AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Role of Inter-regional Variability in Aerosol Size Distributions on Respiratory Deposition of PM2.5
JACK KODROS, John Volckens, Shantanu Jathar, Jeffrey R. Pierce, Colorado State University
Abstract Number: 230 Working Group: Regional and Global Air Quality and Climate Modeling
Abstract Many studies have quantified the increased risk of mortality from exposure to PM2.5. The use of total PM2.5 mass as the exposure metric is a noted limitation of this approach, as particle deposition in the respiratory tract is strongly size dependent. Additionally, particle size distributions vary substantially across regions, potentially limiting the ability to apply a single concentration-response function globally. To estimate the fraction of inhaled PM2.5 mass that is deposited in the body, we apply the International Committee on Radiological Protection’s size-resolved deposition model to characteristic ambient aerosol size distributions, measured aerosol size distributions, and simulated aerosol size distributions from a global chemical-transport model with size-resolved aerosol microphysics, GEOS-Chem-TOMAS. For typical size distributions in urban areas, we find that 28% of the inhaled PM2.5 mass is deposited in the respiratory tract, compared to 40% in rural regions and 67% in desert regions. Though, we note that PM composition also has strong variations between these regions. Using simulated annual-average aerosol mass distributions, we perform linear regressions on regions defined in the Global Burden of Disease Study to estimate regional differences between PM2.5 exposure and deposited PM2.5 mass. We find that 20% of mass deposits in Latin America (r2 of 0.86), 65% of mass in Central Europe (r2 of 0.91), and 40% of mass in high-income countries (r2 of 0.61). These results suggest that regional variations in aerosol mass distributions may contribute to differences in the health effects following exposure to PM2.5.