2015-2023年和田市大气污染特征及主导污染物的潜在来源

Characteristics of air pollution and potential sources of dominant pollutants in Hotan City from 2015 to 2023

位于塔里木盆地南缘的和田市是我国大气污染最严重的城市之一,为了探究和田市大气污染特征及其潜在来源,基于2015—2023年和田市环境空气质量AQI数据与主要污染物PM_(2.5)、PM10、CO、NO_(2)、SO_(2)、O_(3)的质量浓度数据分析了研究期间和田市的空气质量状况与主要污染物的污染特征,接着计算并推导出了影响和田市空气质量状况的主导污染物,最后利用后向轨迹模式和潜在源贡献因子法探究了不同季节主导污染物的潜在源分布及其贡献水平.结果表明:2015—2023年和田市大气污染形势严峻,9 a的AQI平均值为199.45,属于中度污染水平,9 a中优良率仅为23.8%,而污染率达到了76.2%,其中2022年污染最为严重,AQI平均值为220.60,达到了重度污染水平.污染物PM_(2.5)、PM10、O_(3)、NO_(2)、SO_(2)和CO的平均浓度值分别为103.43、340.24、86.72、25.31、27.26μg·m^(-3)和1.15 mg·m-3,其中PM_(2.5)与PM10浓度值分别为国家年均二级浓度限值(35和70μg·m^(-3))的2.9倍和4.8倍,污染最为严重.PM10为影响和田市空气质量的主导污染物,四季的平均比重值高达0.97,而污染物PM_(2.5)、O_(3)、NO_(2)、SO_(2)和CO平均比重值之和仅为0.03,影响有限.和田市大气污染的四季重点贡献源区为塔里木盆地,次要贡献源区为中亚地区.

Hotan,situated at the southern perimeter of the Tarim Basin,stands amongst the most drastically polluted cities in China.This research undertakes an analytical review of the atmospheric pollution characteristics and possible sources in Hotan.It relies on AQI data concerning the city’s air quality conditions and the mass proportion information of prevalent contaminants such as PM_(2.5),PM10,CO,NO_(2),SO_(2),and O_(3),spanning from 2015 to 2023.Insight into dominant pollutants affecting the air quality in Hotan is derived through calculations,followed by discerning potential pollutant origins and assessing their seasonal contribution levels using the backward trajectory model and potential source contribution factor technique.Findings reveal a grim picture of Hotan’s air pollution severity from 2015—2023,with an average AQI of 199.45,signifying moderate pollution.The quality satisfaction rate remained at 23.8%during this period,whereas pollution escalated to a staggering 76.2%,with 2022 bearing the brunt,exhibiting an average AQI of 220.60,denoting heavy pollution.Concentration averages for pollutants PM_(2.5),PM10,O_(3),NO_(2),SO_(2),and CO were 103.43,340.24,86.72,25.31,27.26μg·m^(-3),and 1.15 mg·m-3 respectively,where in PM_(2.5)and PM10 levels crossed the national annual secondary concentration threshold of 35 and 70μg·m^(-3),2.9 and 4.8 times respectively.PM10 was discerned to be the principal pollutant,whose seasonal weight average was 0.97,while the collective weight average of other pollutants remained a nominal 0.03,exerting minimal influence.Lastly,it is established that Tarim Basin acts as the highest contributing source area for Hotan’s air pollution,followed by Central Asia.