The space agency notes that the significant drop in nitrogen dioxide levels corresponds to the schedule of activity restriction measures taken due to the coronavirus.
“It is the first time that I have seen such a spectacular fall over such a large area, linked to a particular event”, says a NASA researcher. In a press release, Fei Liu, who works in the air quality service at the Goddard Space Flight Center of the American space agency, comments on images showing a very significant reduction in pollution in China, a country hit hardest by the Covid-19 coronavirus.
NASA looked at the levels of nitrogen dioxide, a polluting gas emitted in particular by vehicles and industrial activities, by comparing them over two periods: from January 1 to 10, and from February 10 to 25. It turns out that these rates have dropped considerably, as this map shows, particularly in the regions of Beijing, Hebei, Shanghai, Hong Kong, Chongqing and Chengdu.
The space agency notes that the fall in these nitrogen dioxide levels corresponds to the schedule of restrictive measures taken in transport or in companies, as well as the multiplication of placements in quarantine.
NASA also looked at air quality in the city of Wuhan, the cradle of the epidemic, by comparing it with the same periods last year. From February 10 to 25, 2020, NASA noted values below 125 µmol / m2, when they exceeded 500 µmol / m2 a year ago.
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