基于数值模拟对西安地区冬季一次重污染过程PM2.5区域来源解析

西安是关中盆地经济发展的核心城市，特殊的地形和工业发展导致冬季细颗粒物（PM_2.5）污染严重，制定科学合理的治理措施迫切需要明确PM_2.5的来源.本文基于空气质量模式CAMx（Comprehensive Air Quality Model with extensions）、颗粒物源解析模块PSAT（Particulate Source Apportionment Technology）及融入多种来源数据后建立的排放清单来量化西安地区本地及区域传输贡献.在本文研究的重污染过程中，模式的模拟精度合理，模拟与观测值相关系数为0.78，FAC2达到95%.PSAT模块在本次重污染过程中对西安PM_2.5的来源解析结果显示：在城区，西安本地为最大的排放源区，日均贡献率均大于60%，其次为咸阳8%，省外的传输为6%；在郊区，西安本地的贡献减少，传输贡献增加，其中阎良区传输贡献达到83%.对西安城区的一次细颗粒物面源排放量减少50%模拟后，城区和郊区来自周边区域渭南或咸阳的贡献率有6%~8%的增长.该研究结果表明需要从本地排放管控和区域联防两方面来改善西安地区的空气质量.

An analysis of PM2.5 regional sources from heavy pollution in the winter of Xi'an based on numerical simulation

Xi''an is the core city of the economic development of the Guanzhong Basin. The special topography and industrial development had led to the serious pollution of PM_2.5 in winter there. It is urgently required to determine the source of PM_2.5 so as to formulate scientific and reasonable control measures. This paper quantifies the local and regional transmission contribution of Xi''an, based on the CAMx (Comprehensive Air Quality Model with extensions), PSAT (Particle Source Application Technology) and emission list established after incorporating multiple source data. In the process of heavy pollution research, it is shown that the simulation accuracy of the model is reasonable, the correlation coefficient between the simulation and observation is 0.78, and the FAC2 reaches 95%. The PSAT module''s analysis of the source of Xi''an PM_2.5 in the process of heavy pollution reveals that, in the urban area, Xi''an is the largest source area, where the average daily contribution rate is greater than 60%. This is followed by Xianyang at 8%, and transmission outside the province is 6%. In the suburbs, Xi''an local contribution decreases, transmission contribution increases, and transmission contribution of Yanliang District reaches 83%. After simulating the emission reduction of fine particles in Xi''an''s urban area by 50%, the contribution rate of urban and suburban areas from Weinan and Xianyang in the surrounding area increased by approximately 6%~8%.The results of the study indicate that the air quality in Xi''an must improve in terms of both local emissions control and regional joint defense.