The measurement method described in this guideline serves the establishment of the concentrations of dioxin- like PCBs (non-ortho PCB 77, 81, 126, 169; mono-ortho PCB 105, 114, 118, 123, 156, 157, 167, 189) in ambient air and in indoor air. With a view to the determination of the WHO toxicity equivalents, the method described can also be implemented for measurement of dioxins together with PCBs. Joint sampling is thus possible.