Coronavirus Outbreak Leads to Huge Drop in China’s Air Pollution

The data, which compares NASA satellite images taken from January 2019 to February 2020, show a massive decline in air pollution and U.S. space agencies believe that this is “partly related” to the economic shutdown as a result of the COVID-19, according to The Guardian.

The maps, which detail the concentration of nitrogen dioxide, a noxious gas emitted by motor vehicles, power plants and industrial facilities, compare values across China from Jan. 1-20, 2020 (before the quarantine was implemented) and Feb. 10-25 (during the quarantine), NASA reported.

The data was collected by the European Space Agency’s Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5 satellite as well as NASA’s Ozone Monitoring Instrument (OMI) onboard the Aura satellite.

Reduction in nitrogen dioxide was first apparent in Wuhan, a city in the Hubei province, China where the virus is believed to have originated. It then eventually spread throughout the country.

“This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event,” Fei Liu, an air quality researcher at NASA’s Goddard Space Flight Center, said.

Every year, China sees a drop in nitrogen dioxide during the Lunar New Year, but it rises again as the festive season ends. Scientists believe that the decrease is more than a typical holiday effect or a weather-related variation as the nitrogen dioxide is observed to be 10%-30% lower than usual this time of year.

“This year, the reduction rate is more significant than in past years and it has lasted longer,” Liu said. “I am not surprised because many cities nationwide have taken measures to minimize the spread of the virus.”

Scientists saw a similar drop during the economic recession in 2008 in several countries, however, the decrease was gradual. They also saw a significant reduction in nitrogen dioxide during the 2008 Beijing Olympics, but it rose again as soon as the event ended.