NASA, South Korea, and the European Space Agency are working together on a “virtual constellation” of space-based instruments to document global air quality in unprecedented detail. For the first time, scientists will be able to track pollution from space on an hourly basis.

The first instrument to launch was South Korea’s Geostationary Environment Monitoring Spectrometer (GEMS) on February 18th, which flew into space mounted on a Korean satellite also tasked with ocean surface monitoring. NASA plans to send a nearly identical instrument to space aboard a commercial communications satellite in 2022, it said in a briefing today. They’ll be followed by the European Space Agency’s two instruments that will join its existing air quality monitoring satellites, with the first taking off in 2023.

Hourly data will better capture pollution that pops up episodically

The data they collect will boost efforts to reign in pollutants including nitrogen dioxide, smog, formaldehyde, and aerosols. Hourly data will better capture pollution that pops up episodically, like rush-hour traffic or a power plant that switches on to meet peak power demands. The satellite-mounted instruments will also be able to see whether pollution within a certain region was generated there or whether it wafted over from another country.

“What’s exciting is getting these pollution sources and pollution transport at different times of the day,” Barry Lefer, a program manager in NASA’s Earth Science Division, said in a press briefing today. “We’ll be able to get more accurate air quality, air pollution forecasts because we’ll know about the sources and how these sources change over time.”

Older space-based instruments have only been able to measure air pollution once a day. They pass over any given point on Earth at the same time each day, as they circle on a Sun-synchronous polar orbit. GEMS became the first air quality sensor to circle the Earth in geostationary orbit, which allows it — and eventually the other instruments in the constellation — to make constant observations of the same area.

GEMS will monitor aerosols and smog over Asia; its data will be available by next year. NASA is interested in following pollution from oil and gas fields, ships and drilling platforms, and rush-hour traffic in North America. The European Space Agency is working to improve the accuracy of its daily air quality forecasts and will home in on Europe and North Africa. Beyond these aims, the data collected can increase our understanding of a wide range of air quality issues that affect human health, scientists collaborating on the project said.

“The recipient of the service and the information about the pollution ranges from the person in the street interested in how the pollution level will be this afternoon to the policymaker who is interested in trends and in the compliance of pollution levels with agreed standards,” said Ben Veihelmann, a principal investigator for ESA in the Netherlands. He pointed out that air pollution in Europe lowers the average life expectancy by two years, according to a recent study.