长三角区域大气重污染应急减排效果评估

为评估长三角区域大气重污染应急减排方案的效果，依据上海市环境科学研究院编制的2015年长三角区域高分辨率大气污染源排放清单设计了3级减排方案，利用本地化的WRF-CMAQ模式对长三角区域一次重污染过程进行了模拟验证，并评估了各减排方案的效果.结果显示:①如各城市单独进行减排，在一级、二级和三级减排方案下ρ（PM_2.5）分别降低0~7.2、0~20.6和0.1~34.8 μg/m3，降幅分别为0~11.7%、0~19.5%和0.2%~28.0%，长三角区域空气质量优良率未见明显上升.②如进行区域协同减排，在一级、二级和三级减排方案下ρ（PM_2.5）分别降低0.5~10.0、2.7~30.2和4.3~51.8 μg/m3，降幅分别为1.8%~12.8%、9.3%~23.5%和14.7%~37.0%.对于多数城市，区域协同减排效果比单独减排效果显著，其中舟山市、连云港市和常州市的区域协同减排效果最突出.在三级减排方案下的区域协同减排会使空气质量优良率明显提升，空气质量优良的城市从6个升至10个，中度以上污染城市从12个降至2个.③工业源减排是应急减排的重点，其减排效果可占整体减排效果的50.0%~93.0%.研究显示，要在重污染期间达到较好的减排效果，需要进行区域协同减排，但针对不同城市需要协同进行污染控制的范围具有明显差异，因此，为实现精准管控，未来在开展重污染应急区域协同控制时，需根据实际情况进行协同控制关系的预测. 

Assessment of Emergency Emission Reduction Effect during a Severe Air Pollution Episode in Yangtze River Delta Region

In order to evaluate the effect of severe air pollution emergency emission reduction plans in the Yangtze River Delta (YRD), a three-level emission reduction plan was designed based on a high-resolution air pollution emission inventory in YRD for the year of 2015, which was developed by Shanghai Academy of Environmental Sciences. A severe air pollution episode occurred in YRD was simulated and the effectiveness of the emission reduction plans for this episode was evaluated using the a localized WRF-CMAQ model. The results show that:(1) When each city reduces emissions separately according to the primary, secondary and tertiary emission reduction plans, the ρ(PM_2.5) will be reduced by 0-7.2, 0-20.6 and 0.1-34.8 μg/m3, with change rates of 0-11.7%, 0-19.5% and 0.2%-28.0%, respectively. The excellent rate of regional air quality has not increased significantly. (2) When different cities reduce emissions synergistically, the ρ(PM_2.5) will be reduced by 0.5-10.0, 2.7-30.2 and 4.3-51.8 μg/m3 using the primary, secondary and tertiary emission reduction plans, with rates of 1.8%-12.8%, 9.3%-23.5% and 14.7%-37.0%, respectively. Compared to the emission reduction in individual cities, the regional synergistic emission reductions have much better effects for the control of air pollution in most cities, especially in Zhoushan City, Lianyungang City and Changzhou City. The regional synergistic emission reduction using the tertiary emission reduction plan will significantly increase the excellent rate of regional air quality. The number of cities with excellent air quality will increase from 6 to 10, and the number of cities with pollution above the moderate polluted level will decrease from 12 to 2. (3) Emission reduction of industrial sources is the focus of emergency emission control. The effect of emission reduction of industrial sources can account for 50.0% to 93.0% of the total reduction effect. The results also show that to achieve better emission reduction during severe air pollution episode, regional synergistic emission reduction is needed, but for different cities, the regional synergistic range are significant different. Therefore, in order to achieve precise control in the future, when carrying out regional synergistic emission reduction during severe air pollution emergency, it is necessary to predict the synergistic control relationship according to the actual situation.