Chemical Oxidation Reactions and Hydrophobic-to-Hydrophilic Aging of Atmospheric Organic Aerosol Particles

We are investigating the reactivity of organic aerosol particles, particularly their conversion from hydrophobic to hydrophilic characteristics during processing by atmospheric oxidants such as ozone. Once hygroscopic, organic particles alter cloud properties (e.g., duration and brightness) by serving as the nuclei for water condensation. Quantification of these effects is limited, however, because the compositions, morphologies, and reactivities of organic particles are poorly understood. Laboratory studies are essential for understanding and quantifying complex particles and their chemical and physical processes. A key need is an elucidation of the chemical reactions between the organic particulate matter and gas-phase oxidants such as ozone. Our work is focused on ozone heterogeneous chemistry as a proxy for understanding the role of layer thickness in the chemical transformations of surface and interior layers of complex, multicomponent particles.

We are grateful for NSF (ATM 0215357; ATM0513463) and Camille and Henry Dreyfus Foundation (EP-00-003) support.

Publications

1. J.S. Shilling, S.M. King, M. Mochida, D. Worsnop, and S.T. Martin, "Mass Spectral Evidence that Small Changes in Composition Caused by Oxidative Aging Processes Alter Aerosol CCN Properties," Journal of Physical Chemistry A, 2007, 111, 3358-3368. PDF File. Supporting Information.

2. Mochida, M, Y. Katrib, J.T. Jayne, D.R. Worsnop, and S.T. Martin, "The Relative Importance of Competing Pathways for the Formation of High-Molecular-Weight Peroxides in the Ozonolysis of Organic Aerosol Particles," Atmospheric Chemistry and Physics, 2006, 6, 4851. PDF File. Correction.

3. Katrib, Y., Biskos, G., Buseck, P.R., Davidovits, P., Jayne, J.T., Mochida, M., Wise, M.E., Worsnop, D.R., and Martin, S.T., "Ozonolysis of Mixed Oleic-Acid/Stearic-Acid Particles: Reaction Kinetics and Chemical Morphology," The Journal of Physical Chemistry A, 2005, 109, 10910-10919. PDF File.

4. Hung, H.M., Katrib, Y., and Martin, S.T., "Products and Mechanisms of the Reaction of Oleic Acid with Ozone and Nitrate Radical," The Journal of Physical Chemistry A, 2005, 109, 4517-4530. PDF File.

5. Katrib, Y., Martin, S.T., Rudich, Y., Davidovits, P., Jayne, J.T., Worsnop, D.R., "Density Changes of Aerosol Particles as a Result of Chemical Reaction," Atmospheric Chemistry and Physics, 2005, 5, 275-291. PDF File.

6. Katrib, Y., Martin, S.T., Hung, H.M., Rudich, Y., Zhang, H., Slowik, J., Davidovits, P., Jayne, J.T., Worsnop, D.R., "Products and Mechanisms of Ozone Reactions with Oleic Acid for Aerosol Particles Having Core-Shell Morphologies," Journal of Physical Chemistry A, 2004, 108, 6686-6695. PDF File.