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Washington (AFP) – A satellite took off early Friday from Florida equipped with a new NASA instrument that will measure air pollution in North America hour by hour, neighborhood by neighborhood. A similar tool fulfills the same mission over Asia from 2020 and another will operate from 2024 in Europe.
This scientific tool, called Tempo, should make it possible to follow the diffusion of pollutants with much more precision than before, from their emitting source and as they are propagated by the wind.
Its applications are multiple: improving alerts to inhabitants in the event of poor air quality, better determining the places where new detectors should be installed in the ground, or even helping research on the impact of air pollutants on health.
But they also measure the pollution caused by fires, which are becoming more frequent due to global warming.
About 40% of Americans (about 137 million people) live in areas with poor air quality, according to the American Lung Association. The poorest areas are disproportionately affected.
Air pollution causes approximately 60,000 premature deaths each year in the United States. It is also harmful to the economy due to its impact on the productivity of workers and even on crops.
The satellites used up to now to carry out this type of evaluation in the United States are at an altitude close to 700 km and go around the Earth fifteen times a day.
“We will be able to have measurements every day over New York, for example at 1:30 p.m.,” Caroline Nowlan, an atmospheric physicist at the Center for Astrophysics, explained at a press conference. But “there’s a lot going on in New York in one day. There are two rush hours that can’t be measured.”
Tempo, which weighs just under 140 kg, will dock with a satellite in geostationary orbit, at an altitude of more than 35,000 km. Therefore, it will revolve around the Earth at the same time that it revolves around itself, which will allow it to always be above North America.
“For the first time, we’ll be able to take hour-by-hour measurements” in this part of the world, Nowlan said.
The geostationary orbit is very common for telecommunication satellites, and it is in one of them that Tempo was inserted: the Intelsat IS-40e satellite.
– Ozone and nitrogen dioxide –
The satellite lifted off on Friday at 0030 local time (0430 GMT) aboard a SpaceX Falcon 9 rocket from the Kennedy Space Center in Florida.
Getting into the correct orbit will take about two weeks, according to Jean-Luc Froeliger, vice president of Intelsat.
From that moment the operations can start.
Tempo will work by analyzing light reflected from cloud surfaces using a spectrometer.
Each gas absorbs light differently, so “you can see what’s in the atmosphere through the colors or wavelengths of the light that’s absorbed,” Nowlan explained.
The first will be that of nitrogen dioxide produced by combustion, in particular of gasoline or diesel cars but also of coal or gas power plants.
Then ozone will be evaluated, which when it is high in the atmosphere protects from the sun’s rays but becomes harmful to health when it is on the ground.
Finally, formaldehyde will be measured, which can be used to infer the presence of volatile organic compounds, that is, those elements “that make certain things smell, like paint, gasoline or markers,” Nowlan said.
Tempo, which will operate for at least two years but probably many more, joins NASA’s fleet of some 25 Earth-observing missions.
A similar tool, called Gems, is already in geostationary orbit to fulfill the same mission over Asia, since its takeoff in 2020. And another, Sentinel-4, should be operational from 2024 to cover Europe.