AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Investigation of Hygroscopic Properties of Giant Cloud-Condensation Nuclei with an Aerosol Optical Trap and Humidified Tandem Differential Mobility Analyzer
BENJAMIN E. SWANSON, Rachel Bramblett, Amanda Frossard, University of Georgia
Abstract Number: 846 Working Group: Bioaerosols
Abstract Understanding the links between aerosol particles, clouds, and radiative properties remains a large uncertainty in predicting Earth’s changing energy budget. The ability of a particle to act as a cloud condensation nuclei (CCN) is dependent on both its size and composition. Giant CCN may also have an influence on cloud and precipitation microphysics, and the properties controlling their growth are largely unknown. Natural aerosol particles, such as sea salt and pollen and fungal spore particles have also been observed to behave as giant CCN, in addition to CCN at smaller size ranges. Here, we compare the hygroscopic growth and evaporation of aerosol particles generated from fungal spore and pollen fragments to those generated from seawater and model laboratory aerosol particles. Anemophilous and entomophilous pollen fragments were investigated for chemical and hygroscopic growth differences. We measured the hygroscopic growth of individual, course mode aerosol particles using an aerosol optical trap combined with Raman spectroscopy. We compare those measurements to the growth factors of size-resolved, submicron aerosol particles using the Humidified Tandem Differential Mobility Analyzer (HTDMA). Using the two instruments, we can understand the hygroscopic growth of particles from the submicron CCN range into the coarse mode giant CCN sizes. Fragmented pollen exhibits an increase in hygroscopicity and can act as CCN as a result.