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dc.contributor.authorGreenwald, Robyen_US
dc.date.accessioned2005-09-16T15:19:01Z
dc.date.available2005-09-16T15:19:01Z
dc.date.issued2005-08-02en_US
dc.identifier.urihttp://hdl.handle.net/1853/7253
dc.description.abstractThis thesis concerns various aspects of the influence of atmospheric particulate matter on the terrestrial system. In Part I, the radiative influence of particulate matter on the production of crops is explored using the CERES crop model. It is known that the presence of aerosols in the atmosphere simultaneously reduces the amount of sunlight reaching the surface and increases the fraction of that light which is diffuse. Reduction of the total amount of sunlight tends to slow the rate of photosynthesis occurring in plants while increasing the fraction which is diffuse tends to increase the net rate of photosynthesis by more evenly distributing sunlight throughout all layers of a plant canopy. The CERES crop model was modified to estimate the influence of both a reduction in total sunlight and an increase in the diffuse fraction. Model simulations were performed for rice, maize and wheat at a variety of locations and found the likely influence of aerosols on crop production to be a 0-10% reduction in yield compared to the base case. In Part II, the concentration and size distribution of water-insoluble aerosols (WIA) is explored. It has been well-established that atmospheric particulate matter influences the planetary radiation budget both directly and indirectly. The magnitude of these influences is related to particle solubility. A new technique was developed to provide these measurements in real-time. This instrumentation was evaluated in a laboratory setting and implemented into several field studies. Results from these sampling campaigns indicate that in areas heavily influenced by motor vehicle traffic, the WIA concentration is dominated by particulate soot. Many episodes of high levels of crustal dust were also observed. At these times, the WIA size distribution shifted toward larger sizes in a characteristic manner. This suggests that this method is useful for detecting insoluble mineral aerosols as well as particulate soot and that examination of the WIA size-distribution may provide a basis to distinguish between the two.en_US
dc.format.extent6848367 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectElemental carbonen_US
dc.subjectAerosols
dc.subjectSoot
dc.subjectParticulate matter
dc.subjectMineral aerosols
dc.titleReal-time measurement of the water-insoluble aerosol size distribution: instrument development and implementationen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentCivil and Environmental Engineeringen_US
dc.description.advisorCommittee Chair: Michael H. Bergin; Committee Member: Armistead Russell; Committee Member: James Mulholland; Committee Member: Jean-Luc Jaffrezo; Committee Member: Rodney Weberen_US


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