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Estimating the Evolving Public Health Impacts of Wildfires in California over the Past Two Decades
ANIKENDER KUMAR, Melissa Venecek, Xin Yu, Yiting Li, Michael Kleeman, University of California, Davis
Abstract Number: 266
Working Group: Health-Related Aerosols
Abstract
Wildfire activity has increased in many parts of the world over the past two decades due to changes in temperature and precipitation patterns associated with global change. Wildfire activity has also increased in California, especially during recent summer months. Wildfires emissions increase concentrations of airborne particulate matter (PM) mass in the region immediately adjacent to the fire and over long transport distances, leading to regionally elevated aerosol loadings. These high PM concentrations from wildfires can have a significant impact on air quality leading to public health impacts including mortality and/or increased severity of COVID-19 illness. As anthropogenic emissions decline in California, increasing wildfire emissions play a larger role in determining the public health impact from air pollution.
In this study, the source-oriented UCD/CIT chemical transport model was used to simulate wildfire PM contributions to PM0.1 and PM2.5 in California for a 17-year period (2000–2016). Gridded anthropogenic emissions were prepared using the raw emissions inventory provided by the California Air Resources Board (CARB). Wildfire emissions were obtained from the Global Fire Emissions Database (GFED). Wildfire contributions to PM0.1 and PM2.5 were compared to contributions from anthropogenic sources using the source-apportionment routines in the UCD/CIT model. Further, the Benefits Mapping and Analysis Program (BenMAP) was used to estimate the number of mortalities from wildfire in California during the study period. Results carried out with 4 km horizontal spatial resolution suggest that wildfires contribute ~10% to total population weighted annual average PM2.5 concentrations, and up to 45% of the acute monthly average PM2.5 concentrations in the recent years over California. The public health impact of past wildfire events and the likely impact of a severe wildfire on the incidence and severity of COVID-19 will be estimated based on the latest epidemiological evidence. The results from this study help to put wildfire emissions in context as an emerging public health threat.