Abstract View
Influence of Various Surfactants of Hygroscopic Growth of Course Mode Aqueous Aerosol Particles
BENJAMIN SWANSON, Amanda Frossard, Rachel Bramblett, University of Georgia
Abstract Number: 473
Working Group: Aerosols, Clouds and Climate
Abstract
Aerosol particles have a myriad of influences on the global climate budget, but significant uncertainties in their effects remain. The constituents of sea spray aerosols from open-ocean sources may be influenced by organic and surfactant materials on the ocean surface. Surfactants present in aerosol particles, whether natural or anthropogenic, have largely been ignored within large-scale climate modeling. Examinations of the effects of surfactants present in droplets have shown that both the surface tension and hygroscopic growth of droplets can be drastically affected. Here, we compare the effect of different surfactants, including various surfactant ionic classes, structures, and sizes, on the hygroscopic growth and surface tension of aqueous course mode particles. We also examine the effect of these surfactant classes as a function of particle size for these individual aqueous particles. These growth parameters were measured using an Aerosol Optical Trap (AOT) combined with Raman spectroscopy, which traps and sizes individual aqueous aerosol particles. For a relative humidity (RH) shift from 70% to 80% RH, addition of surfactants of all types causes deviations in growth factors of aqueous particles compared to those containing only NaCl. These deviations vary based on surfactant size and structure. Depending on the surfactant concentrations and types present in atmospheric aerosol particles, there may be deviations in the size and composition dependent growth factors of sea-spray aerosols from what current models represent.