Air pollution is a global phenomenon as a major problem. World Health Organization estimated 500,000 deaths annually as a result of air pollution. Air pollution models are strong tools for studying both the dispersion and concentration of the pollutants. AERMOD is one of the preffered software by the US Environmental Protection Agency (EPA). In this study, the dispersion of CO and NOx releaed from Dorahan Gas Compressor station in Borujen, Charmahal and Bakhtyari Province as well as nearby roads (Borujen - Lordegan road) are simulated by AERMOD software in an area of approximately 110 Km 2 . The simulation is done for 1-hour, 8-hours, seasonal and annual intervals. Dorahan Gas Compressor Station supplies the pressure needed to transfer gas from west to the north of the country. There three turbins as Turbin No.1 with 10 MW, Turbin No.2 with 28 MW and Turbin No.3 with 24.5 MW power. The hourly meteorological data from 01 May 2013 to 31 March 2014 were taken in this study. Traffic load of the road is as 507 light vehicles and 107 heavy vehicles (Trucks, Trailers, buses and Mini-buses). The results showed that the air pollution dispersed in the most part of the studied area is caused by Dorahan Gas Compressor station, and the pollution by road traffic is trivial. Maximum CO concentration simulated in 8-hours intervals, and that of NOx in annual intervals for Dorahan Gas Compressor station and nearby roads are 22.47 and 3.15 µg/m 3 , respectively, which both did not exceed the Clean Air Standards. Keywords: Air pollution modeling, AERMOD, CO, NOx, Gas Compressor station.
