Tsai Perng-Jy, Shih Tung-Sheng, Chen Hsiao-Lung, Lee Wen-Jhy, Lai Ching-Huang, Liou Saou-Hsing
Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan R.O.C.
Environ Sci Technol. 2002 Nov 15;36(22):4748-53. doi: 10.1021/es020721t.
The present study was set out to assess the contents of polycyclic aromatic hydrocarbons (PAHs) in three types of tollbooths at a highway toll station via direct and indirect approaches. Direct sampling results show that no significant difference could be found in the PAH homologue distributions for samples collected from the car lane/ticket-payment and car lane/cash-payment tollbooths, but both were significantly different from that for the bus/ truck lane tollbooth. The above results could be due to the former two types of tollbooths that were designed for the same type of traffic (i.e., cars and vans), but the latter was designed for a different type of traffic (i.e., buses and trucks). For any given type of tollbooth, the total-PAH content (C(Total-PAHs)) found during the day shift (= 9,370-15,500 ng/m3) were not significantly different from that found during the night shift (= 9,550-14,900 ng/m3), but both were significantly higher than that found during the late-night shift (= 5,560-11,100 ng/m3). During any given work shift we found C(Total-PAH5) for the three types of tollbooths as the following: bus/truck lane (= 11,100-15,500 ng/m3) > car lane/ticket-payment (= 7,260-13,500 ng/m3) > car lane/ cash-payment (= 5,560-9,550 ng/m3). After conducting multivariate regression analyses, we found that none of the three environmental factors (i.e., wind speed,temperature, and relative humidity), except for the vehicle flow rate (Q(Vehicle)) had a significant effect on C(Total-PAHs) for any given type of tollbooth. Considering directly measuring PAH contents was labor-consuming and costly, and the above results suggest the possibility of using Q(Vehicle) to predict C(Total-PAHs) for any given type of tollbooth. After conducting simple linear regression analyses, we found that (1) all resultant regression coefficients were found with positive values indicating that an increase in the Q(Vehicle) would lead to an increase in the C(Total-PHHs). (2) from the magnitude of the resultant regression coefficients indicating that an increase in C(Total-PAHs) caused by per unit Q(Vehicle) for the three types of tollbooths were the following: bus/truck lane > car lane/cash-payment > car lane/ticket-payment, and (3) the resultant R2 values fell to the 0.54-0.75 range indicating that the variations in C(Total-PAHs) could be explained well by Q(Vehicle) for the three types of tollbooths. It is concluded that measuring Q(Vehicle) can be regarded as an effective indirect method for estimating PAH contents in various types of tollbooths.
本研究旨在通过直接和间接方法评估某高速公路收费站三种类型收费亭中多环芳烃（PAHs）的含量。直接采样结果表明，从汽车车道/缴费窗口和汽车车道/现金缴费窗口采集的样本中PAH同系物分布无显著差异，但这两者与公交/卡车车道收费亭的样本均有显著差异。上述结果可能是因为前两种类型的收费亭是为同一类交通方式（即汽车和厢式货车）设计的，而后者是为不同类型的交通方式（即公交车和卡车）设计的。对于任何给定类型的收费亭，白班期间测得的总PAH含量（C（总PAHs））（=9370 - 15500纳克/立方米）与夜班期间测得的（=9550 - 14900纳克/立方米）无显著差异，但两者均显著高于深夜班期间测得的（=5560 - 11100纳克/立方米）。在任何给定的工作班次中，我们发现三种类型收费亭的C（总PAH5）如下：公交/卡车车道（=11100 - 15500纳克/立方米）>汽车车道/缴费窗口（=7260 - 13500纳克/立方米）>汽车车道/现金缴费窗口（=5560 - 9550纳克/立方米）。进行多元回归分析后，我们发现，对于任何给定类型的收费亭，除车流量（Q（车辆））外，三种环境因素（即风速、温度和相对湿度）对C（总PAHs）均无显著影响。考虑到直接测量PAH含量既费力又昂贵，且上述结果表明利用Q（车辆）预测任何给定类型收费亭的C（总PAHs）具有可能性。进行简单线性回归分析后，我们发现：（1）所有所得回归系数均为正值，表明Q（车辆）增加会导致C（总PAHHs）增加。（2）从所得回归系数的大小来看，三种类型收费亭每单位Q（车辆）导致的C（总PAHs）增加情况如下：公交/卡车车道>汽车车道/现金缴费窗口>汽车车道/缴费窗口，（3）所得R2值在0.54 - 0.75范围内，表明三种类型收费亭的C（总PAHs）变化可以由Q（车辆）很好地解释。得出结论，测量Q（车辆）可被视为估算各类收费亭中PAH含量的一种有效间接方法。
