Measurements on Stationary Source Emissions and Assessing Impact on Ambient Air Quality around Two Indian Refineries

Abstract

Emissions of particulate matter (PM), SO2 and NO2 from stationary sources and their concentration along with benzene and CO in ambient air around two Indian refineries were studied. Prediction of ground level concentration (GLC) of SO2, NO2 and PM was made by dispersion modeling. In Refinery 1, highest SO2 emission (646 mg Nm−3) were detected in Sulphur Recovery Unit while NOx emissions ranged from 57.8 to 445.0 mg Nm−3, respectively from various units. In Refinery 2, highest SO2 emission (935 mg Nm−3) was observed from Utility Boiler while NO2 emissions ranged from 13 to 235 mg Nm−3. Above emissions were within the stipulated emission standards prescribed by Central Pollution Control Board of India. Further, ambient concentrations of the above in the vicinity of these refineries were below their prescribed national ambient air quality standards. Air quality in terms of air quality index (AQI) was moderate or good at the study sites. Dispersion modelling exercise indicated that the observed GLC of SO2 and NO2 could be reasonably predicted by ISC-AERMOD model for both refineries while there was moderate to substantial difference between observed and modeled PM values due to presence of several sources of particulate emissions in the region that could not be considered in the model.