Risk assessment of benzene in ambient air of Delhi

Globally different countries in the world use environmental risk assessment as a tool to evaluate the toxicity of a pollutant in the environment. Health risk assessment is done to evaluate the possible adverse health effects of benzene on human health. The concentration of benzene was measured at two locations in Delhi, a global city, during 2011-2015.The cancer risk in ambient air of Delhi was calculated at CEXPavg, CEXP50, and CEX90. From the year 2011 to 2015 at CEXPavg and CEXP50 cancer risk varies from 1.71 to 9.26 per 106 and at CEXP90 cancer risk varies from 3.9 to 24.12 per 106 which were higher in comparison with mean and median concentrations. The cancer risk calculated in this study is comparable with the studies conducted in Kolkata, India and few other European countries. The annual average exposure concentration of benzene ranges from 3.02 µg/m3 in 2015 to 16.3 µg/m3 in 2011.The mean value found in 2015 was less than National Ambient Air Quality Standards (NAAQS) of benzene i.e. 5µg/m3.Our study revealed that there is a decrease in the level of benzene from 2011 to 2015 at two locations in Delhi which may be attributed to the implementation of Auto Fuel Policy 2003, by the Government in reducing benzene contents in the gasoline from the source and subsequent environmental measures in Delhi.