Optimization of a NO x and VOC Cooperative Control Strategy Based on Clean Air Benefits.

Serious ambient PM 2.5 and O 3 pollution is one of the most important environmental challenges of China, necessitating an urgent cost-effective cocontrol strategy. Herein, we introduced a novel integrated assessment system to optimize a NO x and volatile organic compound (VOC) control strategy for the synergistic reduction of ambient PM 2.5 and O 3 pollution. Focusing on the Beijing-Tianjin-Hebei cities and their surrounding regions, which are experiencing the most serious PM 2.5 and O 3 pollution in China, we found that NO x emission reduction (64-81%) is essential to attain the air quality standard no matter how much VOC emission is reduced. However, the synergistic VOC control is strongly recommended considering its substantially human health and crop production benefits, which are estimated up to 163 (PM 2.5 -related) and 101 (O 3 -related) billion CHY during the reduction of considerable emissions. Notably, such benefits will be greatly reduced if the synergistic VOC reduction is delayed. This study also highlights the necessity of simultaneous VOC and NO x emission control in winter while enhancing the NO x control in the summer, which is contrary to the current control strategy adopted in China. These findings point out the right pathways for future policy making on comitigating PM 2.5 and O 3 pollution in China and other countries.