As millions of people around the world park their cars and stay home, it’s having a visible effect on the environment, with locales normally known for their smoggy skies seeing a dramatic decrease in air pollution.

Since the UK’s shutdown order went into effect 23 March, air quality there has improved exponentially, with nitrogen dioxide (NO2) levels dropping by 60% in some places over the same period last year, and air pollution in cities like London and Glasgow dropping by half, according to the BBC .

Per the Guardian , tiny particle pollution has seen the largest decreases in London, Birmingham, Bristol and Cardiff, followed by Manchester, York and Belfast; Glasgow and Newcastle have seen less of an impact. Scientists believe those levels are set to drop further as the winds change, as “current easterly winds are bringing additional pollution from continental Europe to Britain."

“The air is definitely much healthier,” York University’s James Lee, who analysed the data, told the Guardian. “[Tiny particles and NO2] are the two air pollutants that have the biggest health impacts on people.”

There’s less pollution in United States as well: Curbed reports that Los Angeles recently had its longest stretch of clean air since 1980, and maps from Descartes Labs indicate that air quality has improved in other US cities as well, Fast Company reports . Residents near northern India’s Himalayas are visible for the first time in 30 years from 200 kilometres away, and in Italy, pollution levels have changed so dramatically that the difference can be seen from space.

According to data gathered from the Copernicus Sentinel-5P satellite, there has been a visible air-pollution decrease over Italy since January, the European Space Agency announced in mid-March, with a notable drop in nitrogen dioxide concentrations in the northern part of the country, where a lockdown had gone into effect just a few days earlier.

“Although there could be slight variations in the data due to cloud cover and changing weather, we are very confident that the reduction in concentrations that we can see, coincides with the lockdown in Italy causing less traffic and industrial activities,”  ESA’s Copernicus Sentinel-5P mission manager Claus Zehner said in a press release.

In  China, pollution also decreased substantially,  due to the coronavirus quarantine, Chinese New Year, and an economic slowdown, NASA Earth tweeted March 4. According to a NASA pollution map, NO2 levels first dropped near Wuhan, a trend that continued as shutdowns were ordered across the country. “This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event,” air quality researcher Fei Liu told NASA Earth Observatory’s Kasha Patel. “This year, the reduction rate is more significant than in past years and it has lasted longer.”

Air pollution is one of the factors thought to increase COVID-19 fatalities, according to recent research. In a study published this week, researchers from Harvard University highlighted the link between breathing in polluted air long-term and contracting the virus. “The results of this paper suggest that long-term exposure to air pollution increases vulnerability to experiencing the most severe COVID-19 outcomes,” the study’s authors wrote.

“There is no silver lining to the Covid-19 situation,” York University’s Lee told the Guardian “But I think it shows we can actually achieve quite a lot without travelling. It shows that if we did work from home more in normal times then we would have an effect on air pollution.”

Some environmental activists are hoping this clear revelation leads to permanent change. "Seeing this drop in air pollution shows that less traffic can quickly lead to cleaner air,” Friends of the Earth clean air campaigner Jenny Bates told the BBC. "Once this dreadful situation is over, we don't want to rush to go back to where we were or worse, and we can't have an accelerated return to business as usual. We can have a better, cleaner future for ourselves and the planet."

This article was originally published on 10 April, 2020 and updated on 14 April, 2020.

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