AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Effect of Chemical Structure on the Rapid Formation of Extremely Low Volatility Organic Compounds from BVOC Oxidation
MIKKO SIPILÄ, Tuija Jokinen, Torsten Berndt, Mikael Ehn, Heikki Junninen, Pauli Paasonen, Stefanie Richters, Frank Stratmann, Hartmut Herrmann, Douglas Worsnop, Markku Kulmala, Veli-Matti Kerminen, University of Helsinki
Abstract Number: 182 Working Group: Advances in the Physics and Chemistry of New Particle Formation and Growth
Abstract Oxidation products of terpenes and isoprene have a major influence on the global secondary organic aerosol burden, and atmospheric nanoparticle and cloud condensation nuclei (CCN) production. Here we draw special attention to the formation of highly oxidized, extremely low volatility organic compounds (ELVOC), from ozonolysis and OH radical oxidation of series of biogenic volatile organic compounds (BVOC) including terpenes and isoprene. We show that ELVOC from these precursors can be formed promptly after the initial attack of an oxidant via formation of RO2 radical and successive intramolecular hydrogen shifts followed by a rapid reaction with oxygen (O2). We demonstrate how the structure of the VOC and the initial oxidation reaction affects the formation of ELVOC. Investigated BVOC include compounds with endocyclic double bond (such as alpha-pinene and limonene), exocyclic double bond (e.g. beta-pinene) and acyclic compounds (e.g. myrcene or isoprene). Formation of ELVOC can result in CCN formation, while the formation of higher volatility oxidation products could potentially even inhibit CCN production. This feature would be due to the preferential partitioning of higher-volatility species into larger, already CCN-sized particles which increases condensation and coagulation sinks. These results advance understanding of observations in environments with different biogenic emission patterns and oxidation conditions. The results also provide new guidance for developing large-scale modeling frameworks that simulate current or future biosphere-atmosphere-climate interactions.