Assessing PM2.5 emissions in 2020: The impacts of integrated emission control policies in China

Problems with PM2.5 pollution in the Pearl River Delta (PRD) have been significantly reduced since the Chinese government released a series of emission control policies including the strengthened controls in the 13(th) Five-Year Plan. This study assessed the efficacy of emission control measures using the Community Multiscale Air Quality (CMAQ) model to provide data-driven support to government decision making, which is becoming increasingly important. This study aimed to quantitatively evaluate the integrated results of proposed policies for controlling PM2.5 concentrations. Accordingly, the regional 2015 emission inventory was modified with recently released government data for the PRD, and scenarios for four dynamical emission-reduction policies (S1-S4) were explored. The results show that all four proposed control measures can help to reduce PM2.5 concentrations throughout Hong Kong (HK), Macao, and the PRD economic zone (PRD EZ) by 2020. In all cases, reductions in PM2.5 concentrations were larger over PRD EZ than over HK. For HK, the predicted annual concentrations of PM2.5 were less than 20 mug/m(3) for S1-S3 and less than 15 mug/m(3) for S4. For Macao, the predicted annual concentrations of PM2.5 were less than 25 mug/m(3) for S1 and less than 15 mug/m(3) up to S3. Regionally, HK had the lowest PM2.5 levels, and the area around Foshan had the highest. Controlling the sources of air pollution (i.e., industry, transport, power production, and other sources) within PRD can get most of the PRD EZ region to below 35 mug/m(3). Similar national air quality management efforts could reduce PM2.5 levels to less than 25 mug/m(3) in the PRD EZ and less than 15 mug/m(3) in HK. Control measures in S1 led to significant improvement in Shenzhen and HK, but the S3 option brought the greatest improvement for PRD EZ and Macao. The S4 policy option led to substantial reductions, particularly for HK.