oil refinery no relation air pollution
Cause
All clinical cases of Yokkaichi asthma began after the establishment of the oil refinery and petroleum chemical plants in 1959.Complaints from citizens of offensive odors spurred investigation. Initially, the suspected sources of the odors included SO2, hydrogen sulfide (H2S), methylmercaptan, aldehydes, and other substances found to be leaking from the factories. However, sulfur dioxide emitted from the combustion of high sulfur content oil has typically been attributed as the cause of the disease since the beginning.
Despite common belief that SO2 was the main source of the asthma, by investigating sulfur dioxide and sulfur trioxide levels in Yokkaichi and analyzing compound toxicity levels, a study conducted in 1984 from Yokohama National University concluded that respiratory diseases were not a result of sulfur dioxide, but rather due to a titanium oxide manufacturing plant venting concentrated sulfuric acid mists downwind onto populated urban areas. The high concentration of Yokkaichi asthma patients in Isozu Village can be farther accounted for under this conclusion, as the source of sulfur trioxide emissions is 2 kilometers south of the most affected population. A 2001 study by several researchers in the Environmental Management journal confirmed by analyzing the effects of SO2 and SO3 on humans that SO3 was likely the real cause of the asthma. They farther propose that one of the reasons flue-gas desulfurization implementation did not lead to the disappearance of all cases was due to differences in SO2 and SO3 cleanup.
no relation