2018年秋冬季长江三角洲区域PM2.5污染来源数值研究

Numerical simulations of PM2.5 pollution source in the Yangtze River Delta region in fall and winter in 2018

使用WRF-Chem和WRF-FLEXPART模式定量研究了2018年秋冬季,尤其是在明显冷空气影响时的长江三角洲PM2.5来源贡献.结果表明:2018年秋冬季长江三角洲以外的跨区域输送对长江三角洲PM2.5的贡献占15.9%,长江三角洲内部排放贡献占84.1%,长江三角洲区域内部排放及污染相互传输的影响比长江三角洲外跨区域输送的影响更为显著.而在冷空气影响时段中,跨区域输送对长江三角洲PM2.5的贡献率为33.1%,约为整个秋冬季长江三角洲外部跨区域平均输送贡献率的2倍,输送影响更为明显;输送对长江三角洲三省一市的贡献为46.2%~56.2%,其中跨区域输送的贡献10.2%~38.6%,也明显大于各自秋冬季的平均水平.在冷空气影响时段,长江三角洲四座重点城市(上海、合肥、南京、杭州)的污染潜在输送路径主要以中东路为主;上海、南京受到长江三角洲以外的污染潜在贡献较多,超过30%;杭州受到长江三角洲以外的污染潜在贡献较少,为16.1%.

This paper used WRF-Chem and WRF-FLEXPART to quantify the source contribution to PM2.5 of the Yangtze River Delta(YRD)region during fall and winter in 2018,especially during the cold air processes.The results showed that the contribution to PM2.5 of the YRD region from inter-regional transport accounted for 15.9%,while the contribution from local emission and intra-regional transport accounted for 84.1%,which indicated that the influence of local emission and intra-regional pollution transport was much more significant than that of inter-regional transport.During cold air processes,the contribution to PM2.5 in the YRD region from intra-regional transport increased to around 33.1%,approximately twice of the average contribution during the whole fall and winter in 2018.The contribution to each provincial region in the YRD region from both intra-and inter-regional transport ranged from 46.2%to 56.2%,among which the inter-regional transport ranged between 10.2%and 38.6%.They were significantly above the averages in the fall and winter.During cold air processes,the potential pollution transport pathways affecting the 4 major cities(Shanghai,Hefei,Nanjing and Hangzhou)was along the“mid-and-east pathway”.The potential pollution contribution from external YRD regions to Shanghai and Nanjing were more than 30%,while that to Hangzhou was smallest at around 16.1%.