AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Estimates of the Annual U.S. Mortality Burden Attributable to Fine Particulate Matter Exposure in Indoor and Outdoor Microenvironments
PARHAM AZIMI, Brent Stephens, Illinois Institute of Technology
Abstract Number: 563 Working Group: Health Related Aerosols
Abstract Elevated ambient concentrations of fine particulate matter (i.e., the mass concentration of particles ≤ 2.5 µm in aerodynamic diameter; PM2.5) have been consistently associated with increased mortality in epidemiology studies. Although epidemiology studies typically use ambient PM2.5 concentrations as surrogates for human exposures, the majority of exposure to PM2.5 in the U.S. and other industrialized nations typically occurs in various other microenvironments, including inside residences, offices, schools, and vehicles. The objective of this work is to estimate the U.S. mortality burden attributable to PM2.5 exposure in various microenvironments in which people spend most of their time. We first modify outdoor air epidemiology concentration-response (C-R) functions and mortality effect estimates from the existing literature to account for estimates of the underlying exposures to ambient PM2.5 in the various microenvironments in which people spend the majority of their time that are likely to have occurred in the original study populations. We then apply these modified ambient-origin C-R function effect estimates to estimates of long-term average PM2.5 concentrations of both indoor and outdoor origin found in various non-smoking microenvironments, including inside residences, indoor environments other than residences (e.g., offices, schools, etc.), vehicles, and outdoors. We use Monte Carlo simulations with 10,000 iterations to sample from distributions of each input parameter to estimate the likely bounds of the mortality burden attributable to exposure to PM2.5 of both indoor and outdoor origin in various microenvironments. Our best estimate of the annual U.S. mortality burden associated with indoor and outdoor PM2.5 exposures across all microenvironments was ~287,000 deaths annually, with an interquartile range (IQR: 25th to 75th percentile) of ~150,000 to ~322,000 deaths annually. Ambient PM2.5 exposures across all microenvironments contributed ~139,000 deaths (IQR: ~90,000 to ~177,000) and indoor PM2.5 exposures contributed ~148,000 deaths (IQR: ~26,000 to ~154,000). The contribution of exposures to PM2.5 of ambient origin in outdoor microenvironments accounted for only ~5% of the total mortality associated with PM2.5, while indoor exposures to PM2.5 of ambient and indoor origin accounted for ~42% and ~52% of the total mortality burden of PM2.5 exposures, respectively.