关中地区冬季人为源减排对PM_(2.5)浓度的影响

Response of the wintertime PM_(2.5) level to anthropogenic emission mitigations in the Guanzhong basin

使用WRF-Chem模式和关中地区高分辨率的人为源排放清单,选取2013年冬季不利于关中地区污染物扩散的4类典型天气形势中的各1d,模拟了PM_(2.5)时空分布和日变化趋势,同时以国家环境空气质量标准为目标,制定人为源等比例减排的敏感性试验.结果表明,模式可以较好地捕捉PM_(2.5)的时空分布和变化趋势,且与天气形势有着一致的对应关系.在4类不利天气形势下,PM_(2.5)浓度随着人为排放源的减少呈二次曲线下降趋势,PM_(2.5)浓度下降率与所在区域原有大气污染程度成正比.在不同天气形势下,要使PM_(2.5)浓度达到国家环境空气质量标准75mg/m^3时,人为源需削减比例为30%~60%.

Based on the analysis of four typical unfavorable synoptic situations during wintertime in the Guanzhong basin(GZB),the WRF-Chem model had been applied to simulate the selected four days representing the four unfavorable synoptic situations during the wintertime of2013.The results generally showed good consistence between the modeled and observed PM2.5distributions and variations.Further studies had been performed to verify the PM2.5response to the anthropogenic emission mitigation under the four unfavorable synoptic situations in GZB.Sensitivity results demonstrated that the mass concentration of PM2.5decreases nonlinearly along with the anthropogenic emission mitigation.Additionally,the PM2.5mitigation was more significant at the more polluted areas.The anthropogenic emission in GZB needed to be reduced30%~60%to meet the China National Air Quality Standard under the above-mentioned four unfavorable synoptic situations.