Special Issue on COVID-19 Aerosol Drivers, Impacts and Mitigation

Ying LThis email address is being protected from spambots. You need JavaScript enabled to view it.1,2 , Haoxiang Xu1 

1 Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
2 Center for Oceanic and Atmospheric Science at susTech (COAST), Southern University of Science and Technology, Shenzhen, China

Received: November 24, 2020
Revised: February 12, 2021
Accepted: May 20, 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.

Download Citation: ||https://doi.org/10.4209/aaqr.200644  

Cite this article:

Li, Y., Xu, H. (2021). Assessment of Reductions in Emission-driven Air Pollution during the Beijing Olympic Games, Shanghai World Expo, Guangzhou Asian Games and Wuhan COVID-19 Lockdown. Aerosol Air Qual. Res. https://doi.org/10.4209/aaqr.200644


  • Emission-driven (ED) factor generally played a much stronger role in all the events.
  • ED effectiveness for air quality improvement of COVID-19 is not as large as expected.
  • Meteorology-driven (MD) effect worsened the air quality during Shanghai Expo event.
  • MD effect improves air quality in Wuhan, Beijing and Guangzhou events.
  • Strategies are less effective for reducing urban NO2 and not work for O3 reduction.


Quantifying and comparing the effectiveness of different emission control strategies can provide insights for policy design and air quality management. In our previous work, we developed a wind-pollution decomposition (WPD) method that provides a robust tool to quantify meteorology-driven and emission-driven impacts on changes in air quality. In this study, we applied this method to quantify emission-driven impacts on the observed air quality changes during the three largest international socioeconomic mega-events in China, namely, Shanghai World Expo in 2010, Beijing Olympic Games in 2008, and Guangzhou Asian Games in 2010. We also applied the method to the air quality variation during the lockdown period in Wuhan due to COVID-19 and compared the emission-driven impacts on air quality among these events. The results quantitatively show that the emission-driven factor generally played a much stronger role (>86%); the meteorology-driven factor promoted pollution mitigation during Wuhan, Beijing and Guangzhou events but worsened the air quality during Shanghai event. The emission-driven pollution reduction was largest in the Wuhan COVID-19 lockdown (64% NO2, 54% PM2.5 reductions), followed by Beijing Olympics (42% PM2.5, 31% NO2 reductions), The Wuhan COVID-19 impact on air quality improvement is not as effective as expected especially for O3, which implies the difficulty of air quality attainment under normal, non-lockdown daysComparison of these events show that shutdown or emission control measures applied to industries and power plants were generally benefit for PM2.5, SO2 and NO2 reduction, while those applied to on-road traffic control are less-effective for reducing NO2 and not works for the mean O3 reduction. The results imply that advanced control measures for vehicle exhaust and control strategies considering the interaction between O3 and NOx/VOC/PM are necessary. In addition, the ongoing supervision of control strategies implementation is one of the key issues for future air quality management in China.

Keywords: Emission controls, Effectiveness, Mega-events, PM10, O3

Share this article with your colleagues 


Subscribe to our Newsletter 

Aerosol and Air Quality Research has published over 2,000 peer-reviewed articles. Enter your email address to receive latest updates and research articles to your inbox every second week.

Aerosol and Air Quality Research (AAQR) is an independently-run non-profit journal, promotes submissions of high-quality research, and strives to be one of the leading aerosol and air quality open-access journals in the world.