Benzene in Gasoline

The TLV for gasoline as calculated by ACGIH guidelines places emphasis on aromatic hydrocarbon content. Because of its volatility, desirable front-end performance characteristics yet low TLV (10 ppm), benzene is the most important aromatic component in gasoline. Because of differences in processing, European gasolines often have higher benzene content than U.S. gasolines. This study of one company's U.S. and European gasolines in both liquid and vapor phases demonstrates that a much lower level of benezene vapor in air is produced than commonly believed. Benzene concentrations in air remained relatively constant under varying conditions and did not increase as the gasoline continued to evaporate. A nomograph is presented which allows prediction of benzene concentration in air from the concentration found in the liquid phase.