COVID-19 as a Factor Influencing Air Quality? A City Study in China

Chengming Li ； Hui Shang ； Zhihao Cui ； Zhaoxin Dai ； Zhaoting Ma

《Aerosol and Air Quality Research》 21卷9期 (2021/09) Pp. 1-13

https://doi.org/10.4209/aaqr.210080

摘要

To prevent the spread of coronavirus disease 2019 (COVID-19), which emerged in late December 2019, the Chinese government immediately adopted lockdown measures, such as restricting traffic and closing factories. By analyzing the spatiotemporal distribution of the air quality index (AQI) values in Dongying, a city dominated by the petrochemical industry (specifically, petroleum exploration), during February 2020, when the strictest measures were in force, this study investigates the effect of short-term lockdowns on air quality. We observed a statistically significant reduction in the monthly average AQI-24.6%, or an absolute decrease of 25.4-compared to February 2019. Additionally, the difference between the maximum and the minimum hourly average AQI dropped to almost one-third of the value that in the normal time during winter. We also assessed the influence of meteorological factors and industrial exhaust emissions. Quantitative analysis revealed a strong positive correlation (p ＜ 0.01) between the AQI and exhaust emissions, confirming the latter's contribution to air pollution. However, this contribution shrunk by approximately 38.3% during February 2020. Our results indicate that the improvement in air quality was related to traffic reduction and enterprise closures during the lockdown, which only marginally affected the spatial distribution of the AQI values. This research serves as a reference for controlling air pollution in Dongying and areas with similar conditions.

關鍵字

COVID-19 pandemic ； Air quality index (AQI) ； Spatiotemporal characteristics ； Industrial exhaust emissions ； Variations in air quality