Proximity Analysis Using GIS to Understand BTEX Exposure and Its Risk Assessment

Benzene, Toluene, Ethylbenzene and Xylene (BTEX) are non-methane hydrocarbons which are commonly found in urban environments and can be released into the air by motor vehicle traffic, petrol stations, and petrochemical industries. Exposure to BTEX compounds can cause both acute and chronic health effects. The most common sources of exposure to BTEX compounds are from breathing contaminated air, particularly in areas of heavy motor vehicle traffic and petrol stations. The proximity analysis and spatial variation of BTEX compounds were analysed for seven different sites in a metropolitan city in India using GIS and R software with the concentrations of pollutants collected from the CPCB monitoring stations. The GIS based pollution maps were plotted to understand the sources and highly sensitive areas in the region. The potential risk to the population were analysed using the variation map using IDW technique and population data at the locations. The concentrations of BTEX were high at locations of industrial operations and heavy traffic. The agglomeration of fuel stations contributed high concentrations of ethylbenzene and xylene during the summer and winter seasons in the area showing that the local activities contributed to the pollution in that region. The results indicated the count of population exposed to high concentrations and areas prone to high pollution levels. The study helps us to understand applicability of GIS in assessing the contributions of sources to pollution and their potential health risks to adjoining population.