Researchers found harmful pollution can linger indoors long after skies clear, raising new concerns for families returning home after wildfires
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Wildfire smoke can keep polluting your home long after the flames are out, with harmful chemicals lingering indoors even when outdoor air looks clean again.
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Indoor air can sometimes be worse than outdoor air after a wildfire, as smoke-damaged materials continue releasing toxic VOCs like benzene and toluene.
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Families can take steps to reduce exposure, including smart ventilation, high-quality filtration, and careful cleaning to limit long-term health risks.
When wildfire smoke finally clears, most people assume the danger has passed. The skies look blue again, the air smells normal, and life slowly returns to routine. But according to a new study from UCLAs Fielding School of Public Health, the air inside your home may still be far from safe even weeks after a wildfire is out.
The research found that wildfire smoke can leave behind volatile organic compounds, or VOCs, that continue to seep into indoor air long after outdoor air quality improves. Some of these pollutants are known to be harmful even carcinogenic and in certain cases, indoor pollution levels can actually be higher than whats measured outside during the recovery period. In other words, going back inside doesnt always mean youre breathing cleaner air.
As wildfire seasons grow longer and more intense across the U.S., the findings reveal a major blind spot for homeowners and renters who assume their homes reset once the smoke is gone. ConsumerAffairs spoke with Glory Dolphin Hammes, CEO of air quality company IQAir, to learn more about these health risks and what steps families can take to reduce them.
The risks of poor air quality
What should consumers be most worried about? According to Dolphin Hammes, it comes down to exposure to VOCs days and weeks later.
VOCs like benzene, toluene, ethylbenzene, and xylenes were elevated more in the post-fire period than during active burning, especially in unoccupied homes, showing that residents can be exposed long after visible smoke is gone, she said. This means simply returning home wont automatically eliminate risk.
On top of that, these chemicals can increase consumers health risks long-term.
These VOCs are released from smoke-impacted materials and can continue to off-gas, elevating indoor exposure. Benzene is a known carcinogen, and long-term exposure can increase cancer risk. Toluene and xylene can irritate the eyes, nose, and throat, affect the nervous system, and exacerbate asthma. Ethylbenzene can contribute to respiratory and neurological symptoms. These chemicals are also common in building materials and household products, compounding risk after smoke infiltration.
Reducing chemical exposure
If youve been exposed to these chemicals, Dolphin Hammes encourages consumers to start taking action immediately to limit their health risks. Here are some of her best tips:
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Increase ventilation wisely by opening windows when outdoor air quality improves and outdoor VOCs are lower.
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Run your HVAC system in recirculation with a MERV 13+ filter to avoid drawing outdoor pollution inside.
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Deploy high-performance filtration and activated carbon systems to capture PM2.5, ultrafine particles, and VOCs at high efficiency.
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Clean smoke-soiled surfaces and materials using wet methods (avoid dry sweeping/vacuuming without HEPA filters), and remove or clean fabrics that absorbed smoke.
Continual filtration and cleaning give the biggest reductions in indoor exposures, she explained. When cleaning, avoid using cleaning sprays since nearly all cleaning sprays also release VOCs.
The importance of indoor air quality
Dolphin Hammes explained that indoor air quality is traditionally more polluted than outdoors even in the absence of a wildfire. Because of this, taking steps to filter your air and take the necessary precautions can ensure your family is breathing the cleanest quality air in your home.
Consumers should understand that persisting indoor pollutants arent always detectable by smell, but they can still harm health, she said. Robust filtration tailored to your home size and pollutant mix is more effective than ad-hoc solutions.
Long-term strategies like replacing carpets and upholstery exposed to heavy smoke, cleaning HVAC ducts, and maintaining high-efficiency filters can reduce ongoing emissions. Finally, blended strategies monitoring + filtration + source control + ventilation consistently deliver the greatest health protection. Because indoor air affects every breath you take, post-wildfire indoor air quality deserves the same attention as outdoor air decisions.
Posted: 2026-01-14 17:02:54
