Secondary organic aerosol (SOA) formation through isoprene oxidation was investigated with the regional-scale climate model REMOTE. The applied modeling scheme includes a treatment for marine primary organic aerosol emissions, aerosol microphysics, and SOA formation through the gas/particle partitioning of semivolatile, water-soluble oxidation products. The focus was on SOA formation taking place over the North-East Atlantic during a period of high biological activity. Isoprene SOA concentrations were up to ~5？ng over North Atlantic in the base case model runs, and isoprene oxidation made a negligible contribution to the marine organic aerosol (OA) mass. In particular, isoprene SOA did not account for the observed water-soluble organic carbon (WSOC) concentrations over North Atlantic. The performed model calculations, together with results from recent field measurements, imply a missing source of SOA over remote marine areas unless the isoprene oxidation products are considerably less volatile than the current knowledge indicates. 1. Introduction Marine aerosols influence the global climate system directly by scattering incoming solar radiation and indirectly by acting as nuclei on which cloud droplets are formed [1, 2]. The magnitude of these effects depend on both the physical and chemical properties of marine aerosols. These properties are tied to the aerosol formation mechanisms which can be classified as primary, such as mechanical production driven by wind interactions at the ocean surface, and secondary which refers to gas-to-particle conversion (including heterogeneous reactions) resulting from the gas phase oxidation of volatile compounds [3]. Recently, considerable research effort has been put into characterizing the contribution of organic compounds to the marine aerosol [4–6]. The research has been motivated by the work of O'Dowd et al. [7] who found significant amounts of both water soluble and water insoluble organic aerosol mass in clean marine air. However, the sources of organic carbon are not fully characterized at the present and hence also the relative contributions of primary and secondary processes remain to be evaluated. In this regard, it has been suggested that a potentially important aerosol source is the formation of secondary organic aerosol (SOA) via isoprene oxidation [8]. Several studies have investigated the importance of the SOA formation to the marine aerosol by employing modeling and remote sensing techniques along with laboratory measurements [9–11]. Meskhidze and Nenes [9] suggested that SOA formation resulting from
References
[1]
S. Twomey, “Aerosols, clouds and radiation,” Atmospheric Environment, Part A, vol. 25, no. 11, pp. 2435–2442, 1991.
[2]
U. Lohmann and J. Feichter, “Global indirect aerosol effects: a review,” Atmospheric Chemistry and Physics, vol. 5, no. 3, pp. 715–737, 2005.
[3]
C. D. O'Dowd and G. De Leeuw, “Marine aerosol production: a review of the current knowledge,” Philosophical Transactions of the Royal Society A, vol. 365, no. 1856, pp. 1753–1774, 2007.
[4]
F. Cavalli, M. C. Facchini, and M. C. Facchini, “Advances in characterization of size-resolved organic matter in marine aerosol over the North Atlantic,” Journal of Geophysical Research D, vol. 109, no. 24, Article ID D24215, 14 pages, 2004.
[5]
Y. J. Yoon, D. Ceburnis, and D. Ceburnis, “Seasonal characteristics of the physicochemical properties of North Atlantic marine atmospheric aerosols,” Journal of Geophysical Research D, vol. 112, no. 4, Article ID D04206, 2007.
[6]
M. C. Facchini, M. Rinaldi, and M. Rinaldi, “Primary submicron marine aerosol dominated by insoluble organic colloids and aggregates,” Geophysical Research Letters, vol. 35, no. 17, Article ID L17814, 2008.
[7]
C. D. O'Dowd, M. C. Facchini, and M. C. Facchini, “Biogenically driven organic contribution to marine aerosol,” Nature, vol. 431, no. 7009, pp. 676–680, 2004.
[8]
A. G. Carlton, C. Wiedinmyer, and J. H. Kroll, “A review of Secondary Organic Aerosol (SOA) formation from isoprene,” Atmospheric Chemistry and Physics, vol. 9, no. 14, pp. 4987–5005, 2009.
[9]
N. Meskhidze and A. Nenes, “Phytoplankton and cloudiness in the southern ocean,” Science, vol. 314, no. 5804, pp. 1419–1423, 2006.
[10]
S. R. Arnold, D. V. Spracklen, and D. V. Spracklen, “Evaluation of the global oceanic isoprene source and its impacts on marine organic carbon aerosol,” Atmospheric Chemistry and Physics, vol. 9, no. 4, pp. 1253–1262, 2009.
[11]
B. Gantt, N. Meskhidze, and D. Kamykowski, “A new physically-based quantification of marine isoprene and primary organic aerosol emissions,” Atmospheric Chemistry and Physics, vol. 9, no. 14, pp. 4915–4927, 2009.
[12]
B. Langmann, “Numerical modelling of regional scale transport and photochemistry directly together with meteorological processes,” Atmospheric Environment, vol. 34, no. 21, pp. 3585–3598, 2000.
[13]
B. Langmann, S. Varghese, E. Marmer, E. Vignati, J. Wilson, P. Stier, and C. O'Dowd, “Aerosol distribution over Europe: a model evaluation study with detailed aerosol microphysics,” Atmospheric Chemistry and Physics, vol. 8, no. 6, pp. 1591–1607, 2008.
[14]
E. Roeckner, K. Arpe, L. Bengtsson, et al., “The atmospheric general circulation model ECHAM-4: model description and simulation of present-day climate,” Tech. Rep. 218, Max Planck Institute for Meteorology, Hamburg, Germany, 1996.
[15]
E. Vignati, J. Wilson, and P. Stier, “M7: an efficient size-resolved aerosol microphysics module for large-scale aerosol transport models,” Journal of Geophysical Research D, vol. 109, no. 22, Article ID D22202, 17 pages, 2004.
[16]
P. Stier, J. Feichter, and J. Feichter, “The aerosol-climate model ECHAM5-HAM,” Atmospheric Chemistry and Physics, vol. 5, no. 4, pp. 1125–1156, 2005.
[17]
E. Vignati, M. C. Facchini, and M. C. Facchini, “Global scale emission and distribution of sea-spray aerosol: sea-salt and organic enrichment,” Atmospheric Environment, vol. 44, no. 5, pp. 670–677, 2010.
[18]
P. I. Palmer and S. L. Shaw, “Quantifying global marine isoprene fluxes using MODIS chlorophyll observations,” Geophysical Research Letters, vol. 32, no. 9, Article ID GL022592, 5 pages, 2005.
[19]
J. H. Seinfeld and S. N. Pandis, Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, John Wiley & Sons, New York, NY, USA, 1998.
[20]
J. A. Dean, Lange’s Handbook on Chemistry, McGraw-Hill, New York, NY, USA, 13th edition, 1985.
[21]
P. Saxena and L. M. Hildemann, “Water-soluble organics in atmospheric particles: a critical review of the literature and application of thermodynamics to identify candidate compounds,” Journal of Atmospheric Chemistry, vol. 24, no. 1, pp. 57–109, 1996.
[22]
M. Claeys, B. Graham, and B. Graham, “Formation of secondary organic aerosols through photooxidation of isoprene,” Science, vol. 303, no. 5661, pp. 1173–1176, 2004.
[23]
E. O. Edney, T. E. Kleindienst, M. Jaoui, M. Lewandowski, J. H. Offenberg, W. Wang, and M. Claeys, “Formation of 2-methyl tetrols and 2-methylglyceric acid in secondary organic aerosol from laboratory irradiated isoprene/ / /air mixtures and their detection in ambient samples collected in the eastern United States,” Atmospheric Environment, vol. 39, no. 29, pp. 5281–5289, 2005.
[24]
I. Kourtchev, T. Ruuskanen, W. Maenhaut, M. Kulmala, and M. Claeys, “Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyyti？l？, Finland,” Atmospheric Chemistry and Physics, vol. 5, no. 10, pp. 2761–2770, 2005.
[25]
J. F. Pankow, “An absorption model of the gas/aerosol partitioning involved in the formation of secondary organic aerosol,” Atmospheric Environment, vol. 28, no. 2, pp. 189–193, 1994.
[26]
C. Marcolli and T. Peter, “Water activity in polyol/water systems: new UNIFAC parameterization,” Atmospheric Chemistry and Physics, vol. 5, no. 6, pp. 1545–1555, 2005.
[27]
B. J. Turpin and H.-J. Lim, “Species contributions to PM2.5 mass concentrations: revisiting common assumptions for estimating organic mass,” Aerosol Science and Technology, vol. 35, no. 1, pp. 602–610, 2001.
[28]
D. Ceburnis, C. D. O'Dowd, and C. D. O'Dowd, “Marine aerosol chemistry gradients: elucidating primary and secondary processes and fluxes,” Geophysical Research Letters, vol. 35, no. 7, Article ID L07804, 2008.
[29]
H.-J. Lim, A. G. Carlton, and B. J. Turpin, “Isoprene forms secondary organic aerosol through cloud processing: model simulations,” Environmental Science and Technology, vol. 39, no. 12, pp. 4441–4446, 2005.
[30]
A. Limbeck, M. Kulmala, and H. Puxbaum, “Secondary organic aerosol formation in the atmosphere via heterogeneous reaction of gaseous isoprene on acidic particles,” Geophysical Research Letters, vol. 30, no. 19, Article ID GL017738, 6 pages, 2003.
[31]
N. Yassaa, I. Peeken, E. Z？llner, K. Bluhm, S. Arnold, D. Spracklen, and J. Williams, “Evidence for marine production of monoterpenes,” Environmental Chemistry, vol. 5, no. 6, pp. 391–401, 2008.
