Hydrogen peroxide, organic peroxides, carbonyl compounds, and organic acids measured at Pabstthum during BERLIOZ

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Read Full Article (file size: 1474452 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D4, 8250, doi:10.1029/2001JD001096, 2003 Hydrogen peroxide, organic peroxides, carbonyl compounds, and organic acids measured at Pabstthum during BERLIOZ D. Grossmann Division of Atmospheric Chemistry, Max-Planck-Institut für Chemie, Mainz, Germany G. K. Moortgat Division of Atmospheric Chemistry, Max-Planck-Institut für Chemie, Mainz, Germany M. Kibler Chemistry Department, Technische Universität Darmstadt, Darmstadt, Germany S. Schlomski Chemistry Department, Technische Universität Darmstadt, Darmstadt, Germany K. Bächmann Chemistry Department, Technische Universität Darmstadt, Darmstadt, Germany B. Alicke Institut für Umweltphysik, University of Heidelberg, Heidelberg, Germany A. Geyer Institut für Umweltphysik, University of Heidelberg, Heidelberg, Germany U. Platt Institut für Umweltphysik, University of Heidelberg, Heidelberg, Germany M.-U. Hammer Institut für Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe/Universität Karlsruhe (TH), Karlsruhe, Germany B. Vogel Institut für Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe/Universität Karlsruhe (TH), Karlsruhe, Germany D. Mihelcic Institut für Chemie und Dynamik der Geosphäre, Forschungszentrum Jülich, Jülich, Germany A. Hofzumahaus Institut für Chemie und Dynamik der Geosphäre, Forschungszentrum Jülich, Jülich, Germany F. Holland Institut für Chemie und Dynamik der Geosphäre, Forschungszentrum Jülich, Jülich, Germany A. Volz-Thomas Institut für Chemie und Dynamik der Geosphäre, Forschungszentrum Jülich, Jülich, Germany Abstract Gas-phase H₂O₂, organic peroxides, carbonyl compounds, and carboxylic acids were measured from mid-July to early August 1998 during the Berlin ozone (BERLIOZ) campaign in Pabstthum, Germany. The rural site, located 50 km northwest from Berlin, was chosen to measure the pollutants downwind during a summer smog episode. The hydroperoxides showed pronounced diurnal variations with peak mixing ratios in the early afternoon. The maximum mixing ratios were 1.4 ppbv (H₂O₂), 0.64 ppbv (methylhydroperoxide), and 0.22 ppbv (hydroxymethyl-hydroperoxide). H₂O₂ was formed through photochemical activity, but originated also from vertical transport from air residing above the local inversion layer in the morning hours. Sometimes a second maximum was observed in the late afternoon-evening: This H₂O₂ might be formed from ozonolysis of biogenic alkenes. Ratios of H₂O₂/HNO₃ were used as indicators for the determination of NO_x-sensitive versus volatile organic compound (VOC)-sensitive regimes for photochemical production of ozone. Diurnal profiles were measured for alkanals (C₂–C₁₀), showing maximum mixing ratios decreased from C₂ (0.6 ppbv) to C₅ (0.1 ppbv) alkanals, which originate primarily from anthropogenic hydrocarbon degradation processes. However, higher C₆, C₉, and C₁₀ alkanals show strong fluctuations (0.25, 0.17, and 0.13 ppbv, respectively), showing evidence of biogenic emissions. Both primary unsaturated carbonyl (methyl vinyl ketone, methacrolein) and secondary oxidation products of isoprene (hydroxyacetone and glycolaldehyde, up to 0.16 and 0.20 ppbv, respectively) showed excellent correlation. Diurnal profiles of glyoxal, methylglyoxal, biacetyl, benzaldehyde, and pinonaldehyde were also obtained. Formaldehyde was measured continuously by long-path DOAS and by an instrument based on the “Hantzsch” reaction; however, mixing ratios measured by DOAS (maximum 7.7 ppbv) were systematically larger by a factor of 1.3 on average, but by a factor of 1.7 during high photochemical activity. Homologous series of monocarboxylic acids were determined: Formic and acetic acid varied between 0.6 and 3.0 ppbv. The mixing ratio of the other dropped from 0.1 to 0.2 ppbv for C₃ to typical 0.01 to 0.03 ppbv for C₆, and from 0.01 to 0.002 ppbv for C₇ to C₉ monocarboxylic acids. Published 29 January 2003. Index Terms: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry. Read Full Article (file size: 1474452 bytes) Cited by Citation: Grossmann, D., et al. (2003), Hydrogen peroxide, organic peroxides, carbonyl compounds, and organic acids measured at Pabstthum during BERLIOZ, J. Geophys. Res., 108(D4), 8250, doi:10.1029/2001JD001096. Copyright 2003 by the American Geophysical Union.

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