Kerri A. Pratt

The Pratt Lab studies the chemical interactions between atmospheric trace gases, particles, clouds, and snow through field-based measurements and sampling in wintertime environments and the Arctic, which is warming faster than anywhere else on Earth. We use a custom-built, field-portable single-particle mass spectrometer to measure the size and chemistry of individual particles in real-time. Trace gas composition is measured using field-portable chemical ionization mass spectrometers. Ambient ion monitor and particle-into-liquid samplers provide online sampling of trace gases and particles for analysis using high sensitivity ion chromatography. Off-line measurements of individual atmospheric particles using electron microscopy provide knowledge of particle morphology and elemental composition. These measurements of trace gases, aerosols, snow, and cloud droplets are coupled with numerical modeling to study chemical mechanisms in the atmosphere and at the air-snow interface. These studies are improving our understanding of the Earth's atmosphere and cryosphere, with implications on climate and air quality.

Representative Publications

Kirpes, R.M., Z. Lei, M. Fraund, M.J. Gunsch, N.W. May, T.E. Barrett, C.E. Moffett, A.J. Schauer, B. Alexander, L.M. Upchurch, S. China, P.K. Quinn, R.C. Moffet, A. Laskin, R.J. Sheesley, K.A. Pratt*, A.P. Ault*. 2022, Solid organic-coated ammonium sulfate particles at high relative humidity in the summertime Arctic atmosphere. Proceedings of the National Academy of Sciences of the United States of America, doi:10.1073/pnas.2104496119.

McNamara, S.M., K.R. Kolesar, S. Wang, R.M. Kirpes, N.W. May, M.J. Gunsch, R.D. Cook, J.D. Fuentes, R.S. Hornbrook, E.C. Apel, S. China, A. Laskin, and K.A. Pratt*. 2020. Observation of road salt aerosol driving inland wintertime atmospheric chlorine chemistry. ACS Central Science, doi:10.1021/acscentsci.9b00994.

Kirpes, R.M., D. Bonanno, N.W. May, M. Fraund, A.J. Barget, R.C. Moffet, A.P. Ault*, and K.A. Pratt*. 2019. Wintertime Arctic sea spray aerosol composition controlled by sea ice lead microbiology. ACS Central Science, doi:10.1021/acscentsci.9b00541.

Wang, S., S.M. McNamara, C.W. Moore, D. Obrist, A. Steffen, P.B. Shepson, R.M. Staebler, A.R.W. Raso, and K.A. Pratt*. 2019. Direct detection of tropospheric atomic bromine leading to mercury and ozone depletion. Proceedings of the National Academy of Sciences of the United States of America, doi:10.1073/pnas.1900613116.

Raso, A.R.W., K.D. Custard, N.W. May, D.J. Tanner, K. Newburn, L. Walker, R. Moore, L.G. Huey, M.L. Alexander, P.B. Shepson, and K.A. Pratt*. 2017. Active molecular iodine photochemistry in the Arctic. Proceedings of the National Academy of Sciences of the United States of America, doi:10.1073/pnas.1702803114.

Pratt, K.A.*, K. D. Custard, P.B. Shepson, T.A. Douglas, D. Pohler, S. General, J. Zielcke, W.R. Simpson, U. Platt, D.J. Tanner, L.G. Huey, M. Carlsen and B.H. Stirm. 2013. Photochemical production of molecular bromine in Arctic surface snowpacks. Nature Geoscience. 6: 351-356.

Pratt, K.A., P.J. DeMott*, J.R. French, Z. Wang, D.L. Westphal, A.J. Heymsfield, C.H. Twohy, A.J. Prenni and K.A. Prather*. 2009. In-situ detection of biological particles in cloud ice crystals. Nature Geoscience. 2: 398-401.

Pratt, K.A., J.E. Mayer, J.C. Holecek, R.C. Moffet, R.O. Sanchez, T. Rebotier, H. Furutani, M. Gonin, K. Fuhrer, Y. Su, S. Guazzotti and K.A. Prather*. 2009. Development and characterization of an aircraft aerosol time-of-flight mass spectrometer. Analytical Chemistry. 81: 1792-1800.

Awards

Research Areas(s)

• Analytical Chemistry
• Environmental Chemistry
• Physical Chemistry

Field(s) of Study

• Mass spectrometry
• Atmospheric trace gases and particles
• Cloud and snow chemistry
• Cryosphere-atmosphere interactions
• Chromatography