The contribution of gasoline to indoor air pollution in Tehran, Iran

Volatile organic compounds (VOCs) are released continuously into the indoor environment from a number of sources including building materials, furnishings and household products like air fresheners. In addition there are many activities carried out in houses that release VOCs intermittently. However, a major contributor to indoor pollution, particularly in large cities, is the outdoor environment largely through the concentration of vehicular traffic. In the present study, conducted in Tehran, the group of gasoline components commonly known as BTEX were measured as a surrogate for this pollution under different conditions in the indoor environment. Using a method published by NIOSH, organic vapours were collected by drawing air through charcoal-filled tubes with a portable pump with a flow rate of 0.2 m(3).min(-1). Organic material from the collected samples was eluted from the charcoal tubes by carbon disulphicle and the BTEX component analysed by Gas Chromatography. The results showed that proportionally high levels of BTEX were present in the VOC profile and it was concluded that petroleum and its combustion products were major contributors to indoor pollution in Tehran. Also, the concentration of benzene was especially high, being some 2-4 times greater than the maximum levels recommended by many countries.