10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Measuring the Physical Properties of Refractory Black Carbon off the Los Angeles Coast
JOSEPH KO, Trevor Krasowsky, George Ban-Weiss, University of Southern California
Abstract Number: 1681 Working Group: Carbonaceous Aerosol
Abstract Black carbon (BC) is widely known to impact the radiative balance of the atmosphere, subsequently playing a role in global climate. The physical properties of refractory black carbon (rBC) were measured using a single particle soot photometer (SP2) on Catalina Island between September 7 and September 14, 2017. Catalina Island is located off the coast of Southern California, approximately 22 miles southwest of the Port of Los Angeles. The mass concentration, number concentration, and coating thickness was analyzed in conjunction with local/regional meteorology to characterize rBC properties for different meteorological regimes in this semi-remote sampling location. The campaign-averaged mass and number concentrations were 0.04 μg/m3 and 20 cm-3, respectively. This is approximately an order of magnitude lower than what has been observed in recent studies for the Los Angeles basin. Using the leading-edge-only technique, we found that approximately 27% (±19%) of rBC particles were thickly-coated, which is close to the lower end of values from past aircraft measurements in Los Angeles and the upper end of previous ground measurements in Los Angeles. HYSPLIT back-trajectory analyses were used for approximate source characterization. Many large fires in the Pacific Northwest were coincidentally active during the time of the sampling campaign, and preliminary back-trajectories show a high probability of impact from these biomass-burning events. The potential for spikes in rBC measurements due to passing cargo ships is also assessed.