Population Exposure to Ambient PM_2.5 at the Subdistrict Level in China

Abstract

Fine particle pollution is a major public health concern in China. This paper assesses China's potential population exposure to PM_2.5 at the subdistrict level, the smallest census unit with public information. Using both ground-based measurements and satellite-based Aerosol Optical Depth retrievals, we estimate subdistrict-level daily PM_2.5 concentrations by means of the block cokriging approach. Our results reveal that China's population-weighted annual average PM_2.5 concentration during April 08, 2013 and April 07, 2014 is nearly 7 times the annual average level suggested by the World Health Organization (WHO). About 1,322 million people, or 98.6% of China's total population, are exposed to PM_2.5 at levels above WHO's daily guideline for longer than half a year. We also simulate the effects of China's most recent action plan on air pollution control. The simulation results demonstrate that the population exposed to PM_2.5 above China's daily standard for longer than half a year will be reduced by 85% if the plan can achieve its target by 2017. Nevertheless, PM_2.5 will be still at a harmful level to public health, which calls for additional effort in pollution control.

Keywords: PM2.5, population exposure, MODIS AOD, China.

JEL Classification: Q53, I19