本研究針對高速公路隧道(T1、T2)大氣與其周界大氣進行採樣分析，T1隧道Inlet及Outlet測得之PM2.5濃度分別為21.9±6.93 μg/m3及46.1±11.7 μg/m3，而T1周界大氣採樣點測得之PM2.5濃度為12.5±6.20 μg/m3。T2隧道Inlet及Outlet測得之PM2.5濃度分別為36.5±6.05 μg/m3及151±39.1 μg/m3，而T2周界大氣採樣點測得之PM2.5濃度為14.1±4.31 μg/m3。兩周界大氣測站之PM2.5濃度亦明顯低於隧道大氣濃度，可見車輛排氣對大氣PM2.5濃度貢獻顯著。利用隧道大氣採樣結果計算T1與T2隧道PM2.5之車輛行駛里程數排放係數(EFVKT)分別為10.9±1.06、7.93±1.29 mg-PM2.5/km-vehicle。而T1隧道計算之氣相PAHs之平均EFs為385±92.8 μg/km vehicle，遠高於固相PAHs (22.1±5.61 μg/km vehicle)。T2隧道計算之固相PAHs平均EFs為1.44±1.09 μg/km vehicle，而氣相PAHs平均EFs為6.29±2.47 μg/km vehicle，亦高於固相PAHs。本研究亦針對汽、柴油車於惰轉及高速運轉(70 km/hr)之車輛排氣進行採樣分析，汽油車PM2.5濃度於惰轉及高速運轉分別為0.2 mg/m3及0.4 mg/m3，柴油車之PM2.5濃度於惰轉及高速運轉分別為3.5 mg/m3及4.7 mg/m3，而惰轉之柴油車固相PAHs平均濃度(∑27PAHs：467 ng/m3)明顯高於汽油車(∑27PAHs：1.68 ng/m3)，高速運轉(70 km/hr)期間柴油車固相PAHs平均濃度(∑27PAHs：82.3 ng/m3)亦明顯高於汽油車(∑27PAHs：9.72 ng/m3)。因國內道路之車種分佈以汽油車占較高比率，而汽油車之固相PAHs物種分布以PA、Pyr、Flu及FL為主，故與兩隧道之固相PAHs物種分布一致。雖然固相PAHs以上述四物種為主，但未來國內若要規範PAHs勢必不能忽略毒性當量係數較高之物種(BcFE之TEF值為20)。;This study aims to sample and analyze the PM2.5 and PAHs concentrations of the highway tunnels (T1, T2). The PM2.5 concentrations measured at the T1 tunnel inlet and outlet were 21.9±6.93 μg/m3 and 46.1±11.7 μg/m3, respectively. The ambient PM2.5 concentration measured at the T1 was 12.5±6.20 μg/m3. The PM2.5 concentrations measured at the T2 tunnel inlet and outlet were 36.5±6.05 μg/m3 and 151.0±39.1 μg/m3, respectively. The ambient PM2.5 concentration measured at the T2 was 14.1±4.31 μg/m3. The results indicate that the vehicle exhaust contributes significantly to the atmospheric PM2.5 concentration. The vehicle kilometers traveled-based emission factors (EFVKT) of T1 and T2 tunnels calculated with the tunnel sampling results are 10.9±1.06 and 7.93±1.29 mg-PM2.5/km-vehicle, respectively. The sampling results of the particle-phase and gas-phase PAHs concentration are substituted into the emission factor formula to obtain the EFVKT. The average EFs of the gas-phase PAHs calculated for the T1 tunnel is 385±92.8 μg/km vehicle, which is much higher than the particle-phase PAHs (22.1±5.61 μg/km-vehicle). The average EFs of particle-phase PAHs calculated for the T2 tunnel is 1.44±1.09 μg/km-vehicle, while the average EFs of gas-phase PAHs is 6.29±2.47 μg/km-vehicle. This study also aims to sample and analyze the PM2.5 and PAHs concentrations of vehicle exhaust in idle and high-speed operation (70 km/hr) for gasoline and diesel vehicles. The PM2.5 concentrations of the gasoline vehicle at idle and high speed were 0.2 mg/m3 and 0.4 mg/m3, respectively. The PM2.5 concentrations of diesel vehicle at idle and high speed were 3.5 mg/m3 and 4.7 mg/m3, respectively. The concentration of particle-phase PAHs in diesel vehicles during idle (∑27PAHs：467 ng/m3) is significantly higher than that of gasoline vehicles (∑27PAHs：1.68 ng/m3). The concentration of particle-phase PAHs in diesel vehicles during high-speed operation (70 km/hr) (∑27PAHs：82.3 ng/m3) is also significantly higher than that of gasoline vehicles (∑27PAHs：9.72 ng/m3). Because of the higher proportion of gasoline vehicles in Taiwan, the PAHs species distribution of gasoline vehicles is mainly PA, Pyr, Flu and FL, which is consistent with the particle phase PAHs species distribution of the two tunnels. Although the particle-phase PAHs are mainly composed of the above four species, in the future, if the PAHs are to be regulated in Taiwan, the species with high toxicity equivalent coefficients must not be ignored.
