Anthropogenic fine particulate matter pollution will be exacerbated in eastern China due to 21st century GHG warming

Abstract

Abstract. China has experienced a substantial increase in severe haze events over the past several decades, which is primarily attributed to the increased pollutant emissions caused by its rapid economic development. The climate changes observed under the warming scenarios, especially those induced by increases in greenhouse gases (GHGs), are also conducive to the increase in air pollution. However, how the air pollution changes in response to the GHG warming has not been thoroughly elucidated to date. We investigate this change using the century-long large ensemble simulations with the Community Earth System Model 1 (CESM1) with the fixed anthropogenic emissions at the year 2005. Our results show that although the aerosol emission is assumed to be a constant throughout the experiment, anthropogenic air pollution presents positive responses to the GHG-induced warming. The anthropogenic PM2.5 concentration is estimated to increase averaged over eastern China at the end of this century, but varying from regions, with an increase over northwestern part of eastern China and a decrease over southeastern part. Similar changes can be observed for the light air pollution days. However, the severe air pollution days are reported to increase across eastern China at the end of this century, particularly around the Jing–Jin–Ji region. Further research indicates that the increased stagnation days and the decreased light precipitation days are the possible causes of the increase in PM2.5 concentration, as well as the anthropogenic air pollution days. Estimation shows that the effect of climate change induced by the GHG warming can account for 11 %–28 % of the changes in anthropogenic air pollution days over eastern China. Therefore, in the future, more stringent regulations on regional air pollution emissions are needed to balance the effect from climate change.