Chengming Li1,3, Hui Shang2, Zhihao Cui3, Zhaoxin Dai This email address is being protected from spambots. You need JavaScript enabled to view it.1, Zhaoting Ma1

1 Chinese Academy of Surveying and Mapping, Beijing, China
2 Dongying Natural Resources Bureau, Dongying, Shandong, China
3 Shandong University of Science and Technology, Qingdao, Shandong, China

Received: April 10, 2021
Revised: April 10, 2021
Accepted: May 5, 2021

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

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Cite this article:

Li, C., Shang, H.,Cui, Z., Dai, Z., Ma, Z. (2021). COVID-19 as a Factor Influencing Air Quality? A City Study in China. Aerosol Air Qual. Res.


  • The first time to assess AQI variations in a city dominated by petrochemical industry.
  • The impact of factors on AQI during lockdown period is evaluated quantitatively.
  • During pandemic period, the impacts of exhaust emissions on AQI reduced significantly.
  • It can provide a valuable reference for future research on controlling air pollution.


In late December 2019, coronavirus disease-2019 (COVID-19) emerged. To avert the spread of the pandemic, the Chinese government immediately adopted lockdown measures such as traffic restrictions and factory closure. By analyzing the spatio-temporal distribution of AQI simply in Dongying City, a city dominated by petroleum exploration, this study aims to investigate the impact of short-term lockdown in February 2020 on the air quality. The possible influence of meteorological factors and industry exhaust emissions on the air quality were also considered and assessed. Statistically significant air quality index (AQI) reduced were observed during the short-term lockdown period compared to the same period in 2019: a 24.6% reduction with absolute decrease of 25.4. The difference between the peak and trough value of hourly average AQI during the short-term period was nearly 1/3 that of the value in winter. The COVID-19 pandemic also had slight effects on the spatial characteristics of the AQI. Quantitative analysis demonstrated that the AQI had a strong positive correlation with exhaust emissions with p<0.01, indicating that exhaust emissions contribute to air pollution. During the short-term period, the effect of exhaust emissions on the AQI in Dongying City was significantly reduced, with about 38.3% reduction. This study inferred that the decline in AQI is related to the less movement of traffic and enterprise closure. This research provides a valuable reference for controlling air pollution in Dongying City and other areas with similar conditions.

Keywords: COVID-19 pandemic, Air quality index (AQI), Spatiotemporal characteristics, Industry exhaust emissions, Variations in air quality

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