As the world scrambles to mitigate the global novel coronavirus pandemic, there is at least one silver lining among the upheaval: air pollution has dropped.
The Copernicus Atmosphere Monitoring Service (CAMS), an ongoing project led by the European Space Agency, has spotted a dramatic decline of nitrogen dioxide emissions in China. The gas is formed from burning fossil fuels – cars are particularly good at producing it – and it is responsible for the formation of smog and some acid rain.
Satellite images snapped by ESA’s Copernicus Sentinel-5P satellite reveal the level of nitrogen dioxide in the atmosphere has declined somewhere between 20 to 30 per cent in February, compared to previous measurements for the same month in 2017, 2018, and 2019.
As the coronavirus began spreading in Wuhan, the capital of Hubei province, in late December, the Chinese government ordered its citizens to quarantine themselves at home. That meant employees were no longer going to work at power plants or factories. Fewer cars were on the roads, all leading to a drop in nitrogen dioxide emissions.
You can watch the levels dwindle in the video below, showing measurements taken from December 20, 2019 to March 16, 2020.
“We can certainly attribute a part of the nitrogen dioxide emission reduction to the impact of the coronavirus,” said Claus Zehner, ESA’s Copernicus Sentinel-5P mission manager. “We currently see around a 40 per cent reduction over Chinese cities, however these are just rough estimates, as weather also has an impact on emissions.”
Scientists observed similar effects in Italy where Prime Minister Giuseppe Conte has enforced a lockdown of the entire country. The air is clearer particularly in the north, the region inflicted with most COVID-19 cases.
“The decline in nitrogen dioxide emissions over the Po Valley in northern Italy is particularly evident,” Zehner said. “Although there could be slight variations in the data due to cloud cover and changing weather, we are very confident that the reduction in emissions that we can see, coincides with the lockdown in Italy causing less traffic and industrial activities.”
As people in other countries, such as the US and UK, prepare to hunker down at home, ESA’s Copernicus Sentinel-5P Satellite should spot similar declines in nitrogen dioxide across different parts of the world. The coronavirus has infected 244,725 people across 178 countries so far, killing more than 10,000, according to some stats. ®