Long-term Trends of Atmospheric SO2, NO2 and O3 concentrations at South African INDAAF sites
Pieter G. van Zyl1, Jan-Stefan Swartz2, Johan Paul Beukes2, Corinne Galy-Lacaux3 and Kobus Pienaar2, (1)North-West University, Unit for Environmental Science and Management, Mahikeng, South Africa, (2)North-West University, Unit for Environmental Sciences and Management, Potchefstroom, South Africa, (3)University Paul Sabatier Toulouse III, Toulouse Cedex 09, France
