Korean satellite Cheollian starts providing real-time air quality information over Asia

The Korea Times

The Korea Times

National

Forestry

Tue, October 3, 2023 | 07:31

Korean satellite Cheollian starts providing real-time air quality information over Asia

Posted : 2021-03-22 16:04

Updated : 2021-03-22 17:00

Cheollian Satellite 2B / Courtesy of Ministry of Oceans and Fisheries

By Ko Dong-hwan

A Korean climate observation satellite started providing real-time images of air quality over Asia on Monday based on eight different concentration levels of pollution sources and other particulates. Expectations are rising over the climate watchdog role to be played by "Cheollian Satellite 2B" over the region.

Geostationary environment monitoring spectrometer (GEMS) atop Geostationary Korea Multi-Purpose Satellite 2B (GEO-KOMPSAT2B), which is its official name, was launched in February 2020 to monitor movements and concentration levels of nitrogen dioxide, aerosol, ozone, rainfall, three ultraviolet ray-related indices and sulfur dioxide. Images of the satellite's readings are available on the website of the Environmental Satellite Center, an arm of the National Institute of Environmental Research (NIER).

Hovering around 36,000 kilometers above the earth, Cheollian's GEMS scans the region's air quality for 30 minutes every hour starting 8:45 a.m. The satellite scans the region's air quality eight times a day.

Data from Cheollian represents air quality on the surface and throughout the stratosphere up to 50 kilometers above the earth's surface. That's why, according to the Ministry of Environment, the satellite's reading cannot be exactly the same as readings on air pollution sources like PM10 (particulate matters 10 micrometers thick or less) or PM2.5 by on-land scanning devices. Still, the authority said the satellite will hugely contribute to understanding how extensively aerosols and other airborne particulates are spread and concentrated.

The satellite already proved its effectiveness in reading nitrogen dioxide levels through images it took in February. The chemical usually gets in the air from automobile emissions and coal-fired power plants and damages human respiratory organs. Nitrogen dioxide reacts with other chemicals in the air to form ozone.

Images from Cheollian show nitrogen dioxide levels were worse on Feb. 9, left, than on Feb. 13 because of heavier traffic volume. Courtesy of Ministry of Environment

An image from Feb. 9, which was a weekday, showed Seoul and the industrial cities of Ulsan in the southeast and Yeosu in the southwest glowing in red ― the worst grade in the color-scheme for nitrogen dioxide concentration levels. Another image, taken on the weekend four days later, showed the red areas had become visibly smaller in size. The former image showed nitrogen dioxide concentration levels that were 30 percent higher than the latter, which is likely due to heavier traffic volume. Another image taken on Feb 19 at 11 a.m. showed Seoul, Beijing, Tokyo, Hong Kong, Bangkok and Taipei tinged in red.

Cheollian's reading of sulfur dioxide levels is also expected to help monitor the aftereffects of natural disasters across Asia, such as volcanic eruptions and wild fires. At 11 a.m. on March 10, the satellite detected high concentrations of sulfur dioxide after Sakurajima, a Japanese volcano, erupted in Kyushu's Kagoshima Prefecture. An hour later, the satellite detected over China another high-concentration area of the chemical that had drifted eastward from Mount Etna in Italy where a volcano had erupted earlier.

NIER plans to improve Cheollian so it can additionally detect formaldehyde?and glyoxal, or volatile organic compounds that are known pollutants worsening the impact of ozone reduction, photochemical smog and climate change in general.

"GEMS will carry out significant roles in promptly and precisely reading air pollution sources and their movements in order to improve Asia's air quality," NIER president Chang Yoon-seok said.

The Environmental Satellite Center started controlling Cheollian last November after the satellite reached its current position in orbit. The center said Cheollian is the world's first GEMS.

NIER plans to launch a mobile version of the website in June.

aoshima11@koreatimes.co.kr