The first COVID-19 lockdown caused significant changes in urban air pollution levels around the world, but the changes were smaller than expected – a new study suggests.
After developing new improvements to the effect of weather and seasonal trends, such as no.2 Emissions from winter to summer, researchers evaluated changes in ambient no.2, O3 And concentrations resulting from lockdown emission changes in fine particles (PM2.5) 11 Global city: Beijing, Wuhan, Milan, Rome, Madrid, London, Paris, Berlin, New York, Los Angeles and Delhi.
Led by experts from the University of Birmingham, an international team of scientists found beneficial reductions in NO2 After offsetting the impact of the weather, the lockdowns were smaller than expected. In parallel, ozone concentrations increased in cities due to lockdown (improving weather).
No2 Traffic is a major air pollutant from emissions, associated with respiratory problems, while ozone is harmful to health, and damages crops.
Publish their findings today Science advanceThe research team also revealed that concentrations of PM2.5, which can worsen medical conditions such as asthma and heart disease, have decreased in all cities except London and Paris.
Lead-author Zombo Shi, Professor of Atmospheric Biogeochemistry at the University of Birmingham, commented: “Rapid, unprecedented reduction economic activity Provided a unique opportunity to study the effects of the intervention air quality. The emissions changes associated with the initial lockdown restrictions resulted in abrupt changes in air pollutant levels, but their effects on air quality were more complex than we thought, and smaller than we expected.
“Weather changes can mask emissions changes on air quality. Importantly, our study has provided a new framework for assessing air pollution interference by isolating the effects of weather and weather from the effects of emission changes. . “
Roy Harrison, Queen Elizabeth II Birmingham Centenary Professor of Environmental Health, a co-author, commented: “Reduction in NO.2 Will be beneficial for public health – ban on activities, especially traffic, brought immediate decline in NO2 In all cities. If the same level of sanctions remains, the annual average NO2 Most locations of concentrations will comply with WHO air quality guidelines.
William Bloss, Professor of Atmospheric Sciences, who is also a co-author, commented that “we have seen ozone levels rise due to lockdown in all the cities we studied. This is what we expect from the chemistry of air, But it will at least counter. Some health benefits from NO2 Cut. Changes in PM2.5 vary by city Faridabad. Future mitigation measures require a systematic air pollution control approach towards NO.2, O3 And PM 2.5 which is optimized for specific cities, to maximize the overall benefits of air quality changes for human health. “
Scientists in Birmingham used machine learning to capture weather effects and seasonal trends before analyzing data-site-specific hourly concentrations of major pollutants from December 2015 to May 2020.
Air pollution is the greatest environmental risk to human health globally, contributing to 6.7 million deaths each year. The World Bank estimated the cost of air pollution to be $ 3 trillion to the global economy.
Z. Shi el al., “Sudden but smaller than expected changes in surface air quality due to COVID-19 locks.” Science advance (2021). Advances. sciencemag.org/lookup… .1126 / Sciadv.abd6696
University of Birmingham
Quotes: Early COVID-19 lockdown had less impact on urban air quality than earlier beliefs (2021, 13 January), https://naveenbharat.org/news/2021-01-early-covid-lockdowns-impact on 13 January 2021 Retrieved from -urban. .html
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