TY - JOUR A1 - Novelli, Anna A1 - Kaminski, Martin A1 - Rolletter, Michael A1 - Acir, Ismail-Hakki A1 - Bohn, Birger A1 - Dorn, Hans-Peter A1 - Li, Xin A1 - Lutz, Anna A1 - Nehr, Sascha A1 - Rohrer, Franz A1 - Tillmann, Ralf A1 - Wegener, Robert A1 - Holland, Frank A1 - Hofzumahaus, Andreas A1 - Kiendler-Scharr, Astrid A1 - Wahner, Andreas A1 - Fuchs, Hendrik T1 - Evaluation of OH and HO2 concentrations and their budgets during photooxidation of 2-methyl-3-butene-2-ol (MBO) in the atmospheric simulation chamber SAPHIR T2 - Atmospheric Chemistry and Physics N2 - Several previous field studies have reported unexpectedly large concentrations of hydroxyl and hydroperoxyl radicals (OH and HO2, respectively) in forested environments that could not be explained by the traditional oxidation mechanisms that largely underestimated the observations. These environments were characterized by large concentrations of biogenic volatile organic compounds (BVOC) and low nitrogen oxide concentration. In isoprene-dominated environments, models developed to simulate atmospheric photochemistry generally underestimated the observed OH radical concentrations. In contrast, HO2 radical concentration showed large discrepancies with model simulations mainly in non-isoprene-dominated forested environments. An abundant BVOC emitted by lodgepole and ponderosa pines is 2-methyl-3-butene-2-ol (MBO), observed in large concentrations for studies where the HO2 concentration was poorly described by model simulations. In this work, the photooxidation of MBO by OH was investigated for NO concentrations lower than 200 pptv in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich. Measurements of OH and HO2 radicals, OH reactivity (kOH), MBO, OH precursors, and organic products (acetone and formaldehyde) were used to test our current understanding of the OH-oxidation mechanisms for MBO by comparing measurements with model calculations. All the measured trace gases agreed well with the model results (within 15 %) indicating a well understood mechanism for the MBO oxidation by OH. Therefore, the oxidation of MBO cannot contribute to reconciling the unexplained high OH and HO2 radical concentrations found in previous field studies. KW - Luftreinhaltung Y1 - 2018 UR - https://opus4.kobv.de/opus4-hs-duesseldorf/frontdoor/index/index/docId/4713 SN - 1680-7324 N1 - Code and data availability The data from the experiments in the SAPHIR chamber used in this work are available on the EUROCHAMP data home page (https://data.eurochamp.org/, last access: 1 October 2019, EUROCHAMP, 2019). Supplement The supplement related to this article is available online at: https://doi.org/10.5194/acp-20-3333-2020-supplement. VL - 18 IS - 15 SP - 11409 EP - 11422 PB - Copernicus ER -