旷雅琼,邹忠,张秀英,常运华.长三角地区大气污染物对新冠肺炎封城的时空响应特征[J].环境科学学报,2021,41(4):1165-1172
长三角地区大气污染物对新冠肺炎封城的时空响应特征
- Spatial-temporal responses of atmospheric pollutants to the COVID-19 lockdown across the Yangtze River Delta region
- 基金项目：国家自然科学基金（No.41975166，41705100）；环境模拟与污染控制国家重点联合实验室专项经费（No.19K01ESPCT）；上海市大气颗粒物污染防治重点实验室开放课题（No.FDLAP19001）
- 旷雅琼
- 1. 南京信息工程大学应用气象学院, 耶鲁大学-南京信息工程大学大气环境中心, 南京 210044;2. 复旦大学环境科学与工程系, 上海市大气颗粒物污染防治重点实验室, 上海 200433
- 邹忠
- 复旦大学环境科学与工程系, 上海市大气颗粒物污染防治重点实验室, 上海 200433
- 张秀英
- 南京大学国际地球系统科学研究所, 南京 210093
- 常运华
- 1. 南京信息工程大学应用气象学院, 耶鲁大学-南京信息工程大学大气环境中心, 南京 210044;2. 复旦大学环境科学与工程系, 上海市大气颗粒物污染防治重点实验室, 上海 200433
- 摘要：利用2020年1月1日—2月29日上海、南京、合肥和杭州4个城市常规污染物的逐时监测资料，结合卫星反演的NO2垂直柱浓度信息，探讨了新冠肺炎封城的前、中、后期长三角地区城市大气污染物的污染水平及响应特征.结果显示：除O3外，其余大气污染物的平均浓度在时间上的整体变化趋势均表现为封城前>封城中（1月24日—2月10日）>封城后，表明空气质量并非完全受封城导致的污染减排控制.封城期间的PM2.5/PM10比值高于封城前和封城后，表明气溶胶二次生成对封城期间仍出现的颗粒物污染可能有重要贡献.Ox浓度在封城期间也有显著上升（p<0.01），表明大气氧化性可能在NO2减少的背景下得到强化，从而促进二次气溶胶的生成.从空间看，O3分布呈以城市为中心的包围式往内聚集分布，表明以局地生成为主.PM2.5、PM10、CO、SO2和NO2分布特征为北高南低，表明冬季自北向南的区域传输对封城期间的空气污染有重要贡献.卫星反演结果进一步证实华北平原是污染的主要源区，这也得到轨迹来源分析的佐证.
- Abstract：From January 1 to February 29, 2020, using hourly monitoring data of criteria pollutants in Shanghai, Nanjing, Hefei and Hangzhou, combined with the vertical columns of SO2 and NO2 from satellite inversions, we explore the pollution levels and response characteristics of urban atmospheric pollutants in the Yangtze River Delta region to the COVID-19 lockdown. The results show that, except O3, the average concentrations of air pollutants during the lockdown (from January 24 to February 10) were lower than that before the lockdown but higher than that after the lockdown, indicating that emission reduction was not the only factor in terms of governing air quality. The ratio of PM2.5/PM10 during the lockdown period was higher than before and after the lockdown, indicating that the secondary generation of aerosols has an important contribution to the fine particle pollution that still occurs during the lockdown period. We observed a significant increase of Ox levels (p < 0.01) during the lockdown, suggesting that atmospheric oxidation capacity may be substantially enhanced in the context of NO2 reduction. Spatially, the O3 typically centered in individual city as hotspots, indicating its nature of local emission and formation. However, other pollutants (including PM2.5, PM10, CO, SO2, and NO2) demonstrated a gradual decrease gradient from north to south, satellite observations pinpointed that North China Plain was the major source of regional transport, which can be further validated by back-trajectory analysis.
