In Situ Measurements of Hygroscopicity of Aerosol Particles

The hygroscopicity of aerosol particles plays an important role in their evolution in the atmosphere. The Cloud and Aerosol Science Laboratory of the University of Missouri-Rolla, has developed a device to perform airborne and ground based measurements of hygroscopicity. This is accomplished by two Differential Mobility Analyzers (DMA) in series with a saturator between them. The first DMA selects a monodispersely sized dry aerosol sample which is exposed to a known relative humidity in the saturator. The resulting size spectrum, measured by the second DMA, characterizes the hygroscopicity of the sample aerosols. This talk presents a description of the device and the discussion of measurement results