Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 12645-12658, 2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
25 Oct 2017
Summertime OH reactivity from a receptor coastal site in the Mediterranean Basin
Nora Zannoni1,a, Valerie Gros1, Roland Sarda Esteve1, Cerise Kalogridis1,2, Vincent Michoud3,4, Sebastien Dusanter3, Stephane Sauvage3, Nadine Locoge3, Aurelie Colomb5, and Bernard Bonsang1 1LSCE, Laboratorie Scientifique du Climat et de l'Environnement, CNRS-CEA-UVSQ, IPSL, Université Paris-Saclay, 91191 Gif sur Yvette, France
2Institute of Nuclear Technology and Radiation Protection, National Centre of Scientific Research “Demokritos”, 15310 Ag. Paraskevi, Attiki, Greece
3IMT Lille Douai, Univ. Lille, SAGE – Département Sciences de l'Atmosphère et Génie de l'Environnement, 59000 Lille, France
4Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS – UMR7583, Université Paris-Est-Créteil et Université Paris Diderot, Institut Pierre Simon Laplace, Créteil, France
5LAMP, Campus universitaire des Cezeaux, 4 Avenue Blaise Pascal, 63178 Aubiere, France
anow at: Air chemistry department, Max Planck Institute for Chemistry, Mainz, Germany
Abstract. Total hydroxyl radical (OH) reactivity, the total loss frequency of the hydroxyl radical in ambient air, provides the total loading of OH reactants in air. We measured the total OH reactivity for the first time during summertime at a coastal receptor site located in the western Mediterranean Basin. Measurements were performed at a temporary field site located in the northern cape of Corsica (France), during summer 2013 for the project CARBOSOR (CARBOn within continental pollution plumes: SOurces and Reactivity)–ChArMEx (Chemistry and Aerosols Mediterranean Experiment). Here, we compare the measured total OH reactivity with the OH reactivity calculated from the measured reactive gases. The difference between these two parameters is termed missing OH reactivity, i.e., the fraction of OH reactivity not explained by the measured compounds. The total OH reactivity at the site varied between the instrumental LoD (limit of detection  =  3 s−1) to a maximum of 17 ± 6 s−1 (35 % uncertainty) and was 5 ± 4 s−1 (1σ SD – standard deviation) on average. It varied with air temperature exhibiting a diurnal profile comparable to the reactivity calculated from the concentration of the biogenic volatile organic compounds measured at the site. For part of the campaign, 56 % of OH reactivity was unexplained by the measured OH reactants (missing reactivity). We suggest that oxidation products of biogenic gas precursors were among the contributors to missing OH reactivity.

Citation: Zannoni, N., Gros, V., Sarda Esteve, R., Kalogridis, C., Michoud, V., Dusanter, S., Sauvage, S., Locoge, N., Colomb, A., and Bonsang, B.: Summertime OH reactivity from a receptor coastal site in the Mediterranean Basin, Atmos. Chem. Phys., 17, 12645-12658,, 2017.
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Short summary
Our paper presents results of hydroxyl radical (OH) reactivity from a field study conducted during summer 2013 in a western Mediterranean coastal site (Corsica, France). Here, the total OH reactivity, measured with the comparative reactivity method, is compared with the summed OH reactivity from the reactive gases measured with a multitude of different technologies. Our results demonstrate the relatively high observed reactivity and the large impact of biogenic compounds.
Our paper presents results of hydroxyl radical (OH) reactivity from a field study conducted...