Sndies 'j;owards Valxnated ! " G of Fcdds and Pcdfs in Stack Gas

Introduction Several procedures have been described for sampling stack gas of waste incineration f a c i l i t i e s for FCDDS/PCDFS* There have been discussions on whether comparable r e su l t s a r e obtained by d i f f e rent sampling methods and on how accurately t h e measured values correspond t o t h e actual PCDD/PCDF-concentrations i n t h e stack gas . Because there have been (unpublished) reports t h a t pa ra l l e l s amp l i n g by d i f fe ren t sampling procedures and subsequent analysis by d i f f e ren t laborator ies resulted i n PCDD/PCDF concentrations d i f f e r ing by a factor of 1 0 t o 50, Hagenmaier e t al. have carr ied out s tud ies on t h e comparison of various sampling methods (Hagenmaier e t al. 1985, 1986, 1987). I n these studies t h e following sampling procedures were compared: -/