Wildfires that affected Los Angeles, impacting approximately 20 million people, led to concerns about toxic smoke, contaminated soil, and poisoned water. Scientists from various institutions initiated research to understand the short-term and long-term health effects, forming a consortium of 10 research institutions.
Smoke Composition and Lingering Pollutants
Initial analyses indicated that the smoke from the Palisades and Eaton fires was particularly hazardous due to the burning of not only natural vegetation but also materials from houses, such as plastics, car batteries, and asbestos tiles. Official air quality monitors registered elevated levels of lead and arsenic, even miles from the fire sites. Researchers also suspected other toxic particles and gases were present that standard monitors did not detect.
UCLA air pollution experts deployed equipment to sample air during and after the fires. High levels of benzene, a carcinogen, were measured outdoors while fires were active. After the fires ceased, outdoor benzene levels decreased, but other hazardous gases like toluene and carbon tetrachloride increased inside homes weeks later. This suggests homes can absorb and re-release dangerous gases from drywall, furniture, and other materials.
Another research team identified hexavalent chromium, a carcinogen, in the air around cleanup sites long after the fires. This contaminant was found in nanoparticles capable of deep penetration into the lungs and other organs. Ash also contaminated homes, soil, and water, with lead and other heavy metal levels often remaining high in homes and soil even after initial cleanup efforts.
Health Impacts Identified
Exposure to wildfire smoke is known to be linked to respiratory problems (e.g., asthma, COPD), cardiovascular issues, and dementia. Studies on urban wildfire smoke, particularly from fires involving varied materials, are less common.
Research using data from the Cedars-Sinai emergency room, close to the Palisades fire, revealed significant health impacts in the 90 days following the fires:
- A 24% increase in respiratory issues.
- A 47% increase in heart attacks.
- Over a 100% increase in abnormal blood tests, including unexpected blood sugar readings, disrupted immune system indicators, and altered metabolic profiles. These suggest body-wide stress impacting multiple organ systems.
Longer-term health problems, including heart issues and mental health stress, are anticipated. Ongoing research includes a UCLA-led study tracking health changes in over 4,000 individuals and studies focusing on firefighters and first responders, and individuals who experienced high smoke doses fighting fires at their homes.
Protection Measures and Future Preparedness
Recommendations for protection from future fires include:
- Wearing N95 masks or respirators outdoors to prevent smoke inhalation.
- Using HEPA-rated and carbon filters indoors and in car air-handling systems to purify air.
- Thoroughly cleaning dust and ash inside living spaces.
- Considering low-cost air monitors for indoor air quality.
There is a critical need for adequate cleanup of contaminated soil and buildings, with a reported lack of standardized testing protocols and coordinated guidance post-fires. Funding for some key long-term studies remains uncertain, with private philanthropy filling gaps left by shifts in federal research funding priorities. Researchers emphasize the importance of learning from these events to better protect communities from future wildfires.