Observational Investigation of BTEX Pollutant Concentration During Refueling Operations in the Air Inside Urban Stations of Hamadan

Fuel stations are one of the major sources of BTEX emissions to the atmosphere. Benzene, toluene, ethyl benzene and gazeline isomers are BTEX aromatic hydrocarbons. BTEX compounds are the most abundant volatile organic compounds in atmosphere and surface water.These compounds can affect the health of employees, drivers and surrounding residents. Due to the risks of BTEX compounds on people's health and the possibility of emitting them from fuel stations, examining the concentration of these compounds and controlling them in fuel stations is essential and effective in preventing their complications. The aim of this study is investigation the amount of BTEX in the ambient air of hamadan fuel stations and its surrounding and to compare with occupational and respiratory air standards.

The samples were collected according to the NIOSH method and the SKC adsorbent instruction by the individual sampling pump from indoor air and surrounding of Palestinian, Khansari and Forough fuel stations in Hamadan.The concentrationof BTEX compounds was extracted by dichrometan solvent and measured by GC/FID. The data were analyzed using SPSS software.

The mean of benzene, toluene, ethylenzene and xylene in Khansari fuel station were 1.23, 3.32, 0.31 and 1.43 mg/m3 respectively, in Palestine fuel station was 1.53, 4.14, 0.29 and 1.25 mg/m3 respectively and in Forough fuel station were 1.65, 2.23, 0.42 and 1.22 mg/m3, respectively. The highest concentration of BTEX compounds was located inside the fuel station and their concentration decreased by increasing the distance from the station. The mean concentrations of benzene in the air inside and distance 200m from the fuel stations were higher than EPA and in air inside and distance 50m from fuel station was higher than NIOSH guidelines. Also, the mean concentration of toluene in the air inside the Palestine fuel station was higher than the EPA guidelines.

The results showed that the dispersion of BTEX compounds in Hamadan refueling stations was caused by vehicles and gasoline evaporation during refueling. The reason for the decrease in the concentration of BTEX compounds by increasing the distance from fuel stations can be attributed to the production of pollutant concentrations in the yard stations, temperature conditions, wind direction and vehicles transportation. By increasing the distance from the station, as the production resources are more inside the station, from the concentration of BTEX compounds decreases by increasing the distance. Also, by increasing the distance from station, the wind airflow, lead to the distribution and dispersion of BTEX compounds and decreases its concentration. Employed personnel and drivers inside fuel stationsare confronted with benzene and toluene pollutants. As regards to short-term counterview with BTEX compounds causes effects such as stimulation and sensitivity of the skin, central nervous system problems (fatigue, headache, dizziness and loss of balance). Also in long-term encounters, in addition to the problems mentioned, they can affect the kidney, liver and blood. Therefore, more oversight should be carried out by petroleum product authorities and control actions to maintain the health of the people and reduce the pollutants in fuel stations, including leakage of tanks and pumps, and the possibility of recycling of gasoline vapors during refueling.