According to a media source, experts say that air quality is improving in countries currently under quarantine due to the coronavirus pandemic. However, they say that it is too early to speak about long-term change.
Photos by the US space agency Nasa are crystal clear , the concentration of nitrogen dioxide (NO2) fell significantly in February in Wuhan, China, the epicenter of the COVID-19 pandemic, changing from a red/orange indicator to a blue one.
NO2 is produced mainly by automobiles, industrial sites, and thermal power plants. However, as China moves past the extremity of its crisis, recent photos from the European Space Agency (ESA) are showing a revival in NO2 emissions.
The ESA in northern Italy, which was locked down to fight a spread of the novel coronavirus, has also observed a striking reduction. A similar move is recorded by the European Environment Agency (EEA) in Barcelona and Madrid where Spanish authorities issued confinement orders in mid-March.
“NO2 is a short-lived pollutant, with a lifetime in the atmosphere of about one day,” said Vincent-Henri Peuch, who belongs to the EU earth surveillance programme Copernicus.
“As a result, this pollutant stays near the emissions sources and can be used as a proxy of the intensity of activity in different sectors,” he told AFP.
Fei Liu, an air quality researcher at Nasa’s Goddard Space Flight Center, noticed the change in China, saying: “This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event.”
During the economic crisis a decade ago, the decrease was noted to be “more continuous in time,” said EEA air quality specialist Albert Gonzalez Ortiz.
In northern Italy, “average NO2 concentration levels have been almost halved on average,” Peuch remarked.
The pollutant can cause the respiratory system to become severely inflamed. As for other countries or regions that have asked people to stay confined at home, including Argentina, Bavaria, Belgium, California, France and Tunisia, specialists are moving the data over to see if the pattern is identical.
Less NO2, however, does not automatically imply purer air.
Nasa’s Earth Observatory confirmed that Beijing encountered episodes of emissions owing to fine particles in February. Due to the presence of small particles and NO2 the air in Paris was also classified as moderately polluted on Friday even though the population had been confined at home for three days already.
Peuch clarified that polluting matter would vary with the environment.
“Some emissions sources, like energy production and residential use of energy are likely not to be decreasing markedly when more people have to stay at home,” he noted.
The concentration of so-called PM2.5 and PM10 particles and carbon monoxide (CO) are “also expected to be reducing over time,” Peuch added.