KEY POINTS

  • NASA satellite data showed a marked drop in air pollutant levels in Northeast US
  • Compared to March 2015-2019 data, nitrogen levels dropped 30% in March 2020
  • Similar air pollutant drops were observed in other parts of the world

Various parts of the world are experiencing declines in air pollution, likely due to the measures being done to combat the coronavirus pandemic. New data from a NASA satellite is now showing a significant drop in air pollution over the Northeast United States, particularly in major metropolitan areas. 

This stark difference in nitrogen dioxide concentrations over Northeast U.S. can be observed by looking at two images showing the measurements by the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite.

March 2015-2019 Pollution Image: Average nitrogen dioxide levels over Northeast U.S. from 2015 to 2019, based on NASA satellite data. Photo: NASA

The first image (above) shows the average nitrogen dioxide concentration over North America from 2015 to 2019, with the areas in dark orange and purple representing higher pollutant concentrations.

North America Air Pollution Image: Markedly lower air pollution over Northeast U.S. on March 2020, based on NASA satellite data. Photo: NASA

The second image represents the data gathered from March 2020, when the nitrogen dioxide concentrations are significantly lower, and the areas affected by high levels of air pollution have also become markedly smaller.

According to NASA, the March 2020 data showed the lowest monthly atmospheric nitrogen dioxide levels of any March in OMI record, which began in 2005 up to the present.

"In fact, the data indicate that the nitrogen dioxide levels in March 2020 are about 30% lower on average across the region of the I-95 corridor from Washington, DC to Boston than when compared to the March mean of 2015-19," NASA said. "Further analysis will be required to rigorously quantify the amount of the change in nitrogen dioxide levels associated with changes in emissions versus natural variations in weather."

Similar patterns have been observed in other parts of the world that are hard hit by the coronavirus pandemic, with some of the first observations of significant air pollutant drop being made in China. By early March, data showed that nitrogen dioxide levels in China had dropped by 10 to 30% compared to the previous years, likely due to the industrial shut down.

Significant declines in air pollutant levels have also been observed in places like Italy and Paris, both of which are places that had to enforce stay-at-home orders in an effort to slow the spread of COVID-19.

"These recent improvements in air quality have come at a high cost, as communities grapple with widespread lockdowns and shelter-in-place orders as a result of the spread of COVID-19," NASA said.