Significant reduction in NO2 concentrations amidst Covid-19: NASA

Researchers at the National Aeronautics and Space Administration (NASA) have investigated the reduction of air pollutants present in the Earth’s atmosphere after the world got riddled with the coronavirus pandemic.

The researchers drew the comparison between pandemic-free 2020 versus coronavirus-induced 2020.

NASA researchers found that since February, pandemic restrictions have reduced global nitrogen dioxide concentrations by nearly 20 per cent. The results were presented at the 2020 International Conference for High-Performance Computing, Networking, Storage, and Analysis.

Nitrogen dioxide is an air pollutant that is primarily produced by the combustion of fossil fuels used by industry and transportation.

Lead author Christoph Keller with the Universities Space Research Association (USRA) at NASA’s Goddard Space Flight Center in Greenbelt, Maryland said in a statement: “We all knew the lockdowns were going to have an impact on air quality...it was also soon clear that it was going to be difficult to quantify how much of that change is related to the lockdown measures, versus general seasonality or variability in pollution.”

The researchers mentioned that no two years are exactly alike. Normal variations in weather and atmospheric circulation change the make-up and chemistry of Earth’s atmosphere.

However, researchers intended to evaluate this year’s reduction as there has been a drastic shift in human behaviour due to the coronavirus.

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20-50% reduction

For the analysis, the researchers received data from 46 countries — a total of 5,756 observation sites on the ground — relaying hourly atmospheric composition measurements in near-real-time.

On a city-level, 50 of the 61 analysed cities show nitrogen dioxide reductions between 20-50 per cent.

“In some ways, I was surprised by how much it dropped. Many countries have already done a very good job in lowering their nitrogen dioxide concentrations over the last decades due to clean air regulations, but what our results clearly show is that there is still a significant human behavior-driven contribution,” Keller added.

Wuhan, China, where the Covid-19 outbreak reportedly began, was also the first to show reduced nitrogen dioxide emissions — 60 per cent lower than simulated values expected. A 60 per cent decrease in Milan and a 45 per cent decrease in New York followed shortly, as their local restrictions went into effect.

The study was published on NASA’s official website.

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