The Los Angeles wildfires in January 2023 were a stark reminder of the urgent need to understand the health impacts of such disasters. As the smoke and ash enveloped the city, residents were left with more questions than answers. But amidst the chaos, a dedicated team of scientists and researchers sprang into action, determined to uncover the hidden dangers lurking in the air. This is their story, and it's a tale of resilience, discovery, and the ongoing quest to protect public health.
The Unseen Dangers of Wildfire Smoke
Wildfire smoke is a known hazard, but the Los Angeles fires presented a unique and extra-dangerous scenario. As UCLA air pollution expert Yifang Zhu observed, it wasn't just trees and plants burning; there was plastic, car batteries, and asbestos tiles, creating a 'toxic soup' of air pollutants. Official air quality monitors recorded high levels of lead and arsenic, but many scientists suspected there were other toxic particles and gases spreading widely, beyond what standard EPA and state monitors tested for.
A Race Against Time: Capturing Samples
Before the fires, Zhu and her team had been preparing to sample the air at Aliso Canyon, where a natural gas leak had caused major health problems in 2015. When the fires broke out, they pivoted, taking their sampling equipment as close to the fires as possible. This opportunity allowed them to 'set the stage' about what was happening during the active fires, providing valuable insights into the composition of the smoke and its potential health risks.
Lingering Risks: Beyond the Smoke
The high benzene levels dissipated after the fires, but other dangerous gases increased later, especially indoors. A few weeks after the fire, health-harming gases like toluene and carbon tetrachloride became more concentrated inside homes. This revealed that homes can absorb dangerous gases, releasing them for days and weeks after the smoke has cleared. People need to be aware that their homes might be contaminated long after the fire is out.
Another research team discovered hexavalent chromium, a cancer-causing contaminant, lingering in the air around cleanup sites. This contaminant can penetrate deep into people's lungs, bodies, and even directly to their brains. The ash also contaminated soil and water, with lead and other heavy metals often remaining high, even after cleanup.
Health Impacts: Unraveling the Mystery
Scientists have known that wildfire smoke exposure leads to respiratory issues, increases the risk of dementia, and affects immune responses. However, the full array of impacts and long-term costs of exposure are still unclear. Research is beginning to uncover some of the health impacts, with data from the emergency room at Cedars-Sinai showing a 24% increase in respiratory issues and a 47% jump in heart attacks in the 90 days following the fires.
Protecting Yourself and Your Family
The biggest questions for ongoing research are about how to protect yourself from similar fires in the future. Clear lessons include wearing an N95 mask or respirator when outside and using air filters indoors, ideally HEPA-rated, to lower indoor pollution. Carbon filters are particularly effective at removing gases. People can also install HEPA filters in their car's air-handling system to keep the air clean while driving.
For those most impacted by the fires, adequate cleanup of soil and buildings is critical. A lack of standardized testing protocols and inconsistent policies from different insurers left many unsure whether their homes were safe to live in again. More coordinated recommendations and rules are needed to help people know whether their homes are safe.
The Way Forward: Learning from the Tragedy
It will take years to get a full picture of the health impacts of the LA fires, but it's crucial to learn from the tragedy. As Harvard environmental health scientist Kari Nadeau says, we need to be able to say, 'OK, in the future, here's what to do to protect your children or protect your elderly community against stroke,' or lung cancer, or the myriad other risks from wildfires that will inevitably come again.
