Air Quality and Health After the 2025 Fires
Conversations After the Fires: Air Quality and Health
Friday, May 2, 2025
Speakers
Haroula Baliaka is a fourth-year Ph.D. candidate in Environmental Science and Engineering at Caltech, working with Professors Paul Wennberg, John Seinfeld, and Rick Flagan. Her research broadly focuses on studying the mysteries behind the elevated particulate levels in Los Angeles, despite decades of air quality regulations. Baliaka is also the student lead for ASCENT, a national monitoring network that measures air pollutants in real time, and PHOENIX, an air quality monitoring network deployed in and around the burned areas of Altadena following the recent Eaton Canyon fire. She holds a Dipl. Ing. in Chemical Engineering from the University of Patras, Greece.
Rima Habre is an Associate Professor of Environmental Health and Spatial Sciences at the University of Southern California (USC). Her work is part of the LA Fire HEALTH Study. Her research aims to understand the effects of complex air pollution mixtures and climate-related exposures on the health of vulnerable populations. She leads the CLIMA (CLIMAte-Related Exposures, Adaptation and Health Equity) Center at USC and co-leads the NEXUS (Network for Exposomics in the U.S.) Center, which aims to advance precision environmental health. Habre received an Sc.D. in environmental health from the Harvard T.H. Chan School of Public Health.
Lea Hildebrandt Ruiz (BS '06) is an Associate Professor at University of Texas at Austin. She studies the formation, transformation, and atmospheric fate of harmful air pollution that kills more than 7 million people per year worldwide. Her laboratory uses state-of-the-science instrumentation in indoor and outdoor environments, as well as mathematical modeling to make better-informed recommendations for environmental policies aimed at improving air quality and human health. Her recent work is part of the LA Fire HEALTH Study.
Sina Hasheminassab is an air quality scientist at NASA Jet Propulsion Laboratory (JPL). His research focuses on integrating advanced monitoring techniques with data-driven methodologies to study air pollution sources, trends, and their societal impacts. He is a co-investigator on NASA's Multi-Angle Imager for Aerosols (MAIA) satellite mission, where he leads its ground-based air quality monitoring subsystem. Hasheminassab holds a Ph.D. in Environmental Engineering from the University of Southern California.
Key Takeaways
Summary of findings presented by Lea Hildebrandt Ruiz
- Particulate matter (PM) and volatile compounds (VOC) were released by the fires in Altadena and the Palisades. Overall, on average, the team observed lower PM levels in the Palisades compared to Altadena.
- Weeks after the fire, outdoor levels of PM are relatively similar inside and outside of the burn zone.
- Indoor levels of PM and some VOCs are higher in damaged homes within the burn area than undamaged homes, which are in turn higher than inside homes outside of the burn area.
- Indoor air filters reduce concentrations of PM and VOCs. HEPA filters are recommended for PM; activated carbon filters for VOCs. A Corsi-Rosenthal box is a cost-effective PM filter: https://engineering.ucdavis.edu/news/science-action-how-build-corsi-rosenthal-box.
Summary of findings presented by Haroula Baliaka and Sina Hasheminassab
- A network of 28 air quality sensors, called PHOENIX, has been deployed throughout Altadena. In addition, a team from JPL has outfitted three of the PHOENIX sites with more sophisticated sensors to better understand what comprises the airborne particulate matter (PM).
- Most days, on average over 24 hours, had low levels of particulate matter in the air, classified as ‘good' by EPA limits. However, concentrations tended to spike into unhealthy levels at certain times of day for up to 60 minutes. This phenomenon potentially is associated with clean-up activities and construction trucks kicking up dust and other particles.
- Prior to the fires, PM levels in LA also rose during dust events, but the dust was made of minerals and not toxic chemicals. The PHOENIX team is currently analyzing samples from the areas around the sensors to determine the makeup of chemicals in the current dust events.
- The JPL-placed sensors show elevated black carbon from traffic at the Woodbury Ave site (a main route for hauling debris from the fires) than at the JPL site, but even the elevated levels are comparable to another monitoring site in Pico Rivera. At the regional scale, the data clearly shows that almost immediately after the fires were put out, air quality levels returned to normal. Overall, based on the data collected so far in and around Altadena, the increased levels of particulate air pollutants are highly localized. The team recommends wearing a mask when you can see dust from trucks and other traffic.
Summary of findings presented by Rima Habre
- The USC Eaton Exposure & Health Community Study, part of the LA Fire HEALTH consortium, is launching a study to understand the health impacts of smoke and ash exposure from the Eaton fire using wearable sensors and exposomics. To participate, please contact [email protected].
- Previous studies show that exposure to contaminants released and traumatic events experienced in urban and wildfires are linked with worsening of respiratory and cardiovascular outcomes like asthma and COPD in the short term; and mental health (depression, PTSD), and cancer outcomes in the long term; and can have negative impacts on pregnancies.
- Studies from the recent Maui fires show exposure to metals such as lead and arsenic and VOCs were more measurable in a subset of people, especially those who went back very early to the burn zone.
- Exposure = very close contact. If you are not breathing in ash or dust or chemicals off-gassing from these, getting it on your skin, or ingesting it (for children), you are not being exposed and put at risk. This is why protection works very well.
- For those participating in or directly next to clean-up activities, P100 masks are recommended.
Watch the video recording above for more context and to hear the speakers' answers to audience-submitted questions.
Related Resources
Air quality monitoring resources:
- PHOENIX (Post-fire airborne Hazard Observation Environmental Network for Integrated Xposure-monitoring)
- ASCENT (Atmospheric Science and Chemistry mEasurement NeTwork)
- South Coast AQMD
- AirNow
Other:
- LA Fire Health Study: Data
- From University of Hawai‘i on Maui fire:
- The environmental and medical geochemistry of potentially hazardous materials produced by disasters (Plumlee et al, 2013)
- Why Indoor Chemistry Matters (National Academies report)
- Los Angeles County Public Health Fire Safety and Health Information
- How Caltech's Real-Time Air Quality Monitor Unraveled Multiple Mysteries
To apply for the Eaton Fire Exposure and Health Community Study: Email [email protected] and follow updates and announcements at https://clima.usc.edu/.