MISSOULA – University of Montana researcher Lu Hu contends our understanding of wildfire smoke is a bit hazy. But the atmospheric chemist recently earned a prestigious federal award to take a deep dive into the true nature of the smoke that clouds our Western skies.

Dr. Hu’s award is from the Faculty Early Career Development Program. CAREER awards are among the most respected National Science Foundation awards, given to promising early career faculty members to provide a foundation for a lifetime of leadership integrating education with research.

Hu will use the five-year, $800,000 grant to improve the ability of researchers to analyze the true chemical composition of wildfire smoke, as well as improve air-quality models.

“I feel pretty good about earning this award,” he said. “It’s nice to be recognized by my colleagues in the field, and it means what we do is really important. We need to study in smoke what we cannot see with our human eyes – especially when it causes respiratory and other diseases.”

A native of China, Hu earned his Ph.D. from the University of Minnesota before becoming a postdoc at Harvard for several years. He joined UM in 2017, where he and his collaborators immediately embarked on a research project that involved flying a plane through smoke billowing off active wildfires. The plane carried a mass spectrometer instrument to minutely analyze what was in the smoke.

Hu is most interested in volatile organic compounds. VOCs in their gas phase can diffuse, transform and travel. Many can have direct negative impacts on human health. Science has the ability to measure about 150 VOCs in the atmosphere, but there are many more to discover. Hu said mass spectrometry is used to identify and quantify VOCs.

“When we look at smoke, we see the particulate matter,” he said. “The actual chemical composition is much more complex. So we can examine VOCs and rank them in terms of what are the most important for human health impacts. We also rank them in terms of how reactive they are and their ability to generate secondary pollutants.”

He said many VOCs are hazardous and regulated by the Environmental Protection Agency. Wildfires are the second leading producer of VOCs. Trees – oddly enough – are the No. 1 producer globally.

“VOCs can be produced by plants for many reasons – as byproducts of photosynthesis, plant growth, defense, induced by various stresses or even for communication,” Hu said. “What you smell when walking in a ponderosa pine forest or cutting a Christmas tree is VOC. You are fine around that in remote areas. But VOCs are volatile and can mix with human-caused pollutants like NOx [nitrogen oxides]. So if you have VOCs from trees or wildfire smoke next to heavy traffic from cars, it becomes this perfect atmospheric cocktail where all these ingredients come together in sunlight, and that can be bad.”

Bad means formation of substances like ozone. High in the atmosphere, ozone is good because it protects us from harmful ultraviolet radiation. But ground-level ozone is regulated by the EPA and can aggravate lung problems such as asthma, emphysema and bronchitis. VOCs also may produce other harmful chemicals, like formaldehyde.

“We cannot measure VOCs well,” Hu said. “This project will work to improve our analytical skills – to improve our use of mass spectrometry – to better quantify them. With all our current models, we still cannot predict the formation of ozone when we have wildfire smoke.”

Some VOCs in wildfire smoke are classified as a group of substances called furans, which possibly can be carcinogenic. Furans are produced during combustion processes like power generation and burning fossil fuels. Hu said the lifetime for most furans is about an hour, after which they “react out” and transform into other things that also are potentially harmful.

When the analytics improve, Hu then hopes to update and improve air quality models.

“With big cities like Salt Lake City or Denver, wildfires bring in additional pollutants – additional VOCs – and can mix with local pollutants to generate ozone particulate matter,” he said. “All the current air quality models don’t simulate these very reactive furans. Lacking those in the models are part of the reason we cannot predict ozone correctly. So that’s the direction we are heading to.”

As part of his research project, Hu will fund the continuation of a long-term, air-monitoring site based on the fourth floor of UM’s Clapp Building. He said Missoula is an ideal location for the site because the area acts as a natural receptor for smoke traveling from the West Coast and British Columbia. The site was launched by his UM colleague and researcher Dr. Bob Yokelson, with Hu adding in VOC measurements.

The CAREER award also will fund a wildfire smoke exhibit and curriculum with UM’s spectrUM Discovery Area, a hands-on science center that inspires a culture of learning and science for children and others. (On the day of this interview, Hu was excitedly ordering low-cost carbon dioxide sensors for the exhibit.)

While working the lab, Hu is assisted by three graduate students. He also has two postdocs on his team, and he said the CAREER award will support one additional graduate and another postdoc for two years. He also recruits a UM undergraduate lab worker from his chemistry classes.

And when he isn’t studying wildfire smoke and teaching, he also co-directs the statewide Montana Science Fair for middle and high school students, which has been held at UM since 1955.

Hu earned the CAREER award in his last year of eligibility, so he feels fortunate. “Getting an award like this is good,” he said. “It’s a rewarding moment for a faculty member, like seeing your students grow.”

- by Cary Shimek, UM News Service -

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