NASA has announced last week that since the COVID-19 pandemic began, space and ground-based observations have shown that Earth's atmosphere has seen significant reductions in some air pollutants.
NASA announced in a press release that through using computer models to generate a COVID-free 2020 for comparison, NASA researchers found that since February, pandemic restrictions have reduced global nitrogen dioxide concentrations by nearly 20%.
NASA presented the results at the 2020 International Conference for High Performance Computing, Networking, Storage, and Analysis.
Nitrogen dioxide is an air pollutant primarily produced by the combustion of fossil fuels used by industry and transportation -- both of which were significantly reduced during the height of the pandemic to prevent the novel coronavirus from spreading, NASA added.
Wuhan, China was the first municipality to report an outbreak of COVID-19. It was also the first to show reduced nitrogen dioxide emissions -- 60% lower than simulated values expected. A 60% decrease in Milan and a 45% decrease in New York followed shortly, as their local restrictions went into effect, the report added.
The drop in pollutant levels before lockdowns was predominately related to the fact that people were probably reducing their transit because the talk of the COVID-19 threat was already happening before government-imposed lockdowns.
Once restrictions were eased, the decreases in nitrogen dioxide lessened, but remained below expected "business as usual" values.