| Title: | Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation |
| Author(s): | Shiraiwa M; Yee LD; Schilling KA; Loza CL; Craven JS; Zuend A; Ziemann PJ; Seinfeld JH; |
| Address: | "Divisions of Chemistry and Chemical Engineering and Engineering, California Institute of Technology, Pasadena, CA 91125, USA" |
| ISSN/ISBN: | 1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking) |
| Abstract: | "Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process" |
| Keywords: | "Aerosols/*chemistry Aldehydes/chemistry Alkanes/chemistry Atmosphere/*analysis Carbon/analysis Kinetics *Models, Chemical Oxidation-Reduction Oxygen/analysis Particle Size Photochemistry Volatile Organic Compounds/*chemistry alkane gas-particle interactio;" |
| Notes: | "MedlineShiraiwa, Manabu Yee, Lindsay D Schilling, Katherine A Loza, Christine L Craven, Jill S Zuend, Andreas Ziemann, Paul J Seinfeld, John H eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2013/07/03 Proc Natl Acad Sci U S A. 2013 Jul 16; 110(29):11746-50. doi: 10.1073/pnas.1307501110. Epub 2013 Jul 1" |
