南京市秋季细颗粒物及臭氧生成敏感性初探

为考察江苏省南部地区重点排放源对南京市秋季细颗粒物(PM_(2.5))的贡献率及O_3生成敏感性,采用强力法针对特定排放源及污染物设置不同的排放情景,利用化学传输模拟系统Models-3/Community Multi-scale Air Quality(CMAQ)分析模拟区域内不同情景下地表PM_(2.5)及O_3浓度变化。2012年10月,电厂、钢铁和水泥的污染物排放对南京市PM_(2.5)浓度的平均贡献率分别为6.0%、25.5%和15.9%,对国控站点的贡献率分别为7.2%、17.7%和16.2%。钢铁对下风向区域的地表PM_(2.5)浓度的影响显著高于电厂及水泥部门的排放。从不同情境下模拟O_3地表浓度变化结果看出,南京市城区及下风向区域的O_3浓度随VOC排放削减降低,随NO_x排放削减升高,因而判定南京市秋季O_3生成属于VOC控制区。

Sensitivity Analysis of the Formation of Fine Particle and Ozone in Autumn,Nanjing City

: With the aims at analyzing the contribution of keyemission sources in the south of Jiangsu Province to PM2.5concentration and the sensitivity of ozone formation in autumn in Nanjing City, brute-force method (BFM) is applied to set different emission scenarios for typical sources and pollutants. Chemical transport model of Models-3/ Community Multi-scale Air Quality (CMAQ) is used to simulate the ground concentrations of PM2.5 and ozone in different emission scenarios. In October 2012, the average contributions of power plants, iron & steel and cement plants to PM2.5 in Nanjing are estimated to be 6.0%, 25.5% and 15.9%respectively. Furthermore, the contributions of the three sectors at air quality monitoring sites in Nanjing are calculated as 7.2%, 17.7% and 16.2%. Emissions from the iron & steel plants have a greater influence on the PM2.5 concentrations in the surrounding downwind region. The results from simulating the variation of ground ozone concentrations under different scenarios show that ozone concentrations in the urban areas of Nanjing and the downwind areas reduce with the decrease of VOC emission in the modeling domain, but increase with the decrease of NOx emission. Therefore, the formation of ozone in autumn in Nanjing is in the VOC-limited region.