The COVID-19 pandemic has led to significant changes in human behavior, including the widespread cancellation of significant events, school closures, and teleworking.
Those changes have also led to a dramatic drop in emissions of nitrogen dioxide (NO2) – a pollutant that can cause respiratory problems – over some of the most populated regions of the Northern Hemisphere, according to a new NASA study based on satellite observations.
Air quality has been improving around the world as a result of the COVID-19 pandemic and associated shelter-in-place orders.
A new NASA analysis shows a global decrease of nearly 30% in nitrogen dioxide (NO2) air pollution since stay-at-home orders began, with far more significant reductions observed in heavily populated regions.
NO2 is produced by burning fuel, such as gasoline and diesel, and emissions come primarily from vehicles, power plants, and industrial facilities.
The gas can cause lung damage if breathed in large concentrations over an extended period of time. It also reacts with other chemicals in the atmosphere to form delicate particulate matter (PM2.5), which can be harmful to both human health and the environment.
Between January 1 and April 12, NO2 levels decreased by about 30% in the eastern United States, compared to what they were during the same period from 2005 through 2019.
In Europe, reductions were as high as 60% over Italy and eastern China. Although other pollutants such as carbon dioxide and ozone are also changing due to COVID-19-related behavioral changes, these reductions are primarily related to reduced road traffic, whereas other factors like home energy use and industrial production play a more prominent role in carbon dioxide and ozone.
“We see a clear signature of dramatically reduced NO2 over areas where you would expect it due to changes in emissions caused by the pandemic,” said Helen Worden, lead author of the study published today in the journal Nature Communications. “
Despite efforts to reduce greenhouse gas emissions, researchers say global warming will continue.