A decline in air pollution coincided with national lockdowns implemented to stop the spread of coronavirus throughout 2020, but now that these measures are being relaxed in some countries, pollution levels return to their previous levels.
Specifically, in China nitrogen dioxide levels returning to pre-COVID-19 levels.
Pollution in China
Data indicates that nitrogen dioxide concentrations in Beijing fell by about 35% between February 2019 and 2020. Similarly, in Chongqing, nitrogen dioxide fell by about a 45% between February 2019 and February 2020.
The average level of air pollutants has recovered and is rising again in China, to pre-COVID-19 levels. The maps show monthly mean concentrations of nitrogen dioxide, derived from data from the Copernicus Sentinel-5P satellite. The map shows the fluctuation of levels between the three periods, with dark red indicating high concentrations of nitrogen dioxide: central and eastern parts of China in February 2019, February 2020, and February 2021.
As explained Claus Zehner, director of ESA's Copernicus Sentinel-5P mission:
We expected air pollution to rebound as lockdowns were lifted around the world. Nitrogen dioxide concentrations in our atmosphere do not depend solely on human activity. Weather conditions such as wind speed and cloud cover also affect those levels, however a large number of these reductions are due to the easing of restrictions. In the coming weeks and months, we expect increases in nitrogen dioxide concentrations also in Europe.
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The news
Nitrogen dioxide levels returning to pre-COVID-19 levels as lockdown eases
was originally published in
Xataka Science
by
Sergio Parra
.