Exposure Assessment on Volatile Organic Compounds (VOCs) for Tollway Station Workers via Direct and Indirect Approaches

Exposure Assessment on Volatile Organic Compounds (VOCs) for Tollway Station Workers via Direct and Indirect Approaches: Ching‐Chang L ee , et al. Department of Environmental and Occupational Health, Medical College, National Cheng Kung University —The present study was set out to assess the exposure levels of volatile organic compounds (VOCs) for tollway station workers via direct and indirect approaches. For direct approach, personal samplings were conducted on 25, 30 and 31 booth attendants of a tollway station during the dayshift (08:00 AM‐16:00 PM), nightshift (16:00 PM‐24:00 AM), and late‐nightshift (24:00 AM‐08:00 AM), respectively. For each collected sample, five target VOCs including benzene, toluene, xylene, ethylbenzene and methyl tertiary‐butyl ether (MTBE) were analyzed. Results show that at least four of the exposure profiles of the five target VOCs for the booth attendants on any given workshift were log‐normally distributed. The above results suggest that the booth attendants on any given workshift can be regarded as a similar exposure group (SEG). The exposure levels for both the dayshift and the nightshift booth attendants were quite similar, but were significantly higher than those for the late‐ nightshift booth attendants. A similar tend was found in the vehicle flow rates. The above results indicate that the difference in VOC exposure levels for the booth attendants on the three workshifts could be due to the intrinsic difference in the vehicle flow rates. After conducting linear regression analyses, we found that the vehicle flowrates were able to explain the variation in VOC exposure levels up to 40%‐52%. It is concluded that the vehicle flow rates can be used as an indirect indicator for predicting the booth attendants’ VOC exposure levels.