UI professor’s work now in space, monitoring air quality on Earth

Just after midnight on April 7 along the eastern coast of Florida, Jun Wang saw a blinding light burst across a harbor, followed by a mighty roar.

It was a SpaceX rocket lifting off from the Cape Canaveral Space Force Station and starting its ascent into space. With his wife and two of his kids by his side, Wang watched the rocket climb higher and higher into the inky sky — carrying years of his research with it.

“It was a very crazy and unforgettable moment,” he said.

The rocket carried a NASA instrument nicknamed TEMPO, which stands for Tropospheric Emissions: Monitoring Pollution.

It’s the first-ever space instrument that can monitor air pollutants across North America hour by hour. Dozens of researchers across a breadth of institutions helped create the tool, and many of them watched the rocket disappear into the night sky alongside Wang.

NASA’s TEMPO mission officially began in 2013, when Wang joined the team working on the instrument’s software. The project cost $210 million, with just over $90 million of that total going to instrument development.

Time magazine included TEMPO in its roundup of best inventions from 2023, recognizing its contributions to protecting human health.

Wang is now a professor and chair of chemical and biochemical engineering in the University of Iowa College of Engineering — and Iowa’s lead investigator on the mission.

“It was a team effort I'm lucky to be part of. … These missions cannot be done by just one person,” said Wang. “Many of the problems we have today, like air pollution or climate change, require a team effort.”

How it works

Following the successful rocket launch, a commercial communications satellite now hosts TEMPO about 22,000 miles above the equator. The instrument continuously focuses at North America from space, orbiting at the same speed as Earth’s spin to stay above the continent.

TEMPO has a spectrometer, meaning it measures reflected light to collect data on air pollution. Every hour of daylight, it is programmed to track variations in ozone, nitrogen dioxide and other harmful air pollutants from the Yucatan Peninsula up into Canada. It scans the continent in strips from north to south, gradually moving from the East Coast to the West Coast within 60 minutes before it starts again.

With each hour, it creates high-spec resolution images of North America — down to a 5-by-5-mile square. Previous devices could only achieve about 100 square miles of resolution. Scientists can now zoom in on air pollutants in specific neighborhoods, if they wish.

“Let’s use Cedar Rapids as an example,” Wang said. “We can look at the whole city to see how much pollution there is. But within that city, there are lots of differences among different neighborhoods. If this neighborhood has more traffic and another neighborhood is a little remote, you can see that right away.”

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TEMPO was first powered up on June 8 and performed its first measurements between July 31 and Aug. 2. Full operations began around October.

With its hour-by-hour snapshots, the instrument gives scientists a glimpse of how air pollutants travel over time and weather patterns in several levels of the atmosphere — down to the air we breathe at the ground level.

The system also can respond to on-demand requests for location-specific information during air pollution emergencies, Wang said, like a factory explosion.

“It allows us to know how things are evolving and provides intelligence we need to evacuate neighborhoods or see how (pollutants) get transported downwind,” he said.

South Korea launched a similar instrument in 2020 to collect data over Asia. Another satellite is scheduled to launch next year to hover over Europe and North Africa, comprising a constellation of tools for measuring global air pollutants.

Why it’s important

Compared to other states with more population and industry, Iowa’s air quality is relatively clean, Wang said. But it still suffers from air pollutants — some of which originate in other areas and diffuse elsewhere.

For example, while Canadian wildfires raged earlier this year, the Iowa Department of Natural Resources recorded 162 times that national air quality standards were exceeded as smoke wafted across the U.S. The department also issued about 10 air quality advisories this summer.

Knowing how and where those air pollutants are traveling can better protect communities from the hazards.

“Once (pollutants) are in the air, (they) will spread. And air moves fast,” Wang said. “With this data, we should be able to have timely alerts for the public, better forecasts and better monitoring … to help them avoid exposure to high levels of pollutants.”

TEMPO’s hourly dumps of continental air quality measurements result in mounds of data to verify. Wang, along with other mission members, are helping to sift through the numbers.

The U.S. Environmental Protection Agency will use the measurements to provide public data, pollution forecasts and inventories.

“It's like a snowball growing bigger and bigger because more people are interested in this type of instrument,” Wang said. “This is a really big team effort.”

Brittney J. Miller is the Energy & Environment Reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

Comments: (319) 398-8370; brittney.miller@thegazette.com