Carnegie Mellon University

Neil Donahue

Neil M. Donahue

Thomas Lord Professor in Chemistry
Professor, Chemical Engineering
Professor, Engineering and Public Policy
Director, Steinbrenner Institute for Environmental Education and Research

Education

Ph.D. Meteorology, MIT, 1991

Research

Atmospheric chemistry, organic aerosol, kinetics, reaction dynamics, radical-molecule reactivity, ozonolysis, mass spectrometry

Projects

Atmospheric Chemistry: Ozonolysis and Organic Aerosols.

His principal interest is in the oxidation chemistry of Earth's atmosphere — specifically the oxidation of organic compounds and the associate radical processes in the atmosphere. Two closely connected areas are ozonolysis chemistry and the chemistry controlling organic-aerosol levels and properties in the atmosphere. Aerosols — fine particulate matter, or PM — are of interest for two major reasons: particles play a central role in climate, and they kill people. The leading uncertainty on the forcing side of climate science is the degree to which cloud properties have changed between 1850 and now due to changes in the number concentrations of fine, water-soluble particles that act as cloud-condensation nuclei (CCN). Also, approximately 50,000 people die prematurely each year in the U.S. alone from inhalation of elevated levels of fine PM. More than half of the fine PM mass is composed of a very complex mixture of highly oxidized organic compounds. They are water soluble and have unknown health effects but appear to correlate positively with observed health endpoints.

Recent research largely directed by Prof. Donahue within the Center for Atmospheric Particle Studies (CAPS) has established that organic aerosol exists in a dynamic balance connecting phase partitioning and oxidation chemistry. Oxidation of large, reduced organics typical of fresh emissions tends to functionalize the carbon backbone, leading to lower vapor pressure products that spend more time in the particulate (condensed) phase, but continued oxidation tends to fragment the carbon backbone as it drives the products towards the oxidative endpoint — CO2. Understanding this multiphase chemistry in the extremely rich and complex mixture that is organic aerosol is a major current research focus.

In parallel, the Donahue group is pursuing the short-lived intermediates involved in gas-phase ozonolysis chemistry, including the carbonyl-oxide (Criegee Intermediate). Reactions in the gas phase show a strong dependence on both pressure and the carbon number because energy transfer from highly-excited reaction products via collisions with the bath gas is inefficient. The group uses both experimental (spectroscopic) and theoretical (quantum chemistry coupled to statistical reaction dynamics) tools to probe the nature and fate of these intermediates.

Publications

Unimolecular Decay of the Dimethyl-Substituted Criegee Intermediate in Alkene Ozonolysis: Decay Time Scales and the Importance of Tunneling
Greg T. Drozd, Theo Kurtén, Neil M. Donahue, and Marsha I. Lester, The Journal of Physical Chemistry A 2017 121 (32), 6036-6045, DOI: 10.1021/acs.jpca.7b05495

Mass accommodation coefficients of fresh and aged biomass-burning emissions
Aditya Sinha, Rawad Saleh, Ellis S. Robinson, Adam T. Ahern, Daniel S. Tkacik, Albert A. Presto, Ryan C. Sullivan, Allen L. Robinson & Neil M. Donahue, Aerosol Science and Technology Vol. 0, Iss. 0, 2018

Reducing secondary organic aerosol formation from gasoline vehicle exhaust
Yunliang Zhao, Rawad Saleh, Georges Saliba, Albert A. Presto, Timothy D. Gordon, Greg T. Drozd, Allen H. Goldstein, Neil M. Donahue and Allen L. Robinson, PNAS 2017 July, 114 (27) 6984-6989. https://doi.org/10.1073/pnas.1620911114

Chapter Five Climate Change and Air Quality in the Developing World Neil M. Donahue
Donahue, Neil M., The Urgency of Climate Change: Pivotal Perspectives (2017), 73.

Wall effects in smog chamber experiments: A model study
Trump, E. R., Epstein, S. A., Riipinen, I., & Donahue, N. M.; Aerosol Science and Technology, 2016, 50(11), 1180-1200.

Probing the evaporation dynamics of mixed SOA/squalane particles using size-resolved composition and single-particle measurements
E. S. Robinson, R. Saleh, and N. M. Donahue, Environmental Science & Technology, 2015, 49, 9724– 9732

Aging of secondary organic aerosol from small aromatic VOCs: changes in chemical composition, mass yield, volatility and hygroscopicity
L. Hildebrandt Ruiz, A. Paciga, K. Cerully, A. Nenes, N. M. Donahue, and S. N. Pandis, Atmospheric Chemistry and Physics, 2015, 15, 8301–8313

Experimental investigation of ion-ion recombination at atmospheric conditions
A. Franchin, S. Ehrhart, J. Leppä, T. Nieminen, S. Gagn ́e, S. Schobesberger, D. Wimmer, J. Duplissy, F. Riccobono, E. M. Dunne, L. Rondo, A. Downard, F. Bianchi, A. Kupc, G. Tsagkogeorgas, K. Lehtipalo, H. E. Manninen, J. Almeida, A. Amorim, P. E. Wagner, A. Hansel, J. Kirkby, A. Kürten, N. M. Donahue, V. Makhmutov, S. Mathot, A. Metzger, T. Petäjä, R. Schnitzhofer, M. Sipilä, Y. Stozhkov, A. Tom ́e, V.-M. Kerminen, K. Carslaw, J. Curtius, U. Baltensperger, and M. Kulmala, Atmospheric Chemistry and Physics, 2015, 15, 7203–7216

Photochemical aging of secondary organic aerosols generated from the photooxidation of polycyclic aromatic hydrocarbons in the gas-phase
M. Riva, E. S. Robinson, E. Perraudin, N. M. Donahue, and E. Villenave, Environmental Science & Technology, 2015, 49, 5407–5416

Saturation vapor pressures and transition enthalpies of low-volatility organic molecules of atmospheric relevance: from dicarboxylic acids to complex mixtures
M. Bilde, K. Barsanti, A. Booth, C. Cappa, N. M. Donahue, G. McFiggans, U. Krieger, C. Marcolli, D. Topping, P. Ziemann, M. Barley, S. Clegg, B. Dennis-Smither, E. Emanuelsson, M. Hallquist, Å . Hallquist, A. Khlystov, M. Kulmala, D. Mogensen, C. Percival, F. Pope, J. Reid, T. Rosenoern, M. Ribeiro da Silva, K. Salo, V. Soonsin, T. Yli-Juuti, N. Prisle, J. Pagels, J. Rarey, A. Zardini, and I. Riipinen, Chemical Reviews 2015 115, 4115–4156

Evaluation of one-dimensional and two-dimensional volatility basis set in simulating the aging of secondary organic aerosols with smog chamber experiments
B. Zhao, S. X. Wang, N. M. Donahue, W. Chuang, L. Hildebrandt, N. L. Ng, and J. M. Hao, Environmental Science & Technology, 2015, 49, 2245–2254

Molecular measurement of neutral clusters during sulfuric acid - dimethylamine new particle formation
A. Kürten, T. Jokinen, M. Simon, M. Sipilä, N. Sarnela, H. Junninen, A. Adamov, J. Almeida, A. Amorim, F. Bianchi, M. Breitenlechner, J. Dommen, N. M. Donahue, J. Duplissy, S. Ehrhart, R. C. Flagan, A. Franchin, J. Hakala, A. Hansel, M. Heinritzi, M. Hutterli, A. Laaksonen, K. Lehtipalo, M. Leiminger, V. Makhmutov, S. Mathot, A. Onnela, T. Petäjä, A. P. Praplan, L. Rondo, S. Schobesberger, J. H. Seinfeld, F. Stratmann, A. Tomé, J. Tröstl, P. E. Wagner, E. Weingartner, C. Williamson, D. Wimmer, P. Ye, U. Baltensperger, K. S. Carslaw, M. Kulmala, D. R. Worsnop, J. Kirkby, and J. Curtius, Proceedings of the National Academy of Sciences, 2014, 111, 15019–15024

Brownness of organics in aerosols from biomass burning linked to their black carbon content
R. Saleh, E. S. Robinson, D. S. Tkacik, A. T. Ahern, S. Liu, A. Aiken, R. C. Sullivan, A. A. Presto, M. K. Dubey, R. J. Yokelson, N. M. Donahue, and A. L. Robinson, Nature Geoscience, 2014 7, 647–650

Appointments

YearsPosition
2015–present Thomas Lord Professor in Chemistry, Professor of Chemical Engineering, and Engineering and Public Policy
2013–present Director, Steinbrenner Institute for Environmental Education and Research
2008–2015 Professor of Chemistry, Chemical Engineering, and Engineering and Public Policy, Carnegie Mellon University
2005–2008 Associate Professor of Chemistry and Chemical Engineering, Carnegie Mellon University
2005–2013 Director, Center for Atmospheric Particle Studies
2000–2005 Assistant Professor of Chemistry and Chemical Engineering, Carnegie Mellon University
1991–2000 Postdoctoral Associate and Research Scientist, Harvard University

Awards and Distinctions

YearsAward
2017 Carnegie Science Award, Environmental Award
2017 2017 Esselen Award, Northeastern Section of the American Chemical Society
2016 ACS Pittsburgh Award
2011 Fellow, American Geophysical Union
2010 Carnegie Institute of Technology Outstanding Research Award
1991–1993 DOE Distinguished Postdoctoral Fellow
1985–1988 NASA Graduate Student Researcher
1985 MIT Jule Charney Award