Carnegie Mellon University

Ryan Sullivan

Ryan Sullivan

Professor, Mechanical Engineering

5000 Forbes Avenue
Doherty Hall 2111
Pittsburgh, PA 15213


Dr. Ryan Sullivan is an Associate Professor of Chemistry and Mechanical Engineering at Carnegie Mellon University. He is also a faculty member in the Centre for Atmospheric Particle Studies. Ryan Sullivan has a background in atmospheric and analytical chemistry, single-particle analysis, heterogeneous kinetics, and cloud nucleation research. His research interests include the development of improved aircraft-deployable analytical instrumentation to characterize individual particles in the atmosphere in real-time. These instruments are used to investigate the physicochemical properties of atmospheric particles emitted and produced from a variety of sources, the chemical processes they experience during atmospheric transport, and how these processes modify the ability of particles to nucleate both cloud droplets and ice crystals, thus altering cloud properties and the Earth’s climate. These research endeavors involve equal parts instrument development, laboratory experiments, and field measurements.


  • 2002 Hon. B.Sc., Chemistry, University of Toronto 
  • 2006 M.Sc., Chemistry, University of California, San Diego
  • 2008 Ph.D., Chemistry, University of California, San Diego
  • 2009-2011 Post-Doctoral Fellow and Research Scientist, Colorado State University


Sullivan develops real-time instrumentation to study the chemical evolution of individual particles. These techniques are applied in laboratory and field experiments to determine the environmental impacts of atmospheric particulate matter, such as released from fossil fuel combustion and biomass burning, with a focus on how particles change the properties of clouds and the planet's climate.


Sullivan's current projects investigate physicochemical particle properties using custom single-particle instruments that allow us to rapidly characterize atmospheric aerosols in real-time, one particle after another. He is developing improved analytical methods to measure individual particles using laser ablation mass spectrometry, and laser spectroscopy. These new instruments are utilized in both laboratory studies and field experiments (from ground, ship, and aircraft sampling platforms) to determine the kinetics and products of a variety of atmospheric chemical aging processes (e.g. heterogeneous reaction, aqueous-phase chemistry, gas-to-particle conversion, photochemistry, new particle formation). He is also using small cloud simulation chambers to determine the ability of the chemically processed particles to nucleate both warm cloud droplets, and ice crystals via heterogeneous ice nucleation.


More Publications 

By understanding the properties of individual water particles in the clouds, explains Associate Professor of Mechanical Engineering and Chemistry Ryan Sullivan, we can better predict the onset of severe storms, floods, and droughts—and even human-influenced climate change.