Coronavirus pandemic-induced lockdowns reduced NO2 levels by nearly 20%, says NASA

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For months almost the entire world was observing a lockdown to contain the spread of the deadly novel coronavirus. By April, most countries were under a complete shutdown to stop the contagion and ramp up healthcare facilities to deal with the global health crisis.

A study conducted by the US space agency the National Aeronautics and Space Administration (NASA) has revealed that these measures helped reduce pollution significantly.

NASA researchers have found that nitrogen dioxide, or NO2, (produced by combustion of fossil fuels) levels in the air have gone down by nearly 20 percent since February 2020.

The NASA report was based on data collected from 46 countries. Hourly atmospheric composition measurements from over 5,000 observation sites were studied by NASA experts. They found that 50 of the 61 cities they studied saw 20-50 percent reduction in nitrogen dioxide levels.

“We all knew lockdowns were going to have an impact on air quality…. 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 behaviour-driven contribution,” said Christoph Keller, who is the lead author of the study and is with Universities Space Research Association (USRA) at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

As per NASA findings, China’s Wuhan, which was the epicentre of the coronavirus pandemic outbreak and was the first to impose a lockdown, showed the first reduction in emission level – it was as much as 60 percent lesser than expected. The other region that showed similar reduction in nitrogen dioxide emissions was Milan.

Meanwhile, in New York, which was for long the worst-affected city in the US, pollution levels declined by 45 percent.