Benzene toluene and xylene in exhaust from gasoline automobiles

Abstract

The exhaust emissions of the air toxic benzene, toluene and xylene from catalytic and non-catalytic equipped gasoline automobiles have been measured in the idle condition. The exhaust gas samples from tailpipe were collected by Tedlar bag in the vacuum box. The automobile samples were classified into 4 different groups as follow: 1. New catalytic car (less than 5 years old), 2. Moderate age catalytic car (5-10 years old), 3. Moderate age non-catalytic car (5-10 years old) and 4. Old non-catalytic car (more than 10 years old). The highest concentration was found in the old non-catalytic car group. The average concentrations of benzene, toluene and xylene in old non-catalytic cars group were 12.11 ppm, 33.88 ppm and 8.55 ppm respectively. While the lowest concentrations of air toxic were found in the new catalytic cars group. Besides, the ratio of benzene, toluene and xylene in gasoline and exhaust were 1:5.76:1.5 and 1:1.92:0.55, respectively. The statistical t-test was used to determine the relationship between the catalytic converter and vehicle emission. The results from SPSS programming showed that there was no significant difference of pollutants emitted among car with and without catalytic converter at significant level (alpha) 0.05. It was also found that the age of engine has a strong influence on concentration of pollutants in vehicle exhaust.