Chemical Engineering Colloquia Seminar: Neil Donahue, Carnegie Mellon | |||
| Date: | October 13, 2009 from 4:00 pm to 5:00 pm EDT | ||
| Location: | Columbia University Morningside Campus 825 Mudd |
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| Contact: | For further information regarding this event, please contact Mary Ko by sending email to mk2678@columbia.edu or by calling 212-854-4453. | ||
Aging Gracefully: Organic Particulate Matter as an Intermediate State Driven by Phase Partitioning and Oxidation Chemistry Unlike many compounds found in atmospheric particulate matter, most organics are intermediates between chemically reduced emissions and fully oxidized carbon dioxide. Consequently, particulate phase organic carbon is part of an extremely dynamic system driven principally by gas-phase organic oxidation chemistry and controlled by phase partitioning of complex mixtures. In the week or so that most carbon associated with organic aerosol remains in the atmosphere after emission, the material will undergo many generations of oxidation chemistry. In some cases this oxidation adds functional groups to the carbon backbone (we call this the functionalization branch), but in some cases the carbon backbone is cleaved (we call this the fragmentation branch). Ultimately fragmentation wins out, but early on functionalization can drive vapor pressures down by many orders of magnitude. This simple framework defines organic aerosol behavior. We shall discuss several examples, applying the framework to evaporated primary emissions (ie, motor oil) and the aging of biogenic secondary organic aerosol. Columbia University |
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