Articles | Volume 17, issue 16
Research article
29 Aug 2017
Research article |  | 29 Aug 2017

Projected changes in haze pollution potential in China: an ensemble of regional climate model simulations

Zhenyu Han, Botao Zhou, Ying Xu, Jia Wu, and Ying Shi

Abstract. Based on the dynamic downscaling by the regional climate model RegCM4 from three CMIP5 global models under the historical and the RCP4.5 simulations, this article evaluated the performance of the RegCM4 downscaling simulations on the air environment carrying capacity (AEC) and weak ventilation days (WVDs) in China, which are applied to measure haze pollution potential. Their changes during the middle and the end of the 21st century were also projected. The evaluations show that the RegCM4 downscaling simulations can generally capture the observed features of the AEC and WVD distributions over the period 1986–2005. The projections indicate that the annual AEC tends to decrease and the annual WVDs tend to increase over almost the whole country except central China, concurrent with greater change by the late 21st century than by the middle of the 21st century. It suggests that annual haze pollution potential would be enlarged under the RCP4.5 scenario compared to the present. For seasonal change in the four main economic zones of China, it is projected consistently that there would be a higher probability of haze pollution risk over the Beijing–Tianjin–Hebei (BTH) region and the Yangtze River Delta (YRD) region in winter and over the Pearl River Delta (PRD) region in spring and summer in the context of the warming scenario. Over Northeast China (NEC), future climate change might reduce the AEC or increase the WVDs throughout the whole year, which favours the occurrence of haze pollution and thus the haze pollution risk would be aggravated. The relative contribution of different components related to the AEC change further indicates that changes in the boundary layer depth and the wind speed play leading roles in the AEC change over the BTH and NEC regions. In addition to those two factors, the precipitation change also exerts important impacts on the AEC change over the YRD and PRD zones.

Short summary
Based on the future projection of high-resolution regional climate simulations under the medium-low radiative forcing scenario, the haze pollution potential tends to increase almost over the whole of China except central China, and this increase would be generally aggravated over time. There would be a higher probability of pollution risk over Beijing–Tianjin–Hebei and Yangtze River Delta in winter, over Pearl River Delta in spring and summer, and over Northeast China throughout the whole year.
Final-revised paper