Modeling Air Dispersion of Pollutants Emitted from the Daura Oil Refinery, Baghdad- Iraq using the CALPUFF Modeling System

Abstract

The CALPUFF atmospheric transport model was used to estimate ambient air concentrations of SO2, CO, NO2, and PM2.5, in a 256 km2 region surrounding the Daura oil refinery in Baghdad, Iraq during a six month period in the summer for 2013 and the winter of 2014. The CALPUFF modeling system includes a meteorological processor (CALMET), a Lagrangian puff atmospheric transport model (CALPUFF), and a post processor (CALPOST). Source term and meteorological data, including surface and upper air observations, were pre-processed and formatted for CALMET and CALPUFF using FORTRAN programs. Monthly emission rates and stack parameters for twelve stack sources were included in the model. Winds out of the northwest predominated, followed by winds out of the north and the west. The urban regions with the highest pollutant concentrations in the study domain were the Daura Express Highway located south and southeast of the facility, and the refinery employee residences located west of the facility. These areas were closest to the Daura oil refinery. Predicted pollutant concentrations showed that SO2 and CO were higher than NO2 and PM2.5, for the study period because emission rates of SO2 and CO were greater than NO2 and PM2.5. Monthly dispersion patterns were similar among the pollutants and exhibit plumes in the predominant wind direction. Winter generally had the highest predicted pollutant concentrations compared to the summer months.

Keywords: Daura refinery, CALPUFF, pollutant, dispersion, CALMET