Toluene as an indicator of vehicular exhaust: Impact on Air Quality - Case Study

Background: According to the World Health Organization (WHO)1 , toluene (C6H5CH3) is a Volatile Organic Compound (VOC) that is believed to be the most abundant hydrocarbon in the troposphere. Sources of anthropogenic toluene emissions include catalytic conversion of petroleum and chemical production facilities; but, vehicle exhaust was considered to be the dominant source. The adverse health effects of human exposure to toluene include dysfunction of the Central Nervous System, kidney failure and reproductive abnormalities including spontaneous abortion among pregnant women. As a result, the California Occupational Safety and Health Administration (CalOSHA) has set a Permissible Exposure Limit (PEL) of 10 ppm (Time Weighted Average) for toluene.