AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Identifying the Main Sources of Brown Carbon in the Atmosphere
IMAD EL HADDAD, Nivedita Kumar, Joel Corbin, Kaspar Rudolf Daellenbach, Dario Massabò, Emily Bruns, Athanasia Vlachou, Carlo Bozzetti, Jay Slowik, Paolo Prati, Urs Baltensperger, Jean-Luc Jaffrezo, Luka Drinovec, Grisa Mocnik, Martin Gysel, Andre Prévôt, Paul Scherrer Institute
Abstract Number: 299 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Atmospheric brown carbon (BrC) contributes significantly to aerosol absorption in the atmosphere, especially at lower wavelengths. This fraction of the organic aerosol is composed of a large number of complex chromophores. The main processes by which these compounds are introduced in the atmosphere or formed through atmospheric oxidation remain virtually unknown and, as a result, the contribution of BrC to atmospheric absorption is highly uncertain. Here, using factorization techniques, we combine offline aerosol mass spectrometry and light absorption measurements to identify the main primary and secondary sources of BrC, at two contrasted urban sites in Switzerland over a yearly cycle. We determine that biomass burning is the major source of BrC at both sites, with humic-like substances contributing greatly to this absorption. Through complementary smog chamber experiments, we investigate the optical properties of biomass burning emissions as a function of aging.