NASA has released satellite images that show a dramatic drop in pollution levels in China, which the US space agency says is “partly related” to the coronavirus.
He says there has been a significant decrease in nitrogen dioxide (NO2) – a harmful gas emitted by motor vehicles, power plants and industrial facilities – due to the economic downturn following the release.
COVID-19 started in the Chinese city of Wuhan, which was locked out on January 23, residents were not allowed to leave, and businesses were closed to reduce the spread of the disease.
The reduction in NO2 pollution first appeared near Wuhan, but eventually spread across the country, according to NASA scientists.
Quarantine was the first of several implementations China, then around the world, in what has become one of the greatest actions of its kind in human history.
“This is the first time I have seen such a dramatic drop in such a large area for a specific event,” said Fei Liu, air quality researcher at NASA.
She recalls seeing a drop in NO2 in several countries during the economic recession that started in 2008, but says the decline was gradual.
There was also a reduction around Beijing during the 2008 Olympics, but scientists say this effect was mainly localized around the capital and that pollution levels increased again after the Games ended.
The decrease in NO2 also coincided with celebrations of the Lunar New Year in China and much of Asia.
Typically, businesses and factories close from the last week of January to early February to mark the event.
Previous observations have shown that air pollution generally decreases around this period, but increases after it is over.
But although Lunar New Year may have played a role in the recent decline, researchers believe the decrease is more than a holiday effect or a variation related to weather conditions.
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Ms. Liu did not see a rebound in NO2 after the celebrations.
She said: “This year the reduction rate is greater than in previous years and it has lasted longer.
“I am not surprised because many cities across the country have taken steps to minimize the spread of the virus.”
NASA researchers compared the NO2 values in 2020 with the average quantities detected at this time of year 2005-19.
In 2020, NO2 levels in eastern and central China were significantly lower (10-30% lower) than what is normally observed for this period.
NASA has released satellite images that show a dramatic drop in pollution levels in China, which the US space agency says is “partly related” to the coronavirus.
He says there has been a significant decrease in nitrogen dioxide (NO2) – a harmful gas emitted by motor vehicles, power plants and industrial facilities – due to the economic downturn following the release.
COVID-19 started in the Chinese city of Wuhan, which was locked out on January 23, residents were not allowed to leave, and businesses were closed to reduce the spread of the disease.
The reduction in NO2 pollution first appeared near Wuhan, but eventually spread across the country, according to NASA scientists.
Quarantine was the first of several implementations China, then around the world, in what has become one of the greatest actions of its kind in human history.
“This is the first time I have seen such a dramatic drop in such a large area for a specific event,” said Fei Liu, air quality researcher at NASA.
She recalls seeing a drop in NO2 in several countries during the economic recession that started in 2008, but says the decline was gradual.
There was also a reduction around Beijing during the 2008 Olympics, but scientists say this effect was mainly localized around the capital and that pollution levels increased again after the Games ended.
The decrease in NO2 also coincided with celebrations of the Lunar New Year in China and much of Asia.
Typically, businesses and factories close from the last week of January to early February to mark the event.
Previous observations have shown that air pollution generally decreases around this period, but increases after it is over.
But although Lunar New Year may have played a role in the recent decline, researchers believe the decrease is more than a holiday effect or a variation related to weather conditions.
:: Listen to the Daily podcast on Apple Podcasts, Google Podcasts, Spotify, Spreaker
Ms. Liu did not see a rebound in NO2 after the celebrations.
She said: “This year the reduction rate is greater than in previous years and it has lasted longer.
“I am not surprised because many cities across the country have taken steps to minimize the spread of the virus.”
NASA researchers compared the NO2 values in 2020 with the average quantities detected at this time of year 2005-19.
In 2020, NO2 levels in eastern and central China were significantly lower (10-30% lower) than what is normally observed for this period.