ESA’s satellite shows air pollution returning to pre-pandemic levels over China

Earth, the only planet on which human beings can live, is in danger of global warming as hazardous air pollutants trigger the environmental crisis. European Space Agency’s (ESA) satellite have revealed air pollution levels before and after quarantine that was implemented due to the coronavirus, or COVID-19 pandemic.

While the countries declared quarantine last year due to the novel coronavirus pandemic that emerged in Wuhan, China, and has spread throughout the world, all gatherings of people have been banned by the governments to prevent the spread of the virus. As a result, the toxic gases coming out of the chimneys of the factories and the traffic density decreased significantly.

Air pollution increased over China

There is, however, an increase in air pollution levels following the easing of restrictions. ESA published a map concerning China prepared from data from the Copernicus Sentinel-5P satellite in February 2019, February 2020 and February 2021.

The map depicts the fluctuation in levels between the three different periods. Dark red indicates high concentrations of nitrogen dioxide. According to the map, nitrogen dioxide concentrations in Beijing dropped by approximately 35% between February 2019 and February 2020. In Chongqing, the level in question dropped by roughly 45% in the same periods. These figures “returned to almost double pre-COVID numbers,” per ESA.

Nitrogen dioxide concentrations over China. Credit: ESA

“We expected air pollution to rebound as lockdowns are lifted across the globe. Nitrogen dioxide concentrations in our atmosphere do not depend on human activity alone. Weather conditions such as wind speed and cloud cover also affect those levels, however a large quantity of these reductions are due to restrictions being eased,” said Claus Zehner, Copernicus Sentinel-5P mission manager.

According to Zehner, Europe will face a similar situation. “In the coming weeks and months, we expect increases of nitrogen dioxide concentrations also over Europe,” he said.

“The special features of the Copernicus Sentinel-5P satellite, with its high spatial resolution and accurate ability to observe trace gases compared to other atmospheric satellite missions, allows us to generate these unique nitrogen dioxide concentration measurement maps from space,” he concluded.