Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 8 16 2008 10.5194/acp-8-4823-2008 http://www.atmos-chem-phys.net/8/4823/2008/ http://www.atmos-chem-phys.net/8/4823/2008/acp-8-4823-2008.html http://www.atmos-chem-phys.net/8/4823/2008/acp-8-4823-2008.pdf 4823 4839 2008-08-19 Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment L. Laakso lauri.laakso@iki.fi H. Laakso P. P. Aalto P. Keronen T. Petäjä T. Nieminen T. Pohja E. Siivola M. Kulmala N. Kgabi M. Molefe D. Mabaso D. Phalatse K. Pienaar V.-M. Kerminen Department of Physical Sciences, University of Helsinki, P. O. BOX 64, 00014 Helsinki, Finland Earth and Sun Systems Laboratory, Atmospheric Chemistry Division, Nat. Center for Atmospheric Res., Boulder, CO, USA Department of Physics, North-West University, Private Bag X 2046, Mmabatho, South Africa Department of Biology, North-West University, Private Bag X 2046, Mmabatho, South Africa School of Chemistry, North-West University, Private Bag X 6001, Potchefstroom, South Africa Finnish Meteorological Institute, P.O. Box 503, 00101 Helsinki, Finland We have analyzed one year (July 2006–July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations were equal to 0.7 ppb for SO2, 1.4 ppb for NOx, 36 ppb for O3 and 105 ppb for CO. The corresponding PM1, PM2.5 and PM10 concentrations were 9.0, 10.5 and 18.8 μg m−3, and the annual median total particle number concentration in the size range 10–840 nm was 2340 cm−3. 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