This part of ISO 16000 specifies sampling and preparation of sampling media for dioxin-like polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in indoor air (see Table C.1). The method incorporates a sampling procedure that collects PCBs and PCDFs/PCDDs from air on a fine-particle filter backed up by a sorbent trap. The method cannot be used to separately determine gaseous PCBs and PCDFs/PCDDs and those that are particle-associated because some of the compounds will volatilize from the filter and be collected by the sorbent trap. This part of ISO 16000 does not address analytical methods for PCBs PCDDs and PCDFs, which are included in ISO 16000-14. (ISO 16000-13 and ISO 16000-14 are both parts of the overall measurement procedure for the determination of PCBs and PCDDs/PCDFs.) Combined with the analytical procedures specified in ISO 16000-14, which incorporate specific analyses by high-resolution gas chromatography combined with high-resolution mass spectrometry (HRGC/HRMS), this method is capable of detecting 0,2 pg/m3 or lower concentrations of most PCBs and PCDFs/PCDDs. However, it may not be possible to detect all analytes at 0,2 pg/m3 or lower, especially at lower sampling rates. To achieve adequate detection limits, no less than 50 m3 of air should be sampled. For normal measurement tasks, sampling volumes up to 360 m3 are employed (equivalent to a sampling period of 24 h at 16 m3/h or 7 d at 2 m3/h). The method has been validated for sampling periods up to seven days. With the use of larger sorbent traps, sampling volumes up to 1 000 m3 have been validated. Sampling precision under normal conditions can be expected to be 25 % or better and uncertainty 50 % or better. If the appropriate restrictions are applied, this method can be used for small rooms, for example children’s rooms as well as for offices.