Aerosol Investigations by Thermal Deconvolution and by Quartz Mass Water Uptake

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The application of two new experimental methods (TDEX and QMEX) to answer questions relating to hygroscopicity, composition and the state of mixing for atmospheric aerosols will be investigated. The thermal deconvolution experiment (TDEX) is designed to provide a measure of the two dimensional probability of occurrence surface over the plane having coordinates "aerosol size" and "aerosol volatility." In this way one can gain insight into the molecular composition of aerosol samples broken down by size class; it is also possible with TDEX to derive information on the state of mixing of aerosols and to infer the presence of surfactant films on aerosol cores. The Quartz Mass Water Uptake Experiment (QMEX) yields information on the hygroscopicity of aerosols in different size classifications. Here, aerosols are size-sorted by impaction onto vibrating quartz crystals (Quartz Crystal Microbalance). By determining the alteration in resonant frequency as a function of relative humidity, one can measure Hnels exponential mass increase coefficient. These size-specific hygrograms represent important information on the physical chemistry of the aerosols and have application in cloud physics and atmospheric radiative transfer. The project will attempt to answer questions about the physical chemistry of aerosols in air mass types specifically chosen to provide examples of natural aerosol processes in the free atmosphere. Of particular interest are aerosol debris that has been cycled through nonprecipitating marine clouds, well-aged (e.g. 10-20d) industrial aerosols imported as Arctic haze to Alaska, smoke from wildfires in the Siberian a Canadian taiga, and aerosols in air masses enriched in terpenes.