Hygroscopic growth of size-resolved, emission-source classified, aerosol particles sampled across the United States

Wednesday, 17 December 2014
Taylor Shingler1, Ewan COLIN Crosbie1, Luke D Ziemba2, Bruce E Anderson2, Pedro Campuzano Jost3, Jose L Jimenez3, Tomas Mikoviny4, Armin Wisthaler4 and Armin Sorooshian1, (1)University of Arizona, Tucson, AZ, United States, (2)NASA Langley Research Center, Hampton, VA, United States, (3)University of Colorado at Boulder, Boulder, CO, United States, (4)University of Oslo, Oslo, Norway
The hygroscopic growth of atmospheric aerosol particles is a key air quality parameter, impacting the radiation budget, visibility, and cloud formation. During the DC3 and SEAC4RS field campaigns (>300 total flight hours), measurements were made over 32 US states, Canada, the Pacific Ocean, and the Gulf of Mexico, between the surface and 41,000 feet ASL. The aircraft research payloads included a suite of in-situ aerosol and gas phase instruments. The Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe (DASH-SP) and the Langley Aerosol Research Group Experiment (LARGE) humidified nephelometer instrument applied different techniques to measure water uptake by aerosol particles at prescribed relative humidity values. Size-resolved growth factor (GF ≡ Dp,wet/Dp,dry) measurements by the DASH-SP are compared to bulk scattering measurements (f(RH) ≡ σscat,wetscat,dry) by the LARGE instrument. Spatial location and volatile organic compound tracers such as isoprene and acetonitrile are used to classify the origin of distinct air masses, including: forest fires, biogenic-emitting forests, agricultural use lands, marine boundary layer, urban, and rural background. Analyses of GF results by air mass origin are reported and results are compared with f(RH) measurements. A parameterization between the f(RH) and GF measurements and its potential uses are discussed.