10th International Aerosol Conference
September 2 - September 7, 2018
America's Center Convention Complex
St. Louis, Missouri, USA

Abstract View


Black Carbon Aerosol in a Clean Marine Environment

WALT WILLIAMS, Armin Sorooshian, Haflidi Jonsson, Richard Flagan, John Seinfeld, Andrew Metcalf, Clemson University

     Abstract Number: 1274
     Working Group: Carbonaceous Aerosol

Abstract
Black carbon (BC) aerosol was measured with a Single Particle Soot Photometer (SP2) in a relatively clean, marine environment in the Eastern Pacific, just off the central coast of California. In this region, direct emission of BC aerosol comes mostly from the shipping industry, with occasional inputs from biomass burning in California (although most emissions over land are carried eastward across the continental United States). Some BC aerosol in the region is from long-range transport from Asia. Regardless of BC source, the mixing state of individual BC aerosol particles can have a large effect on its climate-forcing potential and lifetime in the atmosphere. Recent results from other studies in remote marine environments show that some regions are characterized by uncoated BC, while other regions have nearly all BC aerosol mixed with water-soluble materials.

In this talk, measurements of BC mass, size distribution, concentration, and mixing state will be presented for a clean marine environment from 2 sampling campaigns: from summer of 2011 and summer of 2018. BC aerosol measurements will be compared to other measurements of total aerosol size, concentration, and chemical composition. One goal of this study is to use the BC mixing state information from the SP2 measurements to identify new emission sources of BC aerosol versus BC from long-range transport. To accomplish this goal, measurements from near-ship will be compared to those above the boundary layer to identify plume profiles from different aerosol sources. Another goal of this study to examine BC characteristics in droplet residual particles in relation to other inorganic and organic constituents. To accomplish this goal, some sampling periods were behind a counterflow virtual impactor. Finally, characteristics of long-term trends in BC aerosol in this region will be inferred from a comparison of these sampling campaigns 7 years apart.