Short-term variation in occupational exposure to air contaminants.

Many industrial workers are exposed to air contaminants. A significant proportion of this exposure is found to occur as short peaks, a fact that has received limited attention in the literature. The present study focuses on short-term variation in air contaminant exposure measured at the level of seconds, linking exposure peaks to typical work situations in selected Swedish industries. The video exposure monitoring method was used to characterize this variation. Ten different videos were analyzed, from recordings varying in length between 15 and 34 minutes. Cumulative exposure for sampling intervals ranked from high to low, relative to the total exposure was calculated as a function of time. Measures of exposure variation included geometric standard deviation and maximum exposure divided by arithmetic mean. The results show that the characteristics of the variation differ between industrial situations. Samples from the stone, wood, and pharmaceutical industries generated the highest variation, implying that exposure peaks of short duration explain a large proportion of the total exposure. It can be concluded that video monitoring of exposure, combined with calculation of exposure variation as percentage of time accounting for given percentages of exposure, can help to reduce exposure to air contaminants in industrial situations by introducing more targeted control measures.