The color difference is clear: While on a satellite image from February of 2019 is a dark brown stain hanging in the Chinese city of Wuhan, the Region a year later, the sky is blue. Brown means on the scale: extremely high load with nitrogen dioxide (NO2), a pollutant that is poking out from factories, cars and power plants out. Sky blue stands for a low concentration of the gas.

the reason for the suddenly clean air through Wuhan could be, according to the researchers, the outbreak of the Corona Virus. In the Chinese city of millions, the novel Virus, Sars-CoV was discovered-2 in December first. The authorities had set the end of January, the traffic to / from Wuhan, to a large extent and local businesses closed, the spread of the pathogen and to halt the chain of Infection to interrupt.

air quality in Wuhan a year ago and today. Photos: Nasa

"There is evidence to suggest that the Change depends at least in part with the economic slowdown due to the outbreak of the Coronavirus together", say it in a message to Nasa. The US space Agency has released the satellite images, together with the European space Agency Esa. "This is the first Time that I see for a specific event, such a dramatic decline over such a wide area", said the environmental researcher Fei Liu of the Goddard Space Flight Center of Nasa in the message. A decrease in the NO2 concentration have you noticed even during the world economic crisis in 2008, but to a lesser extent, so Liu. The Olympic games in Beijing in 2008, had a short-term impact on air quality.

In January and February will be held in China traditionally, the new year celebrations, in time, factories and businesses have closed. But the Nasa researchers believe that the blatant decline of NO2 in the air is not explained by this. Can these temporary holiday effect to exclude, as compared to the researchers, the data of the years 2005 to 2020, with a clear result: This year, the nitrogen dioxide were values in East and Central China, considerably lower than usually at this time. Even after the new year, the NO2 values started to increase again.

in 2020, the decline is significant and holds much longer. This is no Surprise, says Liu. "Because across the country many cities have taken measures to minimize the spread of the Virus." (jana/cvei)

Created: 02.03.2020, 09:17 PM