Wednesday, 10 January 2018: 2:15 PM
Salon G (Hilton) (Austin, Texas)
Research efforts to better characterize the differential toxicity of PM2.5 speciation are often hindered by the sparse or non-existent coverage of ground monitors. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA’s Terra satellite is the only satellite aerosol product providing information of aerosol shape, size and extinction globally that can be used to estimate PM2.5 speciation concentrations. In the past, MISR only provides a 17.6 km product, a bit too coarse for air pollution health effects research and to capture local spatial variability of PM2.5 speciation. In this study, generalized additive models (GAMs) were developed using MISR prototype 4.4 km-resolution aerosol data with meteorological variables and geographical indicators, to predict ground-level concentrations of PM2.5 sulfate, nitrite, organic carbon (OC) and elemental carbon (EC) in Southern California between 2001 and 2015. The GAMs are able to explain 66%, 62%, 55% and 58% of the daily variability in PM2.5 sulfate, nitrate, OC and EC concentrations, respectively. Predicted concentrations capture large regional patterns as well as fine gradients of the four PM2.5 species in urban areas of Los Angeles and other counties, as well as in the Central Valley. This study is the first attempt to use MISR prototype 4.4 km-resolution fractional AODs data to predict PM2.5 sulfate, nitrate, OC and EC concentrations at the sub-regional scale. Our analysis suggests that the MISR 4.4 km fractional AODs provide a promising way to capture hotspots of PM2.5 speciation, understand the effectiveness of air quality controls, and allow our estimated PM2.5 speciation data to be linked with common spatial units such as census tract or zip code in epidemiological studies.
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