자동차 배출가스 중 BTEX의 비율과 C₂-benzenes의 상관성 연구

A Study on the BTEX Ratio and Correlation of C₂-benzenes in Vehicle Exhaust

Abstract

Benzene, toluene, ethylbenzene and xylene (BTEX) were well known as ozone precursors from photochemical reactions and contribute to the formation of photochemical smog which pose health hazards. Also, some of these compounds directly affect the human health due to their toxicity such as benzene. In this study, BTEX ratios and correlation of $C_2$-benzenes (xylenes, ethylbenzene) in vehicle exhaust from recreational vehicle (RV) and multi-purpose vehicle (MPV) were characterized using a chassis dynamometer. VOCs were collected by tedlar bag and a GC/MS system was used for their quantification. Among all of the BTEX, toluene has the highest concentration(more than 30% in composition of BTEX). The average ratio of toluene to benzene emissions (T/B ratio=2.2) was found in vehicle exhaust. The average m,p-xylene/ethylbenzene and m,p-xylene/o-xylene ratios were 1.0 and 3.0 respectively. As a result, it showed a good correlation between the $C_2$-benzenes ($R^2=0.98{\sim}0.99$). In the future, it can be used as a marker for effect evaluation to atmospheric environment by vehicle exhaust.

Fig. 1 The driving patterns on NIER modes

Fig. 2 Schematic diagram on vehicle emission test process

Fig. 3 Comparison of the BTEX distribution at different sources

Fig. 4 Correlation between m,p-xylene and o-xylene

Fig. 5 Correlation between m,p-xylene and ethylbenzene

Table 1 Specifications of the tested vehicles

Table 2 Specifications of driving mode

Table 3 Analysis conditions of TD and GC/MS

Table 4 Emission of the BTEX

Table 5 Correlations between BTEX compounds