In November 1989 the Polish government and the German government signed a bilateral agreement on scientific and technological co-operation. In the framework of this co-operation the Central Laboratory for Radiological Protection (Centralne Laboratorium Ochrony Radiologicznej, CLOR), Warsaw, the company Physik-Technik-Innovation (PTI), Erlangen, and the Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, conducted a co-operation project in the field of monitoring of the airborne radioactivity in ground level air. This progress report deals with the history, the scientific activities and the results of the project covering the period from July 1993 to December 1998. weiterlesen