| Title: | An amorphous solid state of biogenic secondary organic aerosol particles |
| Author(s): | Virtanen A; Joutsensaari J; Koop T; Kannosto J; Yli-Pirila P; Leskinen J; Makela JM; Holopainen JK; Poschl U; Kulmala M; Worsnop DR; Laaksonen A; |
| Address: | "Department of Physics, Tampere University of Technology, P O Box 692, 33101 Tampere, Finland. annele.virtanen@tut.fi" |
| ISSN/ISBN: | 1476-4687 (Electronic) 0028-0836 (Linking) |
| Abstract: | "Secondary organic aerosol (SOA) particles are formed in the atmosphere from condensable oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs). On a global scale, biogenic VOCs account for about 90% of VOC emissions and of SOA formation (90 billion kilograms of carbon per year). SOA particles can scatter radiation and act as cloud condensation or ice nuclei, and thereby influence the Earth's radiation balance and climate. They consist of a myriad of different compounds with varying physicochemical properties, and little information is available on the phase state of SOA particles. Gas-particle partitioning models usually assume that SOA particles are liquid, but here we present experimental evidence that they can be solid under ambient conditions. We investigated biogenic SOA particles formed from oxidation products of VOCs in plant chamber experiments and in boreal forests within a few hours after atmospheric nucleation events. On the basis of observed particle bouncing in an aerosol impactor and of electron microscopy we conclude that biogenic SOA particles can adopt an amorphous solid-most probably glassy-state. This amorphous solid state should provoke a rethinking of SOA processes because it may influence the partitioning of semi-volatile compounds, reduce the rate of heterogeneous chemical reactions, affect the particles' ability to accommodate water and act as cloud condensation or ice nuclei, and change the atmospheric lifetime of the particles. Thus, the results of this study challenge traditional views of the kinetics and thermodynamics of SOA formation and transformation in the atmosphere and their implications for air quality and climate" |
| Keywords: | "Aerosols/*chemistry/*metabolism Atmosphere/*chemistry Gases/chemistry/metabolism Human Activities Kinetics Microscopy, Electron Particle Size Particulate Matter/*chemistry/*metabolism Plants/*metabolism Thermodynamics Volatile Organic Compounds/chemistry/;" |
| Notes: | "MedlineVirtanen, Annele Joutsensaari, Jorma Koop, Thomas Kannosto, Jonna Yli-Pirila, Pasi Leskinen, Jani Makela, Jyrki M Holopainen, Jarmo K Poschl, Ulrich Kulmala, Markku Worsnop, Douglas R Laaksonen, Ari eng Research Support, Non-U.S. Gov't England 2010/10/15 Nature. 2010 Oct 14; 467(7317):824-7. doi: 10.1038/nature09455" |
