NASA Images Show Nitrogen Dioxide Plummets In China Air Due To Coronavirus (Photo Credit: NASA)
The levels of nitrogen dioxide (NO2) have gone down in China as there is a slowdown in economic activity and curbs on movement due to novel coronavirus outbreak (COVID-19). It is to be noted that the satellite images released by the National Aeronautics and Space Administration (NASA) and the European Space Agency’s (ESA) on Saturday revealed that airborne nitrogen dioxide (NO2) levels have significantly decreased over the country. Importantly, more than 3,000 people have so far died in China from the coronavirus.
NASA released the images and said that there is evidence that the change is at least partly related to the economic slowdown following the outbreak of coronavirus. The maps show concentrations of nitrogen dioxide, a noxious gas emitted by motor vehicles, power plants, and industrial facilities. The maps above show NO2 values across China from January 1-20, 2020 (before the quarantine) and February 10-25 (during the quarantine).
The data were collected by the Tropospheric Monitoring Instrument (TROPOMI) on ESA’s Sentinel-5 satellite. A related sensor, the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite, has been making similar measurements.
At the end of 2019, medical professionals in Wuhan, China, were treating dozens of pneumonia cases that had an unknown source. Days later, researchers confirmed the illnesses were caused by a new coronavirus (COVID-19). By January 23, 2020, Chinese authorities had shut down transportation going into and out of Wuhan, as well as local businesses, in order to reduce the spread of the disease. It was the first of several quarantines set up in the country and around the world.
According to NASA scientists, the reduction in NO2 pollution was first apparent near Wuhan, but eventually spread across the country. Millions of people have been quarantined in one of the largest such actions in human history. As of February 28, 2020, the virus had been detected in at least 56 countries.
“This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event,” said Fei Liu, an air quality researcher at NASA’s Goddard Space Flight Center.
In a statement, NASA said, “The drop in nitrogen dioxide in 2020 also coincided with Lunar New Year celebrations in China and much of Asia. Generally, businesses and factories close from the last week in January into early February to celebrate the festival. Past observations have shown that air pollution usually decreases during this period and then increases once the celebration is over.”
“There is always this general slowdown around this time of the year,” said Barry Lefer, an air quality scientist at NASA. “Our long-term OMI data allows us to see if these amounts are abnormal and why.” Launched in 2004, OMI has been collecting global data on NO2 and various air pollutants for more than 15 years.
Additionally, Liu and colleagues have not seen a rebound in NO2 after the holiday. “This year, the reduction rate is more significant than in past years and it has lasted longer. I am not surprised because many cities nationwide have taken measures to minimize spread of the virus,” she said.
(With Inputs From NASA)