製紙工場周辺の臭気に関する調査研究(3) : 大気拡散式による環境濃度の計算

Abstract

With two of the data presented in the preceding report, we calculated the ground-level odorant concentrations by employing a diffusion formula; the one (dated July 16,1985) relates to site D and the other (January 22,1986) to site A, the atmospheric stabilities judged being class A～;B or B in the Pasquill-Gifford system for site D and class C～D or D for site A. The odorants measured were hydrogen sulfide, methyl mercaptane, methyl sulfide and dimethyl disulfide; they were supposed to be discharged from five stacks of the mill. It has been found that the calculated concentration is distinctly different from the measured, the latter for site D being as large as 150 times or more the former and for site A, 4,000 times or more. To explain the discrepancy, we examined closely some draw-backs involved in the formula, and finally, we have come to the conclusion that odor escaping from chipdigesting work-shops is the primary one and those from waste-water clarifiers and the like may join to it; the mixture thus produced will travel over the ground down-wind to form the ambient odor. Additional mention was made of the result of our calculation reckoning account of surface roughness of the study area.