The Spring Festival Effect: the change of NO2 column concentration in China caused by the migration of human activities

The Spring Festival is the most important holiday in China, human activity and population mobility may contribute greatly to air quality, especially in the megacities. According to the satellite-based tropospheric nitrogen dioxide (NO2) column and ground-based observational concentration of NO2 in the megacities from 2013 to 2018 around the Spring Festival, we found that NO2 concentration decreases obviously during the Spring Festival and rebounds after the Spring Festival in China, particularly in the megacities. The tropospheric NO2 columns density around Beijing-Tianjin-Hebei region decreases about 40% than the period before the festival, and it in Beijing decreases by 41.6% and rebounds by 22.3%. While under the Coronavirus disease 2019 (COVID-19) pandemic progresses, the tropospheric NO2 columns density in Beijing decreases by 56.2% and rebounds only by 6.8% in 2020.

春节是中国最重要的传统节日，人类活动与人口流动对空气质量影响显著，特大城市地区尤为突出。基于2013至2018年春节前后特大城市的卫星观测对流层二氧化氮（NO2）柱浓度数据与地面NO2观测浓度，我们发现中国境内NO2浓度在春节期间显著下降，节后出现回升，这一现象在特大城市中尤为明显。京津冀地区周边的对流层NO2柱浓度较节前下降约40%，北京市该指标下降41.6%，节后回升22.3%。而在2019冠状病毒病（COVID-19）疫情大流行期间，2020年北京市对流层NO2柱浓度下降幅度达56.2%，节后回升仅为6.8%。