Open coal storage piling is considered as pollution concerned activity because when the air is dry and windy, the coal dust can disperse and cover large area causing air pollution. Knowing in advance the concentration and area affected by the coal dust emitted from a coal storage pile is important. It is, therefore, the purpose of this study to estimate the emission rate of coal dust from an open coal storage pile, and to simulate its dispersed concentration in the environment. The emission rate of 2.26539×10-4 g/m2/s from an open coal storage pile was calculated from 16 coal samples. The simulated results by using the AERMOD model show that coal dust concentrations dispersing from a 120×60×10 m3 open coal storage pile are below the allowable concentration standard given by the Pollution Control Department of Thailand. The largest and smallest areas affected by the coal dust are in winter (2.124 km2 ) and rainy season (0.116 km2 ) respectively, but the winter and rainy season concentrations are 67 to 132 µg/m3 and 133 to 98 µg/m3 respectively. Dust protection measures should be applied to coal storage piles especially in winter.
