Fine particulate matter levels and HEPA filtration in Los Angeles homes during a wildland-urban-interface fire.

ABSTRACT: Wildland and wildland-urban-interface (WUI) fires substantially elevate fine particulate matter (PM_2.5) concentrations in surrounding communities. Portable high-efficiency particulate air (HEPA) purifiers are widely recommended to reduce indoor PM_2.5 exposure during such events, yet this guidance largely derives from studies of traffic exhaust, secondhand smoke, or indoor sources, rather than real-world WUI fire episodes. To address this gap, we leveraged data from ongoing randomized crossover trials of long-term use of portable HEPA purifiers in Los Angeles residences. During the Eaton Fire (January 2025), 11 homes were under HEPA intervention and 16 under non-HEPA control. Continuous indoor and outdoor PM_2.5 monitoring before, during, and after the Eaton

SUBMITTER: Chen R 

PROVIDER: S-EPMC12804073 | biostudies-literature | 2026

REPOSITORIES: biostudies-literature