When most people think of ozone, too much hairspray and a hole in the atmosphere over Antarctica might come to mind. But in Utah, it's something we actually interact with on a much more frequent basis.
“There's nothing that's emitting ozone,” said National Center for Atmospheric Research scientist Sam Hall. “It's formed secondarily, and it's bad for human health. It's bad for crops. It makes your car rust faster. It has a lot of side effects because it's so potentially reactive, especially in the presence of sunlight.”
Hall is part of a team studying the formation of ozone in the atmosphere above the state through the end of August.
How they’re doing it is pretty nifty. If you’re in the Salt Lake Valley, you might have seen a plane circling low above the city over the past month. Tucked between multi-million-dollar private jets at the Salt Lake City International Airport is a small, twin-engine prop plane packed with sensitive instruments to measure the makeup of the atmosphere.
Ozone forms when pollution reacts with sunlight. While it does make up an important layer in the upper atmosphere that protects us from much of the sun’s ultraviolet radiation, it can be harmful to people’s health at ground level. In fact, the Utah Department of Environmental Quality tracks ground-level ozone in its air quality dashboard.
“That is really key here because the [Great Salt Lake] has been shrinking for a long time and you're replacing dark water with bright sand, and so there's a lot more light available to break apart molecules, and that can lead to higher ozone production,” Hall said. “So we're here to take a look at that and understand what that means for the larger regional chemistry.”
It’s a joint project between the University of Wyoming, University of Montana, Colorado State University, the Utah Division of Air Quality, NASA and the National Center for Atmospheric Research.
The flights themselves are no small feat. The plane must be constantly hooked up to air conditioning to keep the instruments as cool as possible before takeoff, dropping the onboard temp to near-refrigerator levels. There’s so much packed onto the plane, in fact, that the heat generated by the computers overwhelms the onboard air conditioning. That limits flights to about 90 minutes to two hours at a time.
Lead research pilot Edward Sigel and three others take off from the airport before conducting an intricate set of maneuvers above the Wasatch Front. The plane spirals up and down over parts of the valley and even flies as low as 200 feet above the Great Salt Lake to get accurate data.
“It’s like speed reading for about two hours,” Sigel said. “You are paying attention 100% and working. There is no relaxed time in this airplane.”
The flights are to help fill in an important gap in ozone data
“We have a bunch of ozone ground monitors, and then we have satellites that can measure ozone columns in the atmosphere, but we don't have a lot of information about the in-between of that,” said University of Montana Ph.D. student Amity Deters.
Utah is no stranger to myriad air quality issues. Perennial threats from inversion, toxic Great Salt Lake dust and wildfire smoke are constant reminders of the state’s delicate environment.
The effects of wildfire smoke on ozone are what Colorado State University Ph.D. student Brandon McGuire is focused on. Smoke contains many organic compounds that can react with sunlight and form the gas.
“It's interesting to know kind of how much smoke there is, how much that contributes to the composition of the atmosphere, and how much that could contribute to the ozone formation ultimately,” he said.
Wildfire smoke, like the kind that has clogged Utah’s air this summer, can also be a double-edged sword when it comes to ozone. Because ozone needs sunlight to form, McGuire said heavy smoke layers that partially block out rays could actually decrease the amount of ozone produced.
“I'd like to try and help quantify that and just kind of help maybe understand the reactivity of the smoke in this particular valley.”
With final results of the study expected sometime next year, researchers like Hall hope the data will help inform future air quality decisions.
“By going out and studying and looking at the ozone precursors, you can start to look for mitigation strategies that are going to be most effective,” Hall said. “What do you want to reduce? What's going to have the biggest impact at the lowest economic and political costs?
