Photo/Illutration The average CO2 density growth amount in and around Tokyo between January and April from 2016 to 2019 is shown in the upper side, while the growth level in the same months in 2020 is shown in the lower side. The circle mark in reddish colors signifies higher growth, while those in blueish hues signify lower growth. The data shows that the CO2 density in the air increased at a slower pace during the first four months of this year. (Provided by Japan Aerospace Exploration Agency)

The growth level of carbon dioxide (CO2) density noticeably dropped in and around Tokyo between January and April, as fewer people ventured out due to the new coronavirus pandemic.

The observation was made by the Greenhouse Gases Observing Satellite “Ibuki” operated by the Japan Aerospace Exploration Agency (JAXA).

Sluggish economic activity due to the COVID-19 crisis was believed to be responsible.

The CO2 density in the air currently stands at about 410 ppm (0.041 percent). Seasonal variations are evident every year due to the impact of photosynthesis and breathing.

Over the long-term, the figure has been increasing by 2 ppm annually, a trend attributed to human activity.

CO2 density increases evidently in April. In 2016, the increase registered about 8 ppm in and around Tokyo, according to the Ibuki satellite. But this year, the figure was about 3 ppm, or less than half of the figure.

Even when the average in April between 2016 and 2019 is compared with this past April, a similar trend emerged. When January, February and March are compared, the same pattern continues.

JAXA speculated that the drop in increasing levels of carbon dioxide was due to the slower pace of social and economic activity while people stayed indoors so as not to become infected.

Other big cities, such as Beijing and New York, observed a similar trend.

“I hope that experts in other fields use this information to make valuable contributions in society," said Takeshi Hirabayashi, JAXA's senior chief officer of satellite applications.

For more information on JAXA analytical data on changes in the natural environment and economic activity due to the impact of the new coronavirus, please refer to (