Size-selective sampling of oil mist in air and subjective symptoms among machine workers

Oil mists at an automobile factory were measured size-selectively. Furthermore, subjective symptoms were surveyed through the distribution of a questionnaire. The measured levels of respirable-size, 2-10 micrometer oil mists at 3 selected workshops ranged 0.04-0.09 mg/m3 for the lower exposed group (17 men), 0.10-0.18 mg/m3 for the higher exposed group (16 men) to water-insoluble oil, and 0.08-0.29 mg/m3 for the higher exposed group (19 men) to water-soluble oil. The higher the level of exposure to respirable-size particulates, the more workers complained of dissatisfaction with air quality. As to the subjective symptoms, the "yes" rate for "irritated nose" and "sneezing" showed significant differences among the unexposed, lower exposed, and higher exposed groups. Workers using water-soluble oil complained of "uncomfortable smell" more than those who used water-insoluble oil. The results of this study suggested that it is necessary to measure the levels of oil mists size-selectively.