HUNTSVILLE, Ala. (Sept. 26, 2017) — Graduate students at The University of Alabama in Huntsville (UAH) are putting finishing touches on hardware they hope will help them better mimic how the atmosphere reacts and interacts with a chemical released by pine trees.
Lee Tiszenkel and Qi Ouyang, both graduate students in UAH’s Atmospheric Science Department, spent seven weeks this summer at the University of Delaware, combining hardware from Dr. Shanhu Lee’s UAH lab with hardware in Dr. Murray Johnson III’s lab at UD. The equipment being installed in UAH’s Cramer Research Hall should help the UAH team come close to having both pieces of that research puzzle all in one place.
“We’re kind of recreating the atmosphere,” Tiszenkel said. “We have attempted to make it as close to nature as possible.”
The chemical in question is alpha pinene (∂-pinene), an organic chemical released into the atmosphere in potentially significant amounts by evergreen trees, but especially by pine trees. In the atmosphere, ∂-pinene reacts with ozone, and the intermediate reaction products react with water, sulfur dioxide, nitrous oxide and ozone.
“It gets oxidized a lot, then it’s more likely to condense on an aerosol particle,” Ouyang said. As those aerosol particles grow, they are more likely to attract other bits until they condense into particles big enough to start forming clouds.
“They can start condensing water to make clouds, but a lot of models don’t understand the aerosol effect on clouds,” Ouyang said. Because ∂-pinene is emitted close to the ground — where trees generally hang out — it might be most likely to contribute to air pollution, smog and other low clouds, although the effects of ∂-pinene carried aloft by convection are not well understood.
The lab in Delaware had a chamber for growing the larger aerosol particles, while Lee’s Aerosol Chemistry Lab had a chamber for “nucleating” the first ∂-pinene reactant particles. Putting them together gave the team an opportunity to see the chemical and physical processes from end to end.
Now Tiszenkel and Ouyang are adding a growth chamber to the UAH setup, “so we can see how the molecules nucleate and grow,” Tiszenkel said.
This research program is supported by the National Science Foundation, including a $450,000 NSF research grant to UAH.
For more information:
Dr. Shanhu Lee, (256) 961-7734
Lee Tiszenkel, firstname.lastname@example.org
Qi Ouyang, email@example.com
Phil Gentry, (256) 961-7618