Assessing the effect of marine isoprene and ship emissions on ozone, using modelling and measurements from the South Atlantic OceanJ. Williams A K , T. Custer A , H. Riede A , R. Sander A , P. Jöckel A , P. Hoor A , A. Pozzer A B , S. Wong-Zehnpfennig A , Z. Hosaynali Beygi A , H. Fischer A , V. Gros C , A. Colomb D , B. Bonsang C , N. Yassaa A E , I. Peeken F G , E. L. Atlas H , C. M. Waluda I , J. A. van Aardenne J and J. Lelieveld A
A Max Planck Institute for Chemistry, J. J. Becherweg 27, D-55128 Mainz, Germany.
B Energy, Environment and Water Research Center of the Cyprus Institute, 1645 Nicosia, Cyprus.
C Laboratoire des Sciences du Climat et de l’Environnement, Commissariat à l’Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), F-91191 Gif sur Yvette, France.
D Laboratoire Interuniversitaire des Systèmes Atmosphériques, Unité Mixte de Recherche (UMR) 7583/CNRS, Université Paris 12, 61 av. Général de Gaulle, F-94010 Créteil, France.
E Present address: Faculty of Chemistry, University of Sciences and Technologie Houari Boumediene, University of Sciences and Technology Houari Boumediene (USTHB), B.P. 32 El-Alia, Bab-Ezzouar, 16111 Algiers, Algeria.
F Alfred Wegener Institute for Polar and Marine Research, Polar Biological Oceanography Am Handelshafen 12, D-27570 Bremerhaven, Germany.
G Present address: Center for Marine Environmental Sciences (MARUM), Leobener Strasse, D-28359 Bremen, Germany.
H Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA.
I Biological Sciences Division, British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK.
J European Commission, Institute for Environment and Sustainability, I-21020 Ispra, Italy.
K Corresponding author. Email: email@example.com
Environmental Chemistry 7(2) 171-182 http://dx.doi.org/10.1071/EN09154
Submitted: 27 November 2009 Accepted: 17 February 2010 Published: 22 April 2010
Environmental context. Air over the remote Southern Atlantic Ocean is amongst the cleanest anywhere on the planet. Yet in summer a large-scale natural phytoplankton bloom emits numerous natural reactive compounds into the overlying air. The productive waters also support a large squid fishing fleet, which emits significant amounts of NO and NO2. The combination of these natural and man-made emissions can efficiently produce ozone, an important atmospheric oxidant.
Abstract. Ship-borne measurements have been made in air over the remote South Atlantic and Southern Oceans in January–March 2007. This cruise encountered a large-scale natural phytoplankton bloom emitting reactive hydrocarbons (e.g. isoprene); and a high seas squid fishing fleet emitting NOx (NO and NO2). Using an atmospheric chemistry box model constrained by in-situ measurements, it is shown that enhanced ozone production ensues from such juxtaposed marine biogenic and anthropogenic emissions. The relative impact of shipping and phytoplankton emissions on ozone was examined on a global scale using the EMAC model. Ozone in the marine boundary layer was found to be over ten times more sensitive to NOx emissions from ships, than to marine isoprene in the region south of 45°. Although marine isoprene emissions make little impact on the global ozone budget, co-located ship and phytoplankton emissions may explain the increasing ozone reported for the 40–60°S southern Atlantic region.