How much did pollution levels drop due to COVID-19 shutdowns?
Today’s Video of the Day from NASA Goddard describes the use of space- and ground-based observations to examine how the COVID-19 pandemic has affected air pollution worldwide.
The scientists found that since February, pandemic restrictions have reduced global nitrogen dioxide concentrations by nearly 20 percent.
Nitrogen dioxide emissions are primarily associated with traffic and industry, which were both greatly reduced during COVID-19 shutdowns.
“We all knew the lockdowns were going to have an impact on air quality,” said study lead author Christoph Keller. “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 research was focused on data from over 5,700 observation sites in 46 countries. Across the metropolitan areas analyzed for the study, 50 of the 61 cities had lower nitrogen dioxide emissions by at least 20 percent and as much as 50 percent.
“In some ways I was surprised by how much it dropped,” said Keller. “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.”
Video Credit: NASA Goddard