Application of ISC-AERMOD program for evaluation of air pollutants dispersion in Siriraj hospital

Abstract

The dispersion of air pollutants emitted from the boiler stack located at Siriraj Hospital was predicted by using ISC-AERMOD View program. In this research, the types of air pollutants including carbon monoxide (CO), nitrogen dioxide (NO2) and sulfur dioxide (SO2) were indicated because of their adverse effect on human health. The CO, NO2 and SO2 concentrations in the atmosphere and from the mobile sources surrounding Siriraj Hospital were determined and used as the background concentrations for evaluating the values of their maximum concentrations in order to compare to the ambient air quality standard in Thailand. The results showed that the maximum background concentrations of SO2 for 24 hr and yearly, CO for 1 hr and 8 hr, and NO2 for1 hr were 0.011 ppm, 0.011 ppm, 2.196 ppm, 2.134 ppm, and 0.015 ppm, respectively. The predicted results revealed that the dispersion of SO2 and NO2 was approximately 285 m from the boiler stack through the eastern part of the boiler while the CO dispersion was about 137 m from the boiler stack to the eastern part or the Chlermprakiet Building area. Also, the predicted maximum concentrations of SO2 for 24 hr and yearly, CO for 1 hr and 8 hr, and NO2 for1 hr were 0.010 ppm, 0.005 ppm, 0.0001 ppm, 0.00002 ppm, and 0.0097 ppm, respectively. Therefore, the maximum concentrations resulting from the background and predicted maximum concentrations for SO2 at 24 hr and yearly, for CO at 1 hr and 8 hr and for NO2 at 1 hr were 0.021 ppm, 0.016 ppm, 2.1962 ppm, 2.1345 ppm and 0.024 ppm, respectively. These concentrations were less than the concentrations in the ambient air quality standards. As a result, SO2, CO and NO2 emitted from the boiler stack at Siriraj Hospital might be slightly affected and less harmful to the hospital workers. However, to confirm the adverse effect on the hospital workers the risk assessment of air pollutants should be determined.