RESUMO
To investigate the an air pollution by particulate matter and its dispersion, a cement plant producing portland cement 600,000ton/year and its vicinity were surveyed from October, 1980 to April, 1983. The survey was mainly focused on main stack emission rate of the cement plant and particle size distribution in the dust, dustfall and total suspended particulate concentration in the area by month and distance from the stack. The results of the study were as follows; 1. The main stack emission rate was surveyed before and after the spray tower was additionally installed to the original E.P. and bag filter. Before the spray tower installed, the main stack emission rate was higher(0.64g/Nm3) than the emission standard of Korean Environmental Preservation Law's(0.5g/Nm3, amended to 0.4g/Nm3 on April 1983), but after the spray tower was installed, its main stack emission rate was markedly decreased to the standard (0.43g/Nm3). 2. 2~3 micrometer of the particle size was the largest portion(20.8%) of the dust particulate from the main stack and 50% of the frequency distribution was 1.5 micrometer of the size. Most particle size was below 10 micrometer. 3. The spray tower reduced the dustfall to 37.81~9.76ton/km2/month while dustfall appeared at 45.29-15.45ton/km2/month, in the vicinity of plant before spray tower installed. 4. Mean concentrations of total suspended particulate for 24 hours of the various stations were determined in 20.6-200.0 microgram/m3, 3 stations of them were higher than the value of Harry and William's arithmetic average standard 130 microgram/m3. 5. Linear regression between dustfall[X] and total suspended particulate[X] concentration was an equation, Y=4.024X+11.479.[r=0.91]. 6. During the whole seasons in the opposite area 100m apart from the emission source the prevailing wind direction was with estimated more than 30ton/km2/month, and the concentration of total suspended particulate for 24 hours averaging time was more than 140 microgram/m3 in the same area and direction. 7. Assuming the wind direction were constant through the day dustfalls for a day were estimated at 13.40ton/km2/day, 10.79ton/km2/day and 4.55ton/km2/day at various distances of 100m, 500m and 1,500m from the emission source respectively. 8. In the simutalion of dustfall and suspended dust by area, Gaussian dispersion model modified by size distribution of particulate matter was not applicated since the emission of dust were from multi sources other them stack. From the above results, it could be applied that the dispersion of dust from the cement plant is estimated and regulated for the purpose of environmental protection.