UH-1H直升機引擎多環芳香烴化合物排放特徵之研究

Emissions of Polycyclic Aromatic Hydrocarbons (PAHs) from UH-1H Aircraft Turboshaft Engine2

本研究探討UH-1H直升機引擎尾氣之多環芳香烴化合物（polycyclic aromatic hydrocarbons, PAHs）排放特徵與排放係數。在五種測試模式下利用煙道等速採樣方法收集PAHs，結果顯示航空器引擎各測試模式之總PAHs（Total-PAHs）濃度高低依序分別為：GI（Ground Idle）（1653 μg/m3）＞ IGV（Inlet GuideVane）（840 μg/m3）＞TO（Take Off）（720 μg/m3）＞BBC（Beed Band Check）（594 μg/m3）＞FI（FlightIdle）（410 μg/m3）。五種測試模式平均Total-PAHs排放濃度為843 μg/m3，平均Total-BaPeq排放濃度為3.94 μg/m3。Total-PAHs 主要以低分子量為主要組成，約佔97.5%。各測試模式Total-PAHs 排放係數（EFTotal-PAHs）依序分別為：GI（676 mg/L fuel）＞IGV（232 mg/L fuel）＞BBC（210 mg/L fuel）＞TO（186 mg/L fuel）＞FI（151 mg/L fuel），平均EFTotal-PAHs為291 mg/L fuel，該值高於四行程機車使用95無鉛汽油45.6 倍，92 無鉛汽油107 倍、高級汽油76.6 倍及重型柴油引擎7.86 倍。平均Total-BaPeq 排放係數（EFTotal-BaPeq）為1.44 mg/L fuel。若計算機場起降循環（Landing and Takeoff, LTO）之排放係數，平均EFTotal-PAHs 為21.8 g/LTO；平均EFTotal-BaPeq 為42.5 mg/LTO，該排放係數遠高於歐盟規範值1.24mg/LTO。由以上結果得知直升機引擎相較於陸地上移動性污染源有較高的PAHs排放濃度與排放係數，對於航空器測試勞工或機場地勤人員可能有較高的潛在危害，且對大氣環境之貢獻量應不容忽視。

The objectives of this study were set out to assess the characteristic and emission factor of polycyclic aromatic hydrocarbons (PAHs) from aircraft of UH-1H helicopter (turboshaft engine) emission. We collected flue PAHs with isokinetic sampling during the 5 modes of GI (Ground Idle), FI (Fly Idle), BBC (Beed Band Check), IGV (Inlet Guide Vane), and TO (Take Off), respectively. The PAHs levels showed in sequence were GI (1653 μg/m3) ＞IGV (840 μg/m3)＞TO (720 μg/m3) ＞BBC (594 μg/m3)＞FI (410 μg/m3 ) in 5 modes. The mean concentrations of total PAHs and total BaPeq were 843 and 3.94 μg/m3, respectively. The major composition of total PAHs was LMW (low molecular weight) about 97.5%. The emission factor of total PAHs (EFTotal-PAHs) showed in sequence was GI (676 mg/L fuel) ＞IGV (232 mg/L fuel) ＞BBC (210 mg/L fuel) ＞TO (186 mg/L fuel) ＞FI (151 mg/L fuel) and its mean EFTotal- PAHs was 291 mg/L fuel. This level was 45.6, 107, 76.6 and 7.86 times higher than 95-lead-free gasoline, 92-lead-free gasoline and premium leaded gasoline from the 4-stroke engine, and diesel from the heavy-duty diesel engine, respectively. The estimation of mean emission factor of total BaPeq (EFTotal-BaPeq) was 1.44 mg/L fuel in 5 modes. We also estimated emission factor of landing and takeoff (LTO) cycle. The emission factor of total PAHs and mean BaP were 21.8 g/LTO and 42.5 mg/LTO from this aircraft in LTO cycle. This level of BaP emission factor was higher than regulation of European Communities level (1.24 mg/LTO). As the results there were higher emission concentration and emission factor from this aircraft engine than on-road motive emission source such as motor vehicle engine.