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Cutting-Edge Satellite Instrument Will Track Harmful Pollutants, Improve Air Quality Monitoring and Forecasts

May 20, 2024
A photograph of smog over a city with mountains in the background.

As NOAA busily prepares for the June launch of the last satellite in the GOES-R series, GOES-U, it is already working on the next series of advanced geostationary satellitesthe Geostationary Extended Observations mission, or GeoXO.

When GeoXO launches in the early 2030s, it will include several new state-of-the-art instruments onboard. One of those will be the Atmospheric Composition instrument, or ACX, which will provide critical information about Earth’s atmosphere from geostationary orbit.

The GeoXO ACX, being developed by BAE Systems, will provide hourly observations of air pollutants emitted by transportation, power generation, industry, oil and gas extraction, volcanoes, and wildfires, as well as secondary pollutants generated from these emissions once they are in the atmosphere.

These continuous measurements of our atmosphere’s composition will be a key improvement to air quality monitoring and forecasting, and will help alleviate the health impacts from severe pollution and smoke events across the United States.

“ACX will provide exceptionally detailed information about the connection between weather, climate, and the composition of gases and particles in the atmosphere,” Sherri Hunt said. As the Principal Associate National Program Director of the Environmental Protection Agency’s Air, Climate, and Energy Research Program, Hunt emphasized that these details will enable scientists to ultimately build models that more accurately represent the daily changes in air quality.

Joel Dreessen, the Deputy Program Manager for the Air Monitoring Program at the Maryland Department of the Environment noted that ACX’s more frequent updates and better tracking of emissions will also be vital to understanding the origins–and evolution–of events impacting air quality. 

“Whether it’s international smoke transport or local ozone generated from urban emissions, this knowledge provides the power to make informed decisions,” Dreessen said.

Currently, NOAA’s polar-orbiting satellites take measurements of atmospheric composition, but that information is provided just once daily as the satellites pass over.  Having an atmospheric composition instrument like ACX aboard a geostationary satellite will provide the capability to observe rapidly changing air quality on a much more frequent basis.

“To be able to have that kind of information about ‘invisible’ but unhealthy trace gasses in the atmosphere—such as ozone, nitrogen dioxide, sulfur dioxide and others—could revolutionize the way we communicate air quality impacts with the public,” Dreessen added.

When monitoring threats of air quality, particularly intense wildfire smoke, forecasters stress that timely information is critical for allowing them to assess impacts in real-time and make the proper decisions and communicate the impacts appropriately with the public. 

“This new technology will allow us to see how pollutants evolve during the day and where they are transported,” said Michael Geigert, an air quality meteorologist at the Connecticut Department of Energy and Environmental Protection. “In almost real-time, we will be better able to track aerosol plumes from wildfires and more easily ascertain the source of other pollutants that are hazardous to human health.”

ACX will not only allow for better monitoring of air pollutants, but will provide better data for the forecast models that predict where wildfire smoke and other air quality hazards are moving. “This has the potential to be life changing for groups that are already affected by problems such as heart disease or asthma,” Hunt said.

“We currently rely on smoke models to make our forecasts and for determining how much impact these smoke plumes will have at the ground level,” Geigert noted. “ACX will help us verify the models and make much more frequent adjustments to our forecasts. This would have been extremely useful for our forecasts during the summer of 2023, when some segments of the public were especially vulnerable to the very high levels of smoke particulates that reached the ground level.”

Ultimately, ACXin concert with other NOAA satellite instrumentswill provide scientists with the finer-scale atmospheric data they need for understanding the subtle links between Earth’s atmosphere, weather and climate.

“These types of observations from ACX will help us understand the interplay within the Earth system, like how weather and atmospheric composition interact,”  Dreessen said.