Polychlorobenzene (PCB) contents in the exhausted gas from garbage combustion and in the air were measured. For the former, the exhaust gas was sucked from the duct directly by a pump and passed through two mist traps which were maintained at 0 and -78 C and through an n-hexane trap at -78 C. The PCB in the three traps was pooled and n-hexane was separated from water by a fractionating funnel and then concentrated by a KD concentrator, purified by fluorigel column, and finally analyzed by gas chromatography quantitatively and qualitatively. Air was sucked by high volume air sampler for 24 hr and dust collected on filter paper was extracted into 100 ml of n-hexane for 4 or 5 hr. This was concentrated by KD concentrator to 5 ml and analyzed by gas chromatography after purification by fluorigel column.