Abstract

The highway toll booth workers receiving the fee are likely to be exposed to the diesel exhaust gas. So, we assessed the exposure levels of the black carbon (BC) and the elemental carbon (EC).

The 10 highway offices were evaluated in September 2015 and 1 ∼ 4 booths at each office was selected. The BC was checked 3 to 5 times at each point with real time portable Aethalometer (Microaeth AE51). The EC was collected in Quarts filters for 7 hours and analysed with OCEC analyzer(Model 5, Sunset Lab. Inc.) by NIOSH NMAM 5040.

The mean levels of BC were 2.1∼10.1 μg/m³ in the booths. The mean levels of EC were 1.8∼7.2 μg/m³ and 2.5∼10.0 μg/m³ in the booths and outside of the booths, respectively. The EC levels of outside of the booth were higher than the levels of in the booth. The levels of EC were 0.3∼1.5 μg/m³ in the office room. All the measurement results were lower than 20 μg/m³ that was suggested by ACGIH in the past but now it was withdrawn. The in/out ratio of EC was 0.67∼1.09, and the relationship between inside and outside EC concentration was very high (R2 = 0.855) Between the concentration of the BC and the EC showed a high correlation (R2 = 0.756). Interest about the diesel emissions is increasing, but there is no reliable exposure limits. A lot of research about the evaluation methods and health effects for the hazards of diesel emissions are needed.