Abstract View
Assessing the Impact of Wildfire PM2.5 on Indoor Air Quality with Crowdsourced PurpleAir Sensor Data in California
YUTONG LIANG, Deep Sengupta, Mark Campmier, Joshua S. Apte, Allen Goldstein, University of California, Berkeley
Abstract Number: 290
Working Group: Wildfire Aerosols
Abstract
Driven by fire suppression and climate change, the number and severity of large wildfires have been increasing for decades in western United States. Many studies have connected wildfire smoke exposure to elevated risk of respiratory morbidity. In previous studies, the exposure to wildfire smoke PM2.5 (particles with < 2.5 µm aerodynamic diameter) was typically estimated from ambient (outdoor) concentrations. However, because people in the US on average stay indoors for 87% of the time, the protection against outdoor wildfire smoke particles provided by buildings should not be overlooked in exposure assessments.
The fast-growing PurpleAir sensor network allows us to assess how indoor air quality is moderated by the buildings and occupants’ behavior during wildfire events. Using observations outside and inside over 1400 buildings from the PurpleAir sensor network in California during 2020 and 2018 wildfires, we found that infiltration ratios (indoor PM2.5 of outdoor origin/outdoor PM2.5) were reduced on average by ~50% on smoky days compared with non-smoky days, which was related to reduced ventilation and enhanced indoor filtration. Newer buildings and buildings utilizing air conditioning or filtration had lower infiltration ratios. Even with such protective measures, mean indoor concentration of PM2.5 was on average more than doubled by wildfire events.