南京冬季一次重霾污染事件PM2.5区域传输收支分析

利用WRF-Chem模式对2015年12月21—23日南京一次重霾污染过程进行模拟.基于合理的模拟评估,采用大气传输通量计算法,着重分析了此次霾污染过程中模拟的南京地区PM_(2.5)的传输收支特征,以及周边地区大气污染物传输对南京市PM_(2.5)变化的贡献.结果表明,此次霾污染过程中,本地源与外来源区域传输共同影响着南京市的空气质量.PM_(2.5)的跨区域传输是此次重霾污染发生和消亡的重要因素.在霾污染事件的形成维持阶段,南京地区是作为周边地区PM_(2.5)的接收区,大气污染物主要由南京的西边界输入,大气污染物的外源输入是南京PM_(2.5)污染的主要贡献来源,占南京PM_(2.5)污染的84%.在霾污染事件的消亡阶段,南京地区则是作为周边地区PM_(2.5)的源,大气污染物主要由南京的东边界持续向外输出.

Analysis on PM2.5 regional transport and budget of a winter heavy haze pollution event in Nanjing

The WRF-Chem model was used to simulate a process of heavy haze pollution in Nanjing from December 21 to 23, 2015.Based on a reasonable simulation assessment, the transport and budget of PM_2.5 simulated in Nanjing during this process were analyzed by calculating air pollutant transport fluxes to estimate the contribution of air pollutant transport from surrounding regions to the changes of PM_2.5 in Nanjing. The results showed that both local air pollutant emissions and regional transport of external pollution sources jointly affected the air quality of Nanjing in this process of haze. The regional transport of PM_2.5 is an important factor controlling the process of this heavy haze pollution. During the formation and maintenance stages of the haze event, Nanjing is as the receptor area of PM_2.5 from the surrounding regions, and the air pollutants are mainly imported from the west border of Nanjing with the import of air pollutants accounting for 84% of the PM_2.5 pollution in Nanjing. During the disappearance stage of haze event, Nanjing is the source of PM_2.5 emission for the surrounding areas, and air pollutants are mainly exported continuously from the east border of Nanjing.