AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Formation of Secondary Brown Carbon in the Multiphase Simulation Chamber (CESAM) through Aldehyde and Amine-Initiated Maillard Reactions
HANNAH G. WELSH, Raunak Pednekar, Elyse Pennington, Jason Casar, Lelia Hawkins, David De Haan, Aki Pajunoja, Jean-François Doussin, Mathieu Cazaunau, Edouard Pangui, Aline Gratien, Paola Formenti, Lorenzo Caponi, Harvey Mudd College
Abstract Number: 526 Working Group: Aerosol Chemistry
Abstract Laboratory measurements support the notion that secondary organic compounds-with absorbance spectra characteristic of atmospheric humic like substances (HULIS)-can form in aerosol and cloud water. Atmospheric HULIS encompass a wide range of properties with notable features such as broad, wavelength-dependent absorbance tailing into the visible region, highly functionalized and high molecular weight character, and, in some cases, appreciable organic nitrogen. In this work, we simulate the formation and evaporation of clouds in the presence of aldehydes and amines using a multiphase chamber designed for this purpose (Multiphase Atmospheric Experimental Simulation Chamber at the University of Paris Est Creteil, France). Particle absorbance was determined with a Particle Into Liquid Sampler-Capillary Waveguide system and was normalized to integrated particle mass measured with a scanning mobility particle sizer. Measurements indicate that browning occurs prior to cloud formation in the presence of methylamine and methylglyoxal but that browning increases following cloud formation. Further, artificial sunlight appears to bleach the products reducing overall aerosol absorbance. A second round of experiments conducted in summer 2016 provide more chemical detail and reproducibility of preliminary measurements.