NASA study finds that there was nearly 20 percent drop in global nitrogen dioxide levels due to COVID-19 lockdown

As soon as the pandemic hit us and governments across countries had imposed lockdowns, a significant reduction of air pollutants was noticed. Now the National Aeronautics and Space Administration (NASA) has an exact figure of the pollution deviation this year. The data reveals how much pollution would have occurred if we were not facing a pandemic and the percentage drop in nitrogen dioxide emissions in different nations compared to their usual emission percentage. Using computer models, scientists found out that since February this year, the pandemic restrictions have reduced global nitrogen dioxide concentrations by nearly 20 percent. Speaking on the importance of reducing nitrogen dioxide levels in the air, the NASA statement states that air pollutant is “primarily produced by the combustion of fossil fuels used by industry and transportation” and since there was a sudden halt in both at the height of the pandemic, a significant drop in the level was seen. NASA researcher Christoph Keller, who was the project lead, said in a statement that everyone knew “the lockdowns were going to have an impact on air quality” but it was difficult to “quantify how much of that change is related to the lockdown measures, versus general seasonality or variability in pollution”. The problem with coming up with a computer model to study yearly data is that no two years are the same so the model has to factor in the different variables. The researchers collected data from 46 countries and received hourly atmospheric composition measurements in near-real-time. Showing significant changes, 50 of the 61 analysed cities (when computed on a city level) show nitrogen dioxide reductions between 20 to 50 per cent. Keller confessed that he was a bit surprised by the results as he thought the numbers will have a greater bearing on the effort put in to control air pollution in the last decade. But the study clearly showed signs of “a significant human behaviour-driven contribution.”