Earth:Secondary organic aerosol
A secondary organic aerosol (SOA) is a molecule produced via oxidation over several generations of a parent organic molecule.[1] In contrast to primary organic aerosols, which are emitted directly from the biosphere, SOAs are either formed via homogeneous nucleation through the successive oxidation of gas-phase organic compounds, or through condensation on pre-existing particles. These gas-phase species exert high vapor pressures, meaning they are volatile and stable in the gas-phase.
Upon oxidation, the increased polarity, and thus reduced volatility, of the molecules results in a reduction of vapor pressure. After sufficient oxidation, the vapor pressure is sufficiently low that the gas-phase compound partitions into the solid-phase, producing secondary organic matter (the particle phase of SOA).
SOAs represent a significant proportion of aerosols contained in the troposphere.[1]
References
- ↑ 1.0 1.1 Yee, Lindsay D.; Craven, Jill S.; Loza, Christine L.; Schilling, Katherine A.; Ng, Nga Lee; Canagaratna, Manjula R.; Ziemann, Paul J.; Flagan, Richard C. et al. (2012-06-21). "Secondary Organic Aerosol Formation from Low-NOx Photooxidation of Dodecane: Evolution of Multigeneration Gas-Phase Chemistry and Aerosol Composition". The Journal of Physical Chemistry A 116 (24): 6211–6230. doi:10.1021/jp211531h. ISSN 1089-5639. PMID 22424261. Bibcode: 2012JPCA..116.6211Y. https://authors.library.caltech.edu/30169/2/jp211531h_si_001.pdf.
Bibliography
- Lewis, Alastair C. (2018). "The changing face of urban air pollution". Science 359 (6377): 744–745. doi:10.1126/science.aar4925. PMID 29449479. Bibcode: 2018Sci...359..744L. http://eprints.whiterose.ac.uk/127939/1/Science6377_Lewis.pdf.
- McDonald, Brian C.; De Gouw, Joost A.; Gilman, Jessica B.; Jathar, Shantanu H.; Akherati, Ali; Cappa, Christopher D.; Jimenez, Jose L.; Lee-Taylor, Julia et al. (2018). "Volatile chemical products emerging as largest petrochemical source of urban organic emissions". Science 359 (6377): 760–764. doi:10.1126/science.aaq0524. PMID 29449485. Bibcode: 2018Sci...359..760M.
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