IDENTIFYING THE CONTRIBUTING SOURCES OF PCDDs/PCDFs BY COMPARISON OF CONGENER DISTRIBUTION PROFILES OBSERVED IN RESPIRABLE SUSPENDED PARTICULATE MATTER SAMPLED FROM AMBIENT AIR OF DELHI

摘要

PCDDs/PCDFs (17 congeners) are regularly being monitored in the respirable suspended particulate matter from ambient air at several locations of Delhi, consequently significant amount of data has been generated. This baseline data has been used for identification of emission sources releasing these compounds into ambient air by comparing the average congener profiles (percent ratio of individual concentration of 2,3,7,8 substituted congeners to the total concentration of 2,3,7,8 substituted congeners) from each location with congener profiles for various specific emission sources available in literature. It is observed from the comparison of congener profiles from each location with source specific congener profiles that the impact of thermal power plants and medical / hospital waste incinerator is dominant on surrounding locations nearby these sources respectively. The locations farther from these major sources are found to have impact of local industrial units burning various fuels and probably mixed industrial wastes, however, the contribution of automobiles sources can be attributed to all locations in metropolitan city Delhi. For conclusive identification of various sources of PCDDs/PCDFs, further studies would be undertaken for establishing source specific congener profiles, including more locations as possible receptors for specific source categories and including congeners other than 2,3,7,8-substituted congeners.