AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Multi-Wavelength Measurements of Soot Optical Properties Using CAPS PMssa and CRD-PAS Instruments
Sara Forestieri, Andrew Lambe, Molly Cummings, James Brogan, Christopher Cappa, Paul Davidovits, ANDREW FREEDMAN, Timothy Onasch, Aerodyne Research, Inc.
Abstract Number: 306 Working Group: Instrumentation and Methods
Abstract We have obtained measurements of light absorption, scattering and extinction coefficients and thus single scattering albedo (SSA) of soot particles produced using an inverted diffusion flame and a premixed flat burner flame operating with methane and ethylene fuels, respectively. Extinction and absorption were measured at 405 nm and 532 nm using a dual cavity ringdown photoacoustic spectrometer (CRD-PAS; UC Davis). Scattering and extinction were measured at 630 nm using a CAPS PMssa single scattering albedo monitor (Aerodyne). Soot particle mass was quantified using a centrifugal particle mass analyzer (CPMA; Cambustion), mobility size with a scanning mobility particle sizer (SMPS; TSI) and soot number concentration with a mixing condensational particle counter (MCPC; BMI). The wavelength dependent, mass-specific optical properties were measured for denuded soot particles as a function of particle mobility size and as a function of non-absorbing coatings (dioctyl sebacate and sulfuric acid). The measured mass specific absorption coefficient at 405 nm for denuded soot is substantially higher than that reported by Radney, et al. [Environ. Sci. Tech., 48:3169–3176 (2014)] even after accounting for differences in soot chemical composition.