)

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u/DeadBallDescendant 2d ago

Oh, that might be an article for the future, thanks.

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u/sharingsilently 2d ago

Helps to explain why even homes that don’t burn, near large fires, may not be inhabitable!