Using Low-Cost Sensor Networks To Estimate Health Impacts of Indoor Exposures to Wildfire Emissions

ELLIOTT GALL, Ruth Dittrich, Julia Weinand, Franklyn Santos, Joshua Zulueta, Portland State University

     Abstract Number: 230
     Working Group: Biomass Combustion: Outdoor/Indoor Transport and Indoor Air Quality

Abstract
Wildfires are increasing in frequency and intensity and are a substantial source of ambient PM_2.5. Because populations are advised to stay indoors when outdoor air quality is degraded by a wildfire, indoor environments can be a major determinant of exposure to products of biomass combustion. In this study, we collect measurements of indoor and outdoor PM_2.5 levels from an adventitiously deployed low-cost sensor network (PurpleAir) in the Portland, OR, USA metropolitan area during the Labor Day fires of September 2020. We develop a time and location specific PM_2.5 correction factor using linear regression between outdoor PurpleAir monitors and identified, nearby reference monitors operated by the Oregon Department of Environmental Quality. We identified 14 PurpleAir sensors in the metropolitan region identified as deployed indoors during the period of elevated outdoor PM_2.5 due to wildfires; we estimate PM_2.5 concentrations in these indoor spaces by applying the correction determined from outdoor sensors and reference stations. Infiltration factors are estimated by partitioning the time-series indoor and outdoor PM_2.5 data for analysis during periods when indoor sources are expected to be minimal. Infiltration factors of PM_2.5 and measured PM_2.5 concentrations will be used as inputs into a model (BenMAP-CE) to estimate the health costs of wildfire PM exposure, including exploration of the impact of building infiltration factor on health outcomes due to exposure to wildfire associated PM_2.5.