Lu Shi-Ze, Shi Xu-Rong, Xue Wen-Bo, Lei Yu, Yan Gang
School of Environment, Tsinghua University, Beijing 100084, China.
Center of Air Modeling and Systems Analysis, Chinese Academy for Environmental Planning, Beijing 100012, China.
Huan Jing Ke Xue. 2021 Jul 8;42(7):3099-3106. doi: 10.13227/j.hjkx.202011016.
This study analyzed the impacts of meteorological conditions and changes in air pollutant emissions on PM across the country during the first quarter of 2020 based on the WRF-CMAQ model. Results showed that the variations in meteorological conditions led to a national PM concentration decreased of 1.7% from 2020-01 to 2020-03, whereas it increased by 1.6% in January and decreased by 1.3% and 7.9% in February and March, respectively. The reduction of pollutants emissions led to a decrease of 14.1% in national PM concentration during the first quarter of 2020 and a decrease of 4.0%, 25.7%, and 15.0% in January, February, and March, respectively. Compared to the same period last year, the PM concentration measured in Wuhan City decreased more than in the entire country. This was caused by improved meteorological conditions and a higher reduction of pollutant emissions in Wuhan City. PM in Beijing increased annually before the epidemic outbreak and during the strict control period, mainly due to unfavorable meteorological conditions. However, the decrease in PM in Beijing compared to March 2019 was closely related to the substantial reduction of emissions. The measured PM in the "2+26" cities, the Fenwei Plain and the Yangtze River Delta (YRD) decreased during the first quarter of 2020, with the largest drop occurring in the Yangtze River Delta due to higher YRD emissions reductions. The meteorological conditions of "2+26" cities and Fenwei Plain were unfavorable before the epidemic outbreak and greatly improved during the strict control period, whereas the Yangtze River Delta had the most favorable meteorological conditions in March. The decrease in PM concentration caused by the reduction of pollutant emissions in the three key areas was highest during the strict control period.
本研究基于WRF-CMAQ模型分析了2020年第一季度气象条件和空气污染物排放变化对全国细颗粒物（PM）的影响。结果表明，气象条件变化导致全国PM浓度在2020年1月至2020年3月间下降了1.7%，而1月上升了1.6%，2月和3月分别下降了1.3%和7.9%。污染物排放减少导致2020年第一季度全国PM浓度下降了14.1%，1月、2月和3月分别下降了4.0%、25.7%和15.0%。与去年同期相比，武汉市测得的PM浓度下降幅度大于全国。这是由于武汉市气象条件改善以及污染物排放降幅更大。疫情爆发前及严格管控期间，北京市的PM浓度逐年上升，主要是由于气象条件不利。然而，与2019年3月相比，北京市PM浓度下降与排放大幅减少密切相关。“2+26”城市、汾渭平原和长江三角洲地区（长三角）在2020年第一季度测得的PM浓度下降，其中长三角下降幅度最大，因为长三角地区排放降幅更大。疫情爆发前，“2+26”城市和汾渭平原的气象条件不利，在严格管控期间大幅改善，而长三角地区3月的气象条件最为有利。三个重点区域污染物排放减少导致的PM浓度下降在严格管控期间最高。
