RAPID: Rapid Assessment of Air Quality During Wildland-Urban Interface Fires in Southern California

This RAPID project focuses on the nature of smoke and ash pollution from the fires occurring at the wildland-urban interface (WUI) in the Los Angeles region. The goals this effort are to sample and speciate air pollutants emitted from the fires and quantify the contribution of structure fires to concentrations and impacts of hazardous air pollutants in the densely populated megacity of Los Angeles.

The knowledge gained from this work will inform disaster response policy (risk assessment, hazard control), ecosystem health risks, prediction of human health risks, and recovery efforts in the wake of a growing national hazard: catastrophic urban fires.

The presence of advanced polymer materials (e.g., in carpets, flooring, clothing, appliances, housewares) and metals (e.g., in electronics, appliances, vehicles, fasteners) suggests that the content of urban fire emissions should be complex and potentially more toxic than emissions from traditional biomass burning events. Analysis of field data suggest that structure fires in WUI regions might produce severe exposure to polycyclic aromatic hydrocarbons (PAHs), halogenated compounds (e.g., PFAS), dioxins, furans, and transition metals, orders of magnitude larger than the exposure from wildfire emissions.

Working with leadership and staff at the South Coast Air Quality Management District (SCAQMD), the proposal team has deployed a small network of AirPen and UPAS systems at existing air quality monitoring stations as close as possible to the existing fires in the northern Los Angeles region. This air quality sampling is expected to last for four weeks but may be adjusted to include additional sites or sampling equipment in the future depending on the nature of the fires.

Other region-specific data streams: criteria pollutants measured at SCAQMD air quality monitoring stations, fire activity, and remote sensing (e.g., satellite) and weather (e.g., reanalysis, back trajectory) data will supplement the interpretation of the chemical data.

Ash is expected to persist in the region for weeks-to-months following this event and ash samples will be collected from within the burn areas and from fugitive emission events (i.e., windblown dust) and analyzed. The ash samples are likely to contain a different mixture of toxic species (relative to the smoke), and ash exposure will remain a major human and environmental hazard for first responders, cleanup crews, homeowners, and members of the surrounding community.

This effort will demonstrate how structure fires and specific structural fuels have the potential to modulate the environmental and health impacts from WUI fires. Training for both a graduate student and a postdoctoral scholar will be supported through the project.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.