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Atmospheric Chemistry

Atmospheric aerosols, by backscattering solar radiation, attenuate the full impact of greenhouse gases. However, by absorbing sunlight, they warm the upper troposphere, thereby affecting its thermal stability, melting the mountain glaciers that feed major rivers, and reducing the persistence and reflectance of clouds. Clinical and epidemiological studies reveal that aerosols also induce detrimental health effects. More than half of the mass of tropospheric aerosols consists of complex organic matt
http://pubs.acs.org/doi/full/10.1021/acs.jpca.6b00225
er largely derived from the chemical transformation of (natural and anthropogenic) gas emissions into species that can attach to seed particles. Additionally, organic matter is one of the main contributors to aerosol absorptivity in the near-UV−visible ranges. For the previous reasons, our laboratory studies the missing mechanisms of secondary organic aerosol (SOA) production from heterogeneous oxidations and sunlight photolysis. Our work explores how atmospheric chemical reactions of interest proceed "on surfaces" and "in water" under tropospheric conditions. These studies will contribute to understand the daily cycles of aerosol absorption observed in the field, and that may introduce a key feedback in the earth’s radiative balance.
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References:
Oxidation of Substituted Catechols at the Air-Water Interface: Production of Carboxylic Acids, Quinones, and Polyphenols. E.A. Pillar and M.I. Guzman. Environmental Science and Technology (2017), 51, 4951-4959, DOI: 10.1021/acs.est.7b00232. PDF

Reactivity of Ketyl and Acetyl Radicals from Direct Solar Actinic Photolysis of Aqueous Pyruvic Acid. A.J. Eugene and M.I. Guzman. Journal of Physical Chemistry A (2017),
121, 2924-2935, DOI: 10.1021/acs.jpca.6b11916. PDF

Nitrate Radicals and Biogenic Volatile Organic Compounds:Oxidation, Mechanisms and Organic Aerosol. N.L. Ng, S.S. Brown,
A.T. Archibald, E. Atlas, R.C. Cohen, J.N. Crowley, D.A. Day, N.M. Donahue, J.L. Fry, H. Fuchs, R.J. Griffin, M.I. Guzman, H. Herrmann, A. Hodzic, Y. Iinuma, J.L. Jimenez, A. Kiendler-Scharr, B.H. Lee, D.J. Luecken, J. Mao, R. McLaren, A. Mutzel, H.D. Osthoff, B. Ouyang, B. Picquet-Varrault, U. Platt, H.O.T. Pye, Y. Rudich, R.H. Schwantes, M. Shiraiwa, J. Stutz, J.A. Thornton, A. Tilgner, B.J. Williams, R.A. Zaveri. Atmospheric Chemistry and Physics (2017), 17, 21
03-2162, DOI: 10.5194/acp-17-2103-2017. PDF


Aqueous Photochemistry of Glyoxylic Acid. A.J. Eugene, S.-S. Xia, and M.I. Guzman*. Journal of Physical Chemistry A (2016), 120, 3817-3826, DOI: 10.1021/acs.jpca.6b00225. PDF

Heterogeneous Oxidation of Catechol. E.A. Pillar, R. Zhou, and M.I. Guzman*. Journal of Physical Chemistry A (2015), 119, 10349-10359, DOI: 10.1021/acs.jpca.5b07914. PDF
 
Secondary Organic Aerosol (SOA) Formation from β-pinene + NO3 System: Effects of Humidity and Peroxy Radical Fate. C.M. Boyd, J. Sanchez, L. Xu, A.J. Eugene, T. Nah, W.-Y. Tuet, M.I. Guzman, and N.L. Ng. Atmospheric Chemistry and Physics (2015), 15, 7497–7522. PDF

Catechol oxidation by ozone and hydroxyl radicals at the air-water interface. E.A. Pillar, R.C. Camm, and M.I. Guzman*. Environmental Science & Technology (2014), 48, 14352-14360. PDF

A review of air-ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow. T. Bartels-Rausch, H.-W. Jacobi, T.F. Kahan, J.L. Thomas, E.S. Thomson, J.P.D. Abbatt, M. Ammann, J.R. Blackford, H. Bluhm, C. Boxe, F. Domine, M.M. Frey, I. Gladich, M.I. Guzman, D. Heger, Th. Huthwelker, P. Klan, W.F. Kuhs, M.H. Kuo, S. Maus, S.G. Moussa, V.F. McNeill, J.T. Newberg, J.B.C. Pettersson, M. Roeselova, J.R. Sodeau. Atmospheric Chemistry and Physics (2014), 14, 1587-1633. PDF

Negative production of acetoin in the photochemistry of aqueous pyruvic acid. A.J. Eugene, S. Xia, and M.I. Guzman*. Proceedings of the National Academy of Science of the United States of America (2013), 110, E4274-E4275. PDF

Conversion of iodide to hypoiodous acid and iodine in aqueous microdroplets exposed to ozone. E.A. Pillar, M.I. Guzman*, and J.M. Rodriguez. Environmental Science & Technology (2013), 47, 10971-10979. PDF

Organics in Environmental Ices: Sources, Chemistry, and Impacts. V.F. McNeill, A.M. Grannas, J.P.D. Abbatt, M. Ammann, P. Ariya, T. Bartels-Rausch, F. Domine, D.J. Donaldson, M.I. Guzman, D. Heger, T.F. Kahan, P. Klan, S. Masclin, C. Toubin, D. Voisin. Atmospheric Chemistry and Physics (2012), 12, 9653-9678. PDF 

Concentration Effects and Ion Properties Controlling the Fractionation of Halides during Aerosol Formation. M.I. Guzman*, R.R. Athalye and J.M. Rodriguez. Journal of Physical Chemistry A (2012), 116, 5428-5435. PDF

Second-generation products contribute substantially to the particle-phase organic material produced by β-caryophyllene ozonolysis. Y.J. Li, Q. Chen, M.I. Guzman, C.K. Chan, and S.T. Martin. Atmospheric Chemistry and Physics (2011), 11, 121-132. PDF

Thermochromism of Model Organic Aerosol Matter. A.G. Rincon, M.I. Guzman, M.R. Hoffmann, and A.J. Colussi. Journal of Physical Chemistry Letters (2010), 1, 368-373. PDF

Optical absorptivity versus molecular composition of model organic aerosol matter. A.G. Rincon, M.I. Guzman, M.R. Hoffmann, and A.J. Colussi. Journal of Physical Chemistry A (2009), 113, 10512-10520. PDF

An overview of snow photochemistry: evidence, mechanisms and impacts. A.M. Grannas, A.E. Jones, J. Dibb, M. Ammann, C. Anastasio, H. Beine, M. Bergin, J. Bottenheim, C.S. Boxe, G. Carver, J.H. Crawford, F. Domine, M.M. Frey, M.I. Guzman, D. Heard, D. Helmig, M.R. Hoffmann, R.E. Honrath, L.G. Huey, M. Hutterli, H.W. Jacobi, P. Klan, B. Lefer, J. McConnell, J. Plane, R. Sander, J. Savarino, P.B. Shepson, W.R. Simpson, J. Sodeau, R. von Glasgow, R. Weller, E.W. Wolff, T. Zhu. Atmospheric Chemistry and Physics (2007), 7, 4329-4373. PDF

Photolysis of Pyruvic Acid in Ice: Possible Relevance to CO and CO2 Ice Core Record Anomalies. Guzman M.I., M.R. Hoffmann, and A.J. Colussi. Journal of Geophysical Research (2007), 112, D10123, doi:10.1029/2006JD007886. PDF

Cooperative Hydration of Pyruvic Acid in Ice. M.I. Guzman, L. Hildebrandt, A.J. Colussi, and M.R. Hoffmann. Journal of the American Chemical Society (2006), 128, 10621-10624. PDF

Acidity of Frozen Electrolyte Solutions. C. Robinson, C.S. Boxe, M.I. Guzman, A.J. Colussi, and M.R. Hoffmann. Journal of Physical Chemistry B (2006), 110; 7613-7616. PDF

Photoinduced Oligomerization of Aqueous Pyruvic Acid. M.I. Guzman, A.J. Colussi, and M.R. Hoffmann.
Journal of Physical Chemistry A (2006), 110, 3619-3626. PDF
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Photogeneration of Distant Radical Pairs in Aqueous Pyruvic Acid Glasses. M.I. Guzman, A.J. Colussi, and M.R. Hoffmann. Journal of Physical Chemistry A (2006), 110; 931-935. PDF