In a search for a more effective solvent system than those discovered up to 1971 for separating the polycyclic hydrocarbon mixtures occurring in high-temperature tars, modifications were made to one found in 1957. Whatman No. 4 paper impregnated with 10% liquid paraffin solution in petrol ether was used as stationary phase, and methanol saturated with liquid paraffin as ascending mobile phase. Chromatography at 18° for 6 hr on 45×45 cm sheets of paper gave a separation considerably better than that achieved originally. Special attention was paid to the fraction containing carcinogenic hydrocarbons. No column chromatography or other pretreatment was necessary. Owing to the better separation it is possible to determine further polycyclic hydrocarbons such as 1,2, 5, 6-dibenzoanthracene, 3, 4, 9, 10-dibenzopyrene, and 3, 4, 8, 9-di-benzopyrene. A spot-evaluating procedure and a pretreatment of air samples have been developed. This procedure permits analysis of imponderable air samples.