PM2.5 and Ozone only slightly reduced during the COVID lockdown in China

A typical, polluted day in Zhengzhou, China

A recent study by the University of Leeds and the Southern University of Science and Technology in Shenzhen divulged PM2.5 had only a small reduction across China and it was not lowered at all in Northeast China. The PM2.5 reduction of 11% across China was disappointing in comparison to the reduction 27% of NO2 across China.  

Lead author Ben Silver, from the University of Leeds, said: “PM2.5 particles had only a modest reduction and are the most harmful constituent of air pollution, as they travel deep into the lungs and bloodstream and damage the lungs and heart.

Furthermore, the research group found nearly no change in ozone concentrations from the COVID-19 pandemic control measures put in place. 

Professor Dominick Spracklen, senior author from the University of Leeds, said: “Although China’s air quality has improved in recent years, indoor and outdoor air pollution still has serious health impacts, with 12% of deaths in China in 2017 attributable to it. Understanding trends in air quality is therefore essential to assess the effectiveness of recent air quality measures and help inform future air pollution mitigation. The application of control measures during the COVID-19 outbreak enabled us to analyse the potential air quality improvements resulting from a reduction in emissions.”

Concentrations of PM2.5 within China are shaped by emissions from residents. With lockdowns in place keeping people at home more, the pandemic control measures did not aid in reductions of PM2.5 or ozone conentrations.

Professor Spracklen added: “The modest improvement in air quality during the lockdown, despite very large reductions in emissions from some sources such as traffic, highlights the challenge facing China as it tries to further improve air quality."

Further Information: 

The original article Lockdown in China saw only a modest drop air pollution is published the Leeds Global News on July 28, 2020

The paper The impact of COVID-19 control measures on air quality in China is published in Environmental Research Letters on July 28, 2020.

For additional information contact the University of Leeds press office at pressoffice@leeds.ac.uk

Image: Zhengzhou, China. Credit: V.T. Polywoda

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