研究报告
尉鹏,李娟,赵森,靳文静,胡荣明,曹军骥,胡京南.西安市“阶梯型”持续污染过程演变及PM2.5区域输送分析[J].环境科学学报,2022,42(2):298-307
西安市“阶梯型”持续污染过程演变及PM2.5区域输送分析
- Analysis of the evolution of the "stepped" continuous pollution process and the regional transport of PM2.5 in Xi'an
- 基金项目：国家重点研发计划项目（No.2017YFC0212202）
- 作者
- 单位
- 尉鹏
- 中国环境科学研究院， 北京 100012
- 李娟
- 中国环境科学研究院， 北京 100012;西安科技大学测绘科学与技术学院， 西安 710054
- 赵森
- 合肥市气象局，合肥 230041
- 靳文静
- 中国环境科学研究院， 北京 100012
- 胡荣明
- 西安科技大学测绘科学与技术学院， 西安 710054
- 曹军骥
- 中国科学院地球环境研究所，西安 710061
- 胡京南
- 中国环境科学研究院， 北京 100012
- 摘要：为探究2016年11月西安市阶梯型持续污染过程的动态演变规律，利用NCEP再分析数据分析了2016年11月7日—22日的天气形势演变过程，结合CAMx-PSAT模型及化学组分在线监测数据，分析了“阶梯型”演变过程中的区域输送以及大气颗粒物的化学组分变化.结果表明：①由于西安市特殊的盆地地形因素及独特的天气形势变化，导致本次“阶梯型”污染过程出现“谷-峰-峰-峰-谷”的时序变化特征，3个上升阶段的天气形势演变主要为“高压脊-内蒙古低压东移-鞍形场”；②“阶梯型”演变过程中，主要有3条PM2.5输送通道：偏东北输送、偏北输送以及偏东输送，其中偏东北输送来自渭南、运城、洛阳、临汾、吕梁、晋中，约占输送总量的45%；偏北输送主要为本地积累及咸阳输送，约占总输送量的90%；偏东输送的主要城市为渭南、运城、洛阳及其他地区，输送占比最高上升至70%左右；③3个上升阶段污染物浓度峰值期间，二次无机盐（sulfate-nitrate-ammonium， SNA）分别占PM2.5的50%、41%、52%，其中第三上升阶段中污染物的二次转化最为强烈.研究表明，西安市“阶梯型”污染演变是由于独特的地形加之天气形势变化引起的，“阶梯型”污染过程中的区域输送及化学组分也呈现不同的变化规律.
- Abstract：In order to explore the dynamic evolution of the step-type continuous pollution process in Xi'an during November 2016， the NCEP reanalysis data was used to analyze the evolution of the weather situation from November 7th to 22nd， 2016. The regional transport and the changes of the chemical composition of atmospheric particles during the evolution of the "stepped" are analyzed by combining the CAMx-PSAT model and the online monitoring data of chemical composition. The results suggest that： ①Due to the special basin topographical factors and unique weather situation changes in Xi’an， the characteristic of the "stepped" pollution process has been "valley-peak-peak-peak-valley" time-series changes. The three rising stages thereof with the evolution of the weather situation is mainly "high-pressure ridge-Inner Mongolia low-pressure moved eastward-saddle field". ②In the process of " stepped " evolution， there are three main transportation channels of PM2.5： northeast transport， north transport， and east transport. The northeast transport comes from Weinan， Yuncheng， Luoyang， Linfen， Luliang， and Jinzhong accounting for about 45%. The northerly transport is mainly local accumulation and Xianyang transport， accounting for about 90% of PM2.5. To the east transport， the main cities are Weinan， Yuncheng， Luoyang and other regions， peaking at around 70%. ③ During the period of peak pollutant concentration in the three rising stages， the secondary inorganic salt SNA accounted for 50%， 41%， and 52% of PM2.5， respectively， wherein the second conversion of pollutants was the most intense in the third rising stage. Studies have shown that the evolution of the " stepped " pollution in Xi'an is caused by both the unique topography and changes in weather conditions. There are different variation rules for regional transport and chemical composition of the "stepped" pollution process as well.
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