Publications

Xie, YY; Wang, YX; Bilal, M; Dong, WH (2019). Mapping daily PM2.5 at 500 m resolution over Beijing with improved hazy day performance. SCIENCE OF THE TOTAL ENVIRONMENT, 659, 410-418.

Abstract
The application of satellite-derived aerosol optical depth (AOD) to infer surface PM2.5 has significantly increased the spatial coverage and resolutions (1-10 km) of ground-level PM2.5 mapping as required for accurate exposure estimation. The remaining challenge is to further increase the mapping resolution to the sub-km level with improved algorithms to minimize misrepresentation of severe haze as clouds. In this study, we provide the first daily PM2.5 estimation over Beijing at a 500 m resolution using AOD from the Simplified Aerosol Retrieval Algorithm( SARA) and linear mixed effects model. A novel cloud screenmethod is developed which significantly improves data availability during hazy days. The cross-validation R-2 for PM2.5 estimations is 0.82 with the cloud-screened SARA AOD. Based on the satellite-predicted high-resolution PM2.5 map, all-day population-weighted PM2.5 is estimated to be 81.4 mu g m(-3) over Beijing (2.3 times higher than China's NAAQS of 35 mu g m(-3)). Compared to the standard MODIS Dark Target 3 km product which presents a significant percentage of missing data, the 500 m resolution PM2.5 mapping derived from SARA AOD reveals distinct pollution patterns and population exposure conditions during severe hazy days, thereby providing valuable information for pollution control and epidemiological studies. (c) 2018 Elsevier B.V. All rights reserved.

DOI:
10.1016/j.scitotenv.2018.12.365

ISSN:
0048-9697