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My interests are in the area of heterogeneous atmospheric chemistry, focusing on the chemical, physical and optical properties of atmospheric particulate.  In addition to fundamental studies of particles, we are also exploring how atmospheric particulate impacts current problems such as stratospheric ozone depletion, global climate change, urban smog and visibility degradation.

In addition to studies of atmospheric aerosols on current-day Earth, we are also probing the particles that might have been present at the earliest times in Earth’s history.  We are interested in how those particles might have impacted the climate of early Earth and the development of life on Earth.  As a parallel to early Earth, we are also studying aerosols and clouds on other planetary bodies such as Mars, Venus and Titan.

Our work is primarily laboratory based, but involves collaborations with theory teams and those involved in observations and fieldwork.  Primary support for our work comes from the National Science Foundation and NASA.

Hawkins, L.N., M.J. Baril, N. Sedhi, M.G. Galloway, D.O. De Haan, G.P. Schill, and M.A. Tolbert (2014), Formation of semisolid, oligomerized aqueous SOA: Lab simulations of cloud processing, Environmental Science and Technology, in press, doi:10.1021/es4049626.  

Schill, G.P., D.O. De Haan, and M.A. Tolbert (2014), Heterogeneous ice nucleation on simulated secondary organic aerosol, Environmental Science and Technology, in press, doi:10.1021/es4046428. 

Robinson, C.B., G.P. Schill, K.J. Zarzana, and M.A. Tolbert (2014), Impact of organic coatings on optical growth of ammonium sulfate particles, Environmental Science and Technology, 47, 13339-13346, doi:10.1021/es4023128. 

Hörst, S.M. and M.A. Tolbert (2013), In situ measurements of the size and density of Titan aerosol analogues, Astrophysical Journal Letters, 770, L10, doi:10.1088/2041-8205/770/1/L10. 

Trainer, M.G., J.A. Sebree, Y.H. Yoon, and M.A. Tolbert (2013), The influence of benzene as a trace reactant in Titan aerosol analogs, Astrophysical Journal Letters, 766, L4, doi:10.1088/2041-8205/766/1/L4. 

Baustian, K.J., M.E. Wise, E.J. Jensen, G.P. Schill, M.A. Freedman, M.A. Tolbert (2013), State transformations and ice nucleation in amorphous (semi-)solid organic aerosol, Atmospheric Chemistry and Physics, 13, 5615-5628, doi:10.5194/acp-13-5615-2013. 

Schill, G.P., and M.A. Tolbert (2013), Heterogeneous ice nucleation on phase-separated organic-sulfate particles: effect of liquid vs. glassy coatings, Atmospheric Chemistry and Physics, 13, 4681-4695, doi:10.5194/acp-13-4681-2013. 

Schill, G.P., and M.A. Tolbert (2012), Depositional ice nucleation on monocarboxylic acids: Effect of the O:C ratio, Journal of Physical Chemistry A, 116, 6817-6822, doi:10.1021/jp301772q. 

Connelly, B.M., D.O. De Haan, and M.A. Tolbert (2012), Heterogeneous glyoxal oxidation: A potential source of secondary organic aerosol, Journal of Physical Chemistry A, 116, 6180-6187, doi:10.1021/jp211502e. 

Zarzana, K.J., D.O. De Haan, M.A. Freedman, C.A. Hasenkopf, M.A. Tolbert (2012), Optical properties of the products of alpha-dicarbonyl and amine reactions in simulated cloud droplets, Environmental Science and Technology, 46, 4845-4851, doi:10.1021/es2040152. 

Trainer, M.G., J.L. Jimenez, Y.L. Yung, O.B. Toon, and M.A. Tolbert (2012), Nitrogen incorporation in CH4-N2photochemical aerosol produced by far ultraviolet irradiation, Astrobiology, 12, 315-326, doi:10.1089/ast.2011.0754. 

Baustian, K.J., D.J. Cziczo, M.E. Wise, K.A. Pratt, G. Kulkarni, A.G. Hallar, and M.A. Tolbert (2012), Importance of aerosol composition, mixing state, and morphology for heterogeneous ice nucleation: A combined field and laboratory approach, Journal of Geophysical Research- Atmospheres, 117, D06217, doi:0.1029/2011JD016784. 

Wise, M.E., K.J. Baustian, T. Koop, M.A. Freedman, E.J. Jensen, and M.A. Tolbert (2012), Depositional ice nucleation onto crystalline hydrated NaCl particles: A new mechanism for ice formation in the troposphere, Atmospheric Chemistry and Physics, 12, 1121-1134, doi:10.5194/acp-12-1121-2012. 

Gough, R.V., V.F. Chevrier, K.J. Baustian, M.E. Wise, and M.A. Tolbert (2011), Laboratory studies of perchlorate phase transitions: Support for metastable aqueous perchlorate solutions on Mars, Earth and Planetary Science Letters, 312,371-377, doi:10.1016/j.epsl.2011.10.026.