Global and Regional Simulations of EPFR Concentrations From Biomass Burning and Anthropogenic Sources Using GEOS-Chem and Their Contribution to ROS Production in the Lung Lining Fluid

MEREDITH SCHERVISH, Pascale Lakey, Regina Luu, Manabu Shiraiwa, University of California, Irvine

     Abstract Number: 128
     Working Group: Chemicals of Emerging Concern in Indoor and Outdoor Aerosol: Sources, Vectors, Reactivity, and Impacts

Abstract
Environmentally persistent free radicals (EPFRs) in PM have received growing attention for their potential toxicity as they are redox active to form reactive oxygen species (ROS). EPFRs are formed from incomplete combustion, including biomass burning and vehicle exhaust. Their long atmospheric lifetime implies that, in addition to local sources, long-range transport may impact local concentrations of EPFRs. Measurements of EPFRs in PM have been conducted across the globe with concentrations ranging from 10¹⁶-10²⁰ spins/g of PM and have been shown to vary with different emissions sources as well as meteorological conditions. In this work, we estimate EPFR concentrations across the globe using regional and global simulations of black carbon from GEOS-Chem. We utilize tight correlations between emission markers of biomass burning and vehicles and EPFR content in particulate matter. We reproduce measurements of EPFRs around the globe reasonably well and find that anthropogenic sources consistently contribute more to total EPFR concentrations in the investigated regions. Equivalent cigarettes smoked based on simulated EPFR concentrations reach up to 3.5 per day in the most polluted areas in China, while major cities in the US and Europe reach up to 0.75 per day. EPFR, iron, copper, and PM_2.5 concentrations are then used as inputs to the KM-SUB-ELF model to predict the production rates of ROS in the epithelial lining fluid (ELF). We find that the OH radical production from EPFR is similar in magnitude to the production from biogenic SOA suggesting that anthropogenic EPFRs contribute significantly to the health effects of PM.