Yafteh

Background: With regard to application of the oil fuel at winter in Dorud cement plant, the aim of this study was to investigaten NO_X, SO₂ and particulate matter (PM) dispersion from cement plant stack at downwind direction and atmospheric different conditions and thermal inversion in winter season up to distance 5000 m from emission source and its comparison with clean air and NAAQS standard.

Materials and Methods: In this study, the sampling gases exited from cement plant stack were carried out using Testo XL350 and particulates measurement done by Westech device. SCREEN3 software model was used to evaluate air quality and dispersion NO_X, SO₂ and PM. Data interred into the model includin emission rate, physical factor related with stack, height, length and width building, mixing height, meteorological stability and wind speed. This model incorporates sources related factors, meteorological factors and emission rates to estimate pollutant concentration from continuous sources. The class stability and wind speed were at a  hight of 10 meter.

Results: The results showed that the maximum concentration predicted NO_X, SO₂ and PM by SCREEN3 in neutral condition (D) and wind speed 6 m/s was at 1084 m away from stack with concentration of 265.48µg/m³, 168.39µg/m³ and, 56.56µg/m³ for NO_X, SO₂ and PM respectively. Also, at stability condition (F) with wind speed 4 m/s the maximum concentration predicted in 2647 m away of stack with amount of 195.71µg/m³, 308.54µg/m³ and 65.37µg/m³ respectively. 

Conclusion: In order to reach the clean air  standard, continuous monitoring and development methods are necessary for control gases and particulates exited from stack.