Faculty News Breath of Fresh Air


Ryan Sullivan Brings Nanoscale Perspective on Air Quality Ryan Sullivan


Assistant Professor Ryan Sullivan is the most recent addition to the MechE faculty—and he brings a unique research perspective to the Department. With a specialization in atmospheric chemistry, Sullivan studies the complex relationships among air pollution, particulate matter, cloud formation, and climate change. He achieves this by analyzing individual


nanometer-sized particles with specialized instrumentation. Growing up in his native Toronto, Sullivan was interested


in environmental chemistry from an early age. He earned a B.S. in Chemistry, with a specialization in environmental chemistry, from the University of Toronto in 2002. Sullivan then earned both an M.S. (2006) and a Ph.D. (2008) in Chemistry from the Univer- sity of California, San Diego (UCSD). Before joining MechE in January, Sullivan served as a Post-Doctoral Fellow and Research Scientist at Colorado State University.


While at UCSD, Sullivan was part of a team that co- authored a paper published in Proceedings of the National Academy of Sciences called “Detection of Oxygen Isotopic Anomaly in Terrestrial Atmospheric Carbonates and Its Impli- cations to Mars.” The paper won the 2011 Cozzarelli Prize, which recognizes outstanding contributions to the disci- plines represented by the National Academy of Sciences.


INNOVATION TAKES OFF Sullivan’s research endeavors focus on the development of improved analytical instrumentation to characterize individ- ual atmospheric particles and their interactions with clouds. These instruments can be deployed at remote sampling sites during intensive atmospheric chemistry field campaigns. Their installation in scientific aircraft, such as the Department of Energy’s G-1 aircraft, enables researchers to measure in situ the composition of individual particles both in clear air and within clouds.


Sullivan has used this unique instrumentation to investigate the physicochemical properties of atmospheric


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particles emitted and produced from a variety of sources, the chemical processes they experience during atmospheric transport, and how these processes affect their ability to nucleate both warm cloud droplets and ice crystals. Sullivan’s research involves equal parts instrument development, labora- tory experiments, and field measurements. At MechE, Sullivan will continue his efforts to investigate physicochemical particle properties using custom instruments that allow him to rapidly characterize atmospheric aerosols in real time, one particle after another. This research includes developing improved analytical methods that rely on both laser ablation mass spectrometry and Raman spectroscopy. Sullivan’s new instruments will be utilized in both laboratory studies and field experiments that rely on ground-based, ship- mounted, and aircraft-mounted sampling platforms. Small cloud simulation chambers will also be used to determine the ability of chemically processed particles to nucleate warm cloud droplets and ice crystals via heteroge- neous ice nucleation.


MECHE: A NATURAL FIT Sullivan was drawn to Carnegie


Mellon because of its world-renowned Center for Atmospheric Particle Studies (CAPS). This Center consists of five interwo- ven research groups directed by faculty members associated with five academic departments at the University, including MechE.


“Atmospheric chemistry is a very specialized area, with only about 100 faculty in this field in the U.S.,” says Sullivan. “Carnegie Mellon is known as a center of transformative research in this area, with a lot of expertise and equipment already in place to support my research.”


While Mechanical Engineering might seem an odd fit for an atmospheric chemist, Sullivan feels right at home in the Department. “The field of mechanical engineering was originally tied to air-quality issues because of the pollution caused by combustion processes,” notes Sullivan. “But today the collaborative, interdisciplinary nature of MechE allows me to expand the focus to encompass the mechanics and chemistry of air quality and cloud nucleation at the individual particle level.”•


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