南京环境空气质量特征及变化分析

Spatial-temporal characteristics of ambient air quality in Nanjing

基于2015年1月1日—2021年2月10日南京市大气污染物监测数据,分析了南京市主要大气污染物时空分布特征与潜在源区贡献.结果表明:1)近6年南京市6种大气污染物(CO、NO_(2)、SO_(2)、O_(3)、PM_(10)和PM_(2.5))年均质量浓度分别为800、43.1、13.0、106.0、77.1和43.0μg·m^(-3);南京臭氧质量浓度均值高于中国典型城市(北京、上海、广州、成都、兰州和武汉),而PM_(2.5)平均质量浓度最低.2)2015—2020年南京NO_(2)、PM_(10)和PM_(2.5)超标天数呈减少趋势,平均降低率分别为29.1%、38.1%和28.1%,而臭氧超标天数呈增加趋势;臭氧季节变化表现出夏高冬低,其他5种污染物均呈现冬季高特征.3)冬季(特别是1月)南京PM_(2.5)质量浓度均值最高,对该时间段南京细颗粒物进行潜在源分析,发现南京地区细颗粒物主要受周边工业污染物输送影响,安徽、江苏北部和山东为主要潜在源区.4)对比研究了2019、2020和2021年1—2月大气污染物情况,发现2020年南京大气污染物质量浓度最低,说明因新冠疫情采取的封控措施减少了人类活动,进而显著影响了环境空气质量.

Based on monitoring data of atmospheric pollutants in Nanjing from Jan.1,2015 to Feb.10,2021,the spatial-temporal distribution characteristics of Nanjing s ambient air quality and the contribution of potential source areas were analyzed.The average concentrations of six air pollutants(CO,NO_(2),SO_(2),O_(3),PM_(10),and PM_(2.5))were 800μg·m^(-3),43.1μg·m^(-3),13.0μg·m^(-3),106.0μg•m^(-3),77.1μg·m^(-3),and 43.0μg·m^(-3),respectively.The average concentration of ozone in Nanjing was higher than that in China s other typical cities(Beijing,Shanghai,Guangzhou,Chengdu,Lanzhou,and Wuhan).The number of pollution days for NO_(2),PM_(10),and PM_(2.5) were reduced by 29.1%,38.1%,and 28.1%during 2015 to 2020.However,the frequency of ozone pollution days was increasing(the highest value in summer and the lowest value in winter).The potential source analysis of fine particulate matter in January of 2015-2020 was carried out.It was found that the potential source for Nanjing s PM_(2.5) was surrounding industrial areas(Anhui province,north of Jiangsu province,and Shandong province).The concentration of air pollutants in Nanjing in 2020 was lower than that in 2019 and 2021.It indicated that the reduction of human activity caused by COVID-19 pandemic has resulted in less air pollutant emissions and improved air quality in Nanjing.