ACP Atmospheric Chemistry and Physics ACP Atmos. Chem. Phys. 1680-7324 Copernicus Publications Göttingen, Germany 10.5194/acp-11-7301-2011 Secondary organic aerosol formation from the photooxidation of isoprene, 1,3-butadiene, and 2,3-dimethyl-1,3-butadiene under high NO<sub>x</sub> conditions Sato K. 1 2 4 Nakao S. 1 3 Clark C. H. 1 3 Qi L. 1 3 Cocker III D. R. 1 3 Bourns College of Engineering – Center for Environmental Research & Technology, University of California, Riverside, 1084 Columbia Ave., Riverside, CA 92507, USA Asian Environment Research Group, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA now at: Center for Regional Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan 25 07 2011 11 14 7301 7317 Copyright: © 2011 K. Sato et al. 2011 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://acp.copernicus.org/articles/11/7301/2011/acp-11-7301-2011.html The full text article is available as a PDF file from https://acp.copernicus.org/articles/11/7301/2011/acp-11-7301-2011.pdf

Secondary organic aerosol (SOA) formation from atmospheric oxidation of isoprene has been the subject of multiple studies in recent years; however, reactions of other conjugated dienes emitted from anthropogenic sources remain poorly understood. SOA formation from the photooxidation of isoprene, isoprene-1-<sup>13</sup>C, 1,3-butadiene, and 2,3-dimethyl-1,3-butadiene is investigated for high NO<sub>x</sub> conditions. The SOA yield measured in the 1,3-butadiene/NO<sub>x</sub>/H<sub>2</sub>O<sub>2</sub> irradiation system (0.089–0.178) was close to or slightly higher than that measured with isoprene under similar NO<sub>x</sub> conditions (0.077–0.103), suggesting that the photooxidation of 1,3-butadiene is a possible source of SOA in urban air. In contrast, a very small amount of SOA particles was produced in experiments with 2,3-dimethyl-1,3-butadiene. Off-line liquid chromatography – mass spectrometry analysis revealed that the signals of oligoesters comprise a major fraction (0.10–0.33) of the signals of the SOA products observed from all dienes investigated. The oligoesters originate from the unsaturated aldehyde gas phase diene reaction products; namely, semi-volatile compounds produced by the oxidation of the unsaturated aldehyde undergo particle-phase oligoester formation. Oligoesters produced by the dehydration reaction between nitrooxypolyol and 2-methylglyceric acid monomer or its oligomer were also characterized in these experiments with isoprene as the starting diene. These oligomers are possible sources of the 2-methyltetrols found in ambient aerosol samples collected under high NO<sub>x</sub> conditions. Furthermore, in low-temperature experiments also conducted in this study, the SOA yield measured with isoprene at 278 K was 2–3 times as high as that measured at 300 K under similar concentration conditions. Although oligomerization plays an important role in SOA formation from isoprene photooxidation, the observed temperature dependence of SOA yield is largely explained by gas/particle partitioning of semi-volatile compounds.

 References Agrawal, H., Welch, W. A., Miller, J. W., and Cocker, D. R.: Emission measurements from a crude oil tanker at sea, Environ. Sci. Technol., 42, 7098–7103, 2008. An, W. J., Pathak, R. K., Lee, B.-H., and Pandis, S. N.: Aerosol volatility measurement using an improved thermodenuder: Application to secondary organic aerosol, J. Aerosol Sci., 38, 305–314, 2007. Angove, D. E., Fookes, C. J. R., Hynes, R. G., Walters, C. K., and Azzi, M.: The characterization of secondary organic aerosol formed during the photodecomposition of 1,3-butadiene in air containing nitric oxide, Atmos. Enviorn., 40, 4597–4607, 2006. Atkinson, R.: Kinetics and mechanisms of gas-phase reactions of the hydroxyl radical with organic compounds under atmospheric conditions, Chem. Rev., 86, 69–201, 1986. Böge, O., Miao, Y., Plewka, A., and Herrmann, H.: Formation of secondary organic particle phase compounds from isoprene gas-phase oxidation products: An aerosol chamber and field study, Atmos. Environ., 40, 2501–2509, 2006. Bowman, F. M., Odum, J. R., Seinfeld, J. H., and Pandis, S. N.: Mathematical model for gas-particle partitioning of secondary organic aerosols, Atmos. Environ., 31, 3921–3931, 1997. Calvert, J. G., Atkinson, R., Becker, K. H., Kamens, R. M., Seinfeld, J. H., Wallington, T. J., and Yarwood, G.: Importance of aromatic hydrocarbons in the chemistry of ozone generation in the urban atmosphere, in: The Mechanisms of Atmospheric Oxidation of Aromatic Hydrocarbons, Oxford University Press, New York, USA, 3–35, 2002. Carlton, A. G., Lim, H.-J., Altieri, K., Seitinger, S., and Turpin, B. J.: Link between isoprene and SOA: fate of pyruvic acid in dilute aqueous solution, Geophys. Res. Lett., 33, L06822, <a href="http://dx.doi.org/10.1029/2005GL025374">https://doi.org/10.1029/2005GL025374</a>, 2006. Carlton, A. G., Wiedinmyer, C., and Kroll, J. H.: A review of Secondary Organic Aerosol (SOA) formation from isoprene, Atmos. Chem. Phys., 9, 4987–5005, <a href="http://dx.doi.org/10.5194/acp-9-4987-2009">https://doi.org/10.5194/acp-9-4987-2009</a>, 2009. Carter, W. P. L., Cocker&nbsp;III, D. R., Fitz, D. R., Malkina, I. L., Bumiller, K., Sauer, C. G., Pisano, J. T., Bufalino, C., and Song, C.: A new environmental chamber for evaluation of gas-phase chemical mechanisms and secondary organic aerosol formation, Atmos. Environ., 39, 7768–7788, 2005. Chan, A. W. H., Kroll, J. H., Ng, N. L., and Seinfeld, J. H.: Kinetic modeling of secondary organic aerosol formation: effects of particle- and gas-phase reactions of semivolatile products, Atmos. Chem. Phys., 7, 4135–4147, <a href="http://dx.doi.org/10.5194/acp-7-4135-2007">https://doi.org/10.5194/acp-7-4135-2007</a>, 2007. Chan, A. W. H., Chan, M. N., Surratt, J. D., Chhabra, P. S., Loza, C. L., Crounse, J. D., Yee, L. D., Flagan, R. C., Wennberg, P. O., and Seinfeld, J. H.: Role of aldehyde chemistry and NO<sub>x</sub> concentrations in secondary organic aerosol formation, Atmos. Chem. Phys., 10, 7169–7188, <a href="http://dx.doi.org/10.5194/acp-10-7169-2010">https://doi.org/10.5194/acp-10-7169-2010</a>, 2010. Chen, X. H., Hulbert, D., and Shepson, P. B.: Measurement of the organic nitrate yield from OH reaction with isoprene, J. Geophys. Res., 103, 25563–25568, 1998. Claeys, M., Graham, B., Vas, G., Wang, W., Vermeylen, R., Pashynska, V., Cafmeyer, J., Guyon, P., Andreae, M. O., Artaxo, P., and Maenhaut, W.: Formation of secondary organic aerosols through photooxidation of isoprene, Science, 303, 1173-1176, 2004a. Claeys, M., Wang, W., Ion, A. C., Kourtchev, I., Gelencsér, A., and Maenhaut, W.: Formation of secondary organic aerosols from isoprene and its gas-phase oxidation products through reaction with hydrogen peroxide, Atmos. Environ., 38, 4093–4098, 2004b. Claeys, M., Kourtchev, I., Pashynska, V., Vas, G., Vermeylen, R., Wang, W., Cafmeyer, J., Chi, X., Artaxo, P., Andreae, M. O., and Maenhaut, W.: Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC~2002 biomass burning experiment in Rondônia, Brazil: sources and source processes, time series, diel variations and size distributions, Atmos. Chem. Phys., 10, 9319–9331, http://dx.doi.org/10.5194/acp-10-9319-2010https://doi.org/10.5194/acp-10-9319-2010, 2010. Clements, A. and Seinfeld, J. H.: Detection and quantification of 2-methyltetrols in ambient aerosol in the southeastern United States, Atmos. Environ., 41, 1825–1830, 2007. Cocker&nbsp;III, D. R., Flagan, R. C., and Seinfeld, J. H.: State-of-the-art chamber facility for studying atmospheric aerosol chemistry, Environ. Sci. Technol., 35, 2594–2601, 2001. Darer, A. I., Cole-Filipiak, N. C., O'Connor, A. E., and Elrod, M. J.: Formation and stability of atmospherically relevant isoprene-derived organosulfates and organonitrates, Environ. Sci. Technol., 45, 1895–1902, 2011. DeMore, W. B., Sander, S. P., Golden, D. M., Hampson, R. F., Kurylo, M. J., Howerd, C. J., Ravishankara, A. R., Kolb, C. E., and Molina, M. J.: Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling, JPL Publication&nbsp;97-4, NASA Jet Propulsion Laboratory, Pasadena, USA, 1997. Dommen, J., Metzger, A., Duplissy, J., Kalberer, M., Alfarra, M. R., Gascho, A., Weingartner, E., Prevot, A. S. H., Verheggen, B., and Baltensperger, U.: Laboratory observation of oligomers in the aerosol from isoprene/NO<sub>x</sub> photooxidation, Geophys. Res. Lett., 33, L13805, <a href="http://dx.doi.org/10.1029/2006GL026523">https://doi.org/10.1029/2006GL026523</a>, 2006. Drewnick, F., Hings, S. S., DeCarlo, P. F., Jayne, J. T., Gonin, M., Fuhrer, K., Weimer, S., Jimenez, J. L., Demerjian, K. L., Borrmann, S., and Worsnop, D. R.: A new time-of-flight aerosol mass spectrometer (ToF-AMS) – instrument description and first field deployment, Aerosol Sci. Tech., 39, 637-658, 2005. Edney, E. O., Kleindienst, T. E., Jaoui, M., Lewandowski, M., Offenberg, J. H., Wang, W., and Claeys, M.: Formation of 2-methyl tetrols and 2-methylglyceric acid in secondary organic aerosol from laboratory irradiated isoprene/NO<sub>x</sub>/SO<sub>2</sub>/air mixtures and their detection in ambient PM<sub>2.5</sub> samples collected in the eastern United States, Atmos. Enviorn., 39, 5281–5289, 2005. Fu, P. Q., Kawamura, K., Chen, J., and Barrie, L. A.: Isoprene, monoterpene, and sesquiterpene oxidation products in the high arctic aerosols during late winter to early summer, Environ. Sci. Technol., 43, 4022–4028, 2009. Fu, P. Q., Kawamura, K., Kanaya, Y., and Wang, Z.: Contributions of biogenic volatile organic compounds to the formation of secondary organic aerosols over Mt.&nbsp;Tai, Central East China, Atmos. Environ., 44, 4817–4826, 2010a. Fu, P. Q., Kawamura, K., Pavuluri, C. M., Swaminathan, T., and Chen, J.: Molecular characterization of urban organic aerosol in tropical India: contributions of primary emissions and secondary photooxidation, Atmos. Chem. Phys., 10, 2663–2689, <a href="http://dx.doi.org/10.5194/acp-10-2663-2010">https://doi.org/10.5194/acp-10-2663-2010</a>, 2010b. Gómez-González, Y., Surratt, J. D., Cuyckens, F., Szmigielski, R., Vermeylen, R., Jaoui, M., Lewandowski, M., Offenberg, J. H., Kleindienst, T. E., Edney, E. O., Blockhuys, F., Van Alsenoy, C., Maenhaut, W., and Claeys, M.: Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/(-)electrospray ionization mass spectrometry, J. Mass Spectrom., 43, 371–382, 2008. Guenther, A., Karl, T., Harley, P., Wiedinmyer, C., Palmer, P. I., and Geron, C.: Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature), Atmos. Chem. Phys., 6, 3181–3210, <a href="http://dx.doi.org/10.5194/acp-6-3181-2006">https://doi.org/10.5194/acp-6-3181-2006</a>, 2006. Hallquist, M., Wenger, J. C., Baltensperger, U., Rudich, Y., Simpson, D., Claeys, M., Dommen, J., Donahue, N. M., George, C., Goldstein, A. H., Hamilton, J. F., Herrmann, H., Hoffmann, T., Iinuma, Y., Jang, M., Jenkin, M. E., Jimenez, J. L., Kiendler-Scharr, A., Maenhaut, W., McFiggans, G., Mentel, Th. F., Monod, A., Prévôt, A. S. H., Seinfeld, J. H., Surratt, J. D., Szmigielski, R., and Wildt, J.: The formation, properties and impact of secondary organic aerosol: current and emerging issues, Atmos. Chem. Phys., 9, 5155–5236, <a href="http://dx.doi.org/10.5194/acp-9-5155-2009">https://doi.org/10.5194/acp-9-5155-2009</a>, 2009. Hatakeyama, S., Tanonaka, T., Weng, J. H., Bandow, H., Takagi, H., and Akimoto, H.: Ozone cyclohexene reaction in air-quantitative analysis of particulate products and the reaction mechanism, Environ. Sci. Technol., 19, 935–942, 1985. Henze, D. K. and Seinfeld, J. H.: Global secondary organic aerosol from isoprene oxidation, Geophys. Res. Lett., 33, L09812, <a href="http://dx.doi.org/10.1029/2006GL025976">https://doi.org/10.1029/2006GL025976</a>, 2006. Henze, D. K., Seinfeld, J. H., Ng, N. L., Kroll, J. H., Fu, T.-M., Jacob, D. J., and Heald, C. L.: Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs. low-yield pathways, Atmos. Chem. Phys., 8, 2405–2420, <a href="http://dx.doi.org/10.5194/acp-8-2405-2008">https://doi.org/10.5194/acp-8-2405-2008</a>, 2008. Jang, M. and Kamens, R. M.: Characterization of secondary aerosol from the photooxidation of toluene in the presence of NO<sub>x</sub> and 1-propene, Environ. Sci. Technol., 35, 3626–3639, 2001. Jang, M., Czoschke, N. M., Lee, S., and Kamens, R. M.: Heterogeneous atmospheric aerosol production by acid-catalyzed particle-phase reactions, Science, 298, 814–817, 2002. Jeffries, H. E.: Photochemical air pollution, in: Composition, Chemistry, and Climate of the Atmosphere, Van Nostrand Reinhold, New York, USA, 308–348, 1995. Jemma, C. A., Shore, P. R., and Widdicombe, K. A.: Analysis of C<sub>1</sub>-C<sub>16</sub> hydrocarbons using dual-column capillary GC: Application to exhaust emissions from passenger car and motorcycle engines, J. Chromatogr. Sci., 33, 34–48, 1995. Kleindienst, T. E., Lewandowski, M. L., Offenberg, J. H., Jaoui, M., and Edney, E. O.: Ozone-isoprene reaction: Re-examination of the formation of secondary organic aerosol, Geophys. Res. Lett., 34, L01805, <a href="http://dx.doi.org/10.1029/2006GL027485">https://doi.org/10.1029/2006GL027485</a>, 2007. Kleindienst, T. E., Lewandowski, M., Offenberg, J. H., Jaoui, M., and Edney, E. O.: The formation of secondary organic aerosol from the isoprene + OH reaction in the absence of NO<sub>x</sub>, Atmos. Chem. Phys., 9, 6541–6558, <a href="http://dx.doi.org/10.5194/acp-9-6541-2009">https://doi.org/10.5194/acp-9-6541-2009</a>, 2009. Kroll, J. H. and Seinfeld, J. H.: Chemistry of secondary organic aerosol: formation and evolution of low-volatility organics in the atmosphere, Atmos. Environ., 42, 3593–3624, 2008. Kroll, J. H., Ng, N. L., Murphy, S. M., Flagan, R. C., and Seinfeld, J. H.: Secondary organic aerosol formation from isoprene photooxidation under high-NO<sub>x</sub> conditions, Geophys. Res. Lett., 32, L18808, <a href="http://dx.doi.org/10.1029/2005GL023637">https://doi.org/10.1029/2005GL023637</a>, 2005. Kroll, J. H., Ng, N. L., Murphy, S. M., Flagan, R. C., and Seinfeld, J. H.: Secondary organic aerosol formation from isoprene photooxidation, Environ. Sci. Technol., 40, 1869–1877, 2006. Liu, Y., Shao, M., Fu, L., Lu, S., Zeng, L., and Tang, D.: Source profiles of volatile organic compounds (VOCs) measured in China: Part&nbsp;I, Atmos. Environ., 42, 6247–6260, 2008. Lockwood, A. L., Shepson, P. B., Fiddler, M. N., and Alaghmand, M.: Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry, Atmos. Chem. Phys., 10, 6169–6178, <a href="http://dx.doi.org/10.5194/acp-10-6169-2010">https://doi.org/10.5194/acp-10-6169-2010</a>, 2010. Malloy, Q. G. J., Li Qi, Warren, B., Cocker&nbsp;III, D. R., Erupe, M. E., and Silva, P. J.: Secondary organic aerosol formation from primary aliphatic amines with NO<sub>3</sub> radical, Atmos. Chem. Phys., 9, 2051–2060, <a href="http://dx.doi.org/10.5194/acp-9-2051-2009">https://doi.org/10.5194/acp-9-2051-2009</a>, 2009. Miyoshi, A., Hatakeyama, S., and Washida, N.: OH radical-initiated photooxidation of isoprene: an estimate of global CO production, J. Geophys. Res., 99, 18779–18787, 1994. Nelson, P. F., Tibbett, A. R., and Day, S. J.: Effects of vehicle type and fuel quality on real world toxic emissions from diesel vehicles, Atmos. Environ., 42, 5291–5303, 2008. Ng, N. L., Kwan, A. J., Surratt, J. D., Chan, A. W. H., Chhabra, P. S., Sorooshian, A., Pye, H. O. T., Crounse, J. D., Wennberg, P. O., Flagan, R. C., and Seinfeld, J. H.: Secondary organic aerosol (SOA) formation from reaction of isoprene with nitrate radicals (NO<sub>3</sub>), Atmos. Chem. Phys., 8, 4117–4140, <a href="http://dx.doi.org/10.5194/acp-8-4117-2008">https://doi.org/10.5194/acp-8-4117-2008</a>, 2008. Odum, J. R., Hoffmann, T., Bowman, F., Collins, D., Flagan, R. C., and Seinfeld, J. H.: Gas/particle partitioning and secondary organic aerosol yields, Environ. Sci. Technol., 30, 2580–2585, 1996. Pandis, S. N., Paulson, S. E., Seinfeld, J. H., and Flagan, R. C.: Aerosol formation in the photooxidation of isoprene and β-pinene, Atmos. Environ., 25A, 997–1008, 1991. Paulot, F., Crounse, J. D., Kjaergaard, H. G., Kürten, A., St.&nbsp;Clair, J. M., Seinfeld, J. H., and Wennberg, P. O.: Unexpected epoxide formation in the gas-phase photooxidation of isoprene, Science, 325, 730–733, 2009. Qi, L., Nakao, S., Tang, P., and Cocker&nbsp;III, D. R.: Temperature effect on physical and chemical properties of secondary organic aerosol from <i>m</i>-xylene photooxidation, Atmos. Chem. Phys., 10, 3847–3854, <a href="http://dx.doi.org/10.5194/acp-10-3847-2010">https://doi.org/10.5194/acp-10-3847-2010</a>, 2010. Rollins, A. W., Kiendler-Scharr, A., Fry, J. L., Brauers, T., Brown, S. S., Dorn, H.-P., Dubé, W. P., Fuchs, H., Mensah, A., Mentel, T. F., Rohrer, F., Tillmann, R., Wegener, R., Wooldridge, P. J., and Cohen, R. C.: Isoprene oxidation by nitrate radical: alkyl nitrate and secondary organic aerosol yields, Atmos. Chem. Phys., 9, 6685–6703, <a href="http://dx.doi.org/10.5194/acp-9-6685-2009">https://doi.org/10.5194/acp-9-6685-2009</a>, 2009. Sato, K.: Detection of nitrooxypolyols in secondary organic aerosol formed from the photooxidation of conjugated dienes under high-NO<sub>x</sub> conditions, Atmos. Environ., 42, 6851–6861, 2008. Sato, K., Klotz, B, Hatakeyama, S., Imamura, T., Washizu, Y., Matsumi, Y., and Washida, N.: Secondary organic aerosol formation during the photo-oxidation of toluene: dependence on initial hydrocarbon concentration, Bull. Chem. Soc. Jpn., 77, 667–671, 2004. Sato, K., Takami, A., Isozaki, T., Hikida, T., Shimono, A., and Imamura, T.: Mass spectrometric study of secondary organic aerosol formed from the photo-oxidation of aromatic hydrocarbons, Atmos. Environ., 44, 1080–1087, 2010. Shi, J. P. and Harrison, R. M.: Rapid NO<sub>2</sub> formation in diluted petrol-fuelled engine exhaust – A source of NO<sub>2</sub> in winter smog episodes, Atmos. Environ., 31, 3857–3866, 1997. Smith, D., Cheng, P., and Spanel, P.: Analysis of petrol and diesel vapour and vehicle engine exhaust gases using selected ion flow tube mass spectrometry, Rapid Commun. Mass Sp., 16, 1124–1134, 2002. Surratt, J. D., Murphy, S. M., Kroll, J. H., Ng, N. L., Hildebrandt, L., Sorooshian, A., Szmigielski, R., Vermeylen, R., Maenhaut, W., Claeys, M., Flagan, R. C., and Seinfeld, J. H.: Chemical composition of secondary organic aerosol formed from the photooxidation of isoprene, J. Phys. Chem.&nbsp;A, 110, 9665–9690, 2006. Surratt, J. D., Lewandowski, M., Offenberg, J. H., Jaoui, M., Kleindienst, T. E., Edney, E. O., and Seinfeld, J. H.: Effect of acidity on secondary organic aerosol formation from isoprene, Environ. Sci. Technol., 41, 5363–5369, 2007. Surratt, J. D., Gómez-González, Y., Chan, A. W. H., Vermeylen, R., Shahgholi, M., Kleindienst, T. E., Edney, E. O., Offenberg, J. H., Lewandowski, M., Jaoui, M., Maenhaut, W., Claeys, M., Flagan, R. C., and Seinfeld, J. H.: Organosulfate formation in biogenic secondary organic aerosol, J. Phys. Chem.&nbsp;A., 112, 8345–8378, 2008. Surratt, J. D., Chan, A. W. H., Eddingsaas, N. C., Chan, M. N., Loza, C. L., Kwan, A. J., Hersey, S. P., Flagan, R. C., Wennberg, P. O., and Seinfeld, J. H.: Reactive intermediates revealed in secondary organic aerosol formation from isoprene, P. Natl. Acad. Sci. USA, 1007, 6640–6645, 2010. Szmigielski, R., Surratt, J. D., Vermeylen, R., Szmigielska, K., Kroll, J. H., Ng, N. L., Murphy, S. M., Sorooshian, A., Seinfeld, J. H., and Claeys, M.: Characterization of 2-methylglyceric acid oligomers in secondary organic aerosol formed from the photooxidation of isoprene using trimethylsilylation and gas chromatography/ion trap mass spectrometry, J. Mass. Spectrom., 42, 101–116, 2007. Szmigielski, R., Dommen, J., Metzger, A., Maenhaut, W., Baltensperger, U., and Claeys, M.: The acid effect in the formation of 2-methyltetrols from the photooxidation of isoprene in the presence of NO<sub>x</sub>, Atmos. Res., 98, 183–189, 2010. Takekawa, H., Minoura, H., and Yamazaki, S.: Temperature dependence of secondary organic aerosol formation by photo-oxidation of hydrocarbons, Atmos. Environ., 37, 3413–3424, 2003. ToF-AMS Software Downloads: <a href="http://cires.colorado.edu/jimenez-group/ToFAMSResources/">http://cires.colorado.edu/jimenez-group/ToFAMSResources/</a> (last access: 12&nbsp;January&nbsp;2010), 2009. Treacy, J., El Hag, M., O'Farrell, D., and Sidebottom, H.: Reactions of ozone with unsaturated organic compounds, Ber. Bunsenges. Phys. Chem., 96, 422–427, 1992. Wang, W., Kourtchev, I., Graham, B., Cafmeyer, J., Maenhaut, W., and Claeys, M.: Characterization of oxygenated derivatives of isoprene related to 2-methyltetrols in Amazonian aerosols using trimethylsilylation and gas chromatography/ion trap mass spectrometry, Rapid Commun. Mass Spectrom., 19, 1343–1351, 2005. Xia, X. and Hopke, P. K.: Seasonal variation of 2-methyltetrols in ambient air samples, Environ. Sci. Technol., 40, 6934–6937, 2006. Yokouchi, Y.: Seasonal and diurnal-variation of isoprene and its reaction-products in a semirural area, Atmos. Environ., 28, 2651–2658, 1994.