Millions Exposed to Toxic Wildfire Smoke as Fires Burn Through Los Angeles Area

The Dangers of Wildfire Smoke

Millions of people across the Los Angeles area are being exposed to wildfire smoke as fires burn through homes and vehicles. The fires in January 2025 have burned thousands of structures along with the building materials, furniture, paints, plastics, and electronics inside them.

When materials like these burn, they can release toxic chemicals with the potential to harm people breathing the air downwind.

What’s in the Smoke?

A 2023 study of smoke from fires in the wildland-urban interface – areas where urban neighborhoods bleed into the wildlands – found it contained a vast array of chemicals harmful to humans. They include hydrogen chloride, polycyclic aromatic hydrocarbons, dioxins, and a range of toxic organic compounds, including known carcinogens such as benzene, toluene, xylenes, styrene, and formaldehyde. The researchers also found metals in the smoke, including lead, chromium, cadmium, and arsenic, which are known to affect several body systems such as the brain, liver, kidney, skin, and lungs.

Short-Term Effects

The short-term effects of exposure to smoke like this can trigger asthma attacks and cause lung and cardiac problems.

Long-Term Smoke Exposure is Increasing

Nationwide, the acreage burned in wildfires in the U.S. has nearly doubled each decade since 1990. That is changing how people are exposed to wildfire smoke.

Communities have found themselves blanketed in smoke for days and weeks at a time increasingly often. In 2023, massive wildfires in Canada repeatedly spread thick smoke into many U.S. communities. Controlled burns which firefighters set to clear away flammable brush and reduce the severity of future wildfires, also add smoke to the air.

Dose, Duration, and Frequency Matter

When scientists study the health risks of wildfire smoke, they tend to use analysis methods that were developed to assess health effects caused by low-level, chronic, urban air pollution exposures – picture car exhaust or smokestack emissions. However, these approaches fail to capture the dynamic and intense nature of wildfire smoke.

Researchers suspect there are differing consequences for people exposed to smoke at varying intensities and durations. Repeated exposure to wildfire smoke may also have compounding health effects over time.

Improving Understanding of Long-Term Effects

To study the long-term impact of wildfire smoke, scientists need to know how much smoke people were exposed to, for how long and how often. That’s not an experiment anyone can conduct on humans in a lab, but the data can be gathered from communities being affected by wildfires.

Right now, however, this kind of data collection is rare.

Conclusion

Improving understanding of the long-term effects of wildfire smoke will require thinking differently about smoke. If epidemiologists can begin clearly defining the negative health effects from wildfire smoke exposure in terms of dose, duration, and frequency in their studies, taking into account the dynamic and episodic nature, then toxicologists can model these human experiences in animal experiments. These experiments would have the potential to improve the understanding of the long-term health risks and then help scientists develop effective guidelines and strategies to mitigate harmful exposures.

FAQs

Q: What are the health effects of wildfire smoke?

A: The health effects of wildfire smoke can include asthma attacks, lung and cardiac problems, and exposure to toxic chemicals.

Q: Is wildfire smoke safe to breathe?

A: No, wildfire smoke is not safe to breathe. It can cause serious health problems and even be deadly.

Q: Can I take precautions to avoid wildfire smoke?

A: Yes, you can take precautions to avoid wildfire smoke. Stay indoors, keep windows and doors closed, and use an air purifier to remove pollutants from the air.