Leibniz-Institut für Troposphärenforschung (TROPOS), Permoserstrasse 15, D-04318 Leipzig, Germany
Peter van Velthoven
Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, NL-3730 AE De Bilt, The Netherlands
David Oram
National Centre for Atmospheric Science, University of East Anglia (UEA), Norwich NR4 7TJ, UK
Debbie O'Sullivan
National Centre for Atmospheric Science, University of East Anglia (UEA), Norwich NR4 7TJ, UK
Christoph Dyroff
Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
Andreas Zahn
Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
Helmut Ziereis
Institut für Physik der Atmosphäre, Deutsches Zentrum für Luft- und Raumfahrt (DLR), D-82230 Wessling, Germany
Tropospheric sections of flights with the CARIBIC (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrumented Container) observatory from May 2005 until June 2013, are investigated for the occurrence of plumes with elevated Hg concentrations. Additional information on CO, CO2, CH4, NOy, O3, hydrocarbons, halocarbons, acetone and acetonitrile enable us to attribute the plumes to biomass burning, urban/industrial sources or a mixture of both. Altogether, 98 pollution plumes with elevated Hg concentrations and CO mixing ratios were encountered, and the Hg/CO emission ratios for 49 of them could be calculated. Most of the plumes were found over East Asia, in the African equatorial region, over South America and over Pakistan and India. The plumes encountered over equatorial Africa and over South America originate predominantly from biomass burning, as evidenced by the low Hg/CO emission ratios and elevated mixing ratios of acetonitrile, CH3Cl and particle concentrations. The backward trajectories point to the regions around the Rift Valley and the Amazon Basin, with its outskirts, as the source areas. The plumes encountered over East Asia and over Pakistan and India are predominantly of urban/industrial origin, sometimes mixed with products of biomass/biofuel burning. Backward trajectories point mostly to source areas in China and northern India. The Hg/CO2 and Hg/CH4 emission ratios for several plumes are also presented and discussed.