What is it about?

China has been actively trying to reduce air pollution but transport, construction, and other industry emissions continue to contribute to reduced air quality. The Covid-19 pandemic and lockdown restrictions slowed down transport and industry activities. This affected not only social and economic conditions, but also environmental conditions. One might wonder: Did the air quality in China change during this period? A 2020 research paper aimed to answer this question. The authors found that levels of the pollutant nitrogen dioxide decreased in over 85% of the cities in mainland China. This drop coincided with a reduction in urban traffic due to the lockdown, and indicate a considerable improvement in air quality. Other pollutants like carbon monoxide, sulfur dioxide, and suspended particulate matter also reduced in over 75% of the cities, but only to a minor extent. In contrast, the ozone levels in most cities increased during the lockdown. Ozone formation is complex, requiring the presence of other air pollutants, and led the authors to question how ozone was being formed. The authors also concluded that vehicular restrictions alone might not significantly improve air quality in China. Ambient air pollutants and other sources of emissions needed to be discovered and targeted.

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Why is it important?

Air pollution causes over 1 million premature deaths every year in China. But we can prevent this. Studying how time and geography changes the concentration of major air pollutants could tell us about the trends and sources of air pollution. Accordingly, governments could then design pollution control strategies. KEY TAKEAWAY: Covid19 restrictions have reduced human commercial activity. This may have resulted in controlling some factors which contribute to air pollution. The current study could be a starting point for future research on air pollutants.

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This page is a summary of: Substantial Changes in Nitrogen Dioxide and Ozone after Excluding Meteorological Impacts during the COVID-19 Outbreak in Mainland China, Environmental Science & Technology Letters, May 2020, American Chemical Society (ACS), DOI: 10.1021/acs.estlett.0c00304.
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