Analysis of satellite imagery shows reduced NO2 in China, Italy

Screenshot: ESA video

Descartes Labs, a geospatial data analytics company, is using satellite imagery analysis to examine how the coronavirus reduced nitrogen dioxide (NO2) emissions in China.

NO2 is produced by vehicles, power plants and heavy industries such as cement manufacturing, which were shut down during the coronavirus epidemic.

Descartes Labs shared its visualization in a Facebook post. The visualization maps a time series of NO2 levels across Eastern China, Japan and the Korean Peninsula using data from the European Space Agency (ESA)  Sentinel-5P satellite.

Plots of NO2 emissions from 2019 compared to 2020 show declines of nearly 60%. Read more on Descartes Lab’s blog.

Copernicus data shared

In a video provided by ESA, a drop in concentrations in late January is visible in China, coinciding with the nationwide quarantine; from the beginning of March, the nitrogen dioxide levels have begun to increase.

Italy reduction

Copernicus data also reveals the decline of air pollution, specifically nitrogen dioxide emissions, over Italy. This reduction is particularly visible in northern Italy, coinciding with its nationwide lockdown to prevent the spread of the coronavirus.

“Satellites offer a unique vantage point to monitor the health of our planet,” said Josef Aschbacher, ESA’s director of Earth Observation Programmes. “Sentinel-5P is one of seven Copernicus satellites in orbit today. It currently provides the most accurate measurements of nitrogen dioxide and other trace gases from space.

“As nitrogen dioxide is primarily produced by traffic and factories, it is a first-level indicator of industrial activity worldwide,” Aschbacher said. “What is clearly visible is a significant reduction of nitrogen dioxide levels over China, caused by reduced activity due to COVID-19 restrictions, but also the Chinese New Year in January. The Copernicus programme is a perfect example of how space serves all European citizens by combining the political strength of the EU with the technical excellence of ESA.”

“We can certainly attribute a part of the nitrogen dioxide concentration reduction to the impact of the coronavirus,” said Claus Zehner, ESA’s Copernicus Sentinel-5P mission manager. “We currently see around a 40% reduction over Chinese cities, however these are just rough estimates, as weather also has an impact on emissions. We are conducting a detailed scientific analysis which will soon provide more insights and quantified results in the following weeks and months.”

The Copernicus Sentinel-5 Precursor mission, also known as Sentinel-5P, is dedicated to monitoring air pollution by measuring a multitude of trace gases as well as aerosols — all of which affect the air we breathe.