本研究以裝設柴油碳微粒過濾器（Diesel Particulate Filter， DPF）之柴油車為研究對象，蒐集國內粒狀污染物數目（Particle Number， PN）檢測資料，共納入6，352輛柴油車，分析不同排放期別、空氣污染防制設備組合及車輛特性對PN濃度之影響，並探討PN檢測應用於柴油車排放管理及DPF功能狀態評估之可行性。 研究結果顯示我國四期、五期及六期柴油車之PN濃度具有明顯差異，其中PN濃度中位數分別為3.08 × 10⁶、5.22 × 10⁵及1.40 × 10⁴ #/cm³，高排放比率則分別為70.42%、23.24%及3.65%。不同空氣污染防制設備組合之PN濃度、高排放車輛比率及低於檢出下限（Below Detection Limit， BDL）比率皆呈現顯著差異，其中配置DPF、選擇性觸媒還原系統（Selective Catalytic Reduction， SCR）及廢氣再循環系統（Exhaust Gas Recirculation， EGR）之車輛整體PN濃度及高排放比率均較低，顯示不同空氣污染防制設備組合具有不同之PN排放特性。進一步依排放期別比較後，各設備組合間之差異明顯縮小，顯示整體設備組合分析所呈現之PN排放差異可能部分受到各組排放期別組成差異影響，且不同排放期別車輛之PN排放特性仍呈現明顯差異。 所有受測車輛均已配置DPF，惟仍有19.88%車輛之PN濃度達1 × 10⁶ #/cm³以上；六期車輛雖多數PN濃度低於儀器檢出下限，亦有少數車輛超過高排放判定門檻。 本研究以1 × 10⁶ #/cm³作為高排放判定門檻，用以辨識PN濃度相對較高之車輛，並比較不同排放期別及車輛特性之高排放情形。研究結果亦顯示PN檢測可反映不同車輛之粒子排放特性，並可作為辨識異常高排放車輛及輔助評估DPF功能狀態之工具。整體而言，PN檢測除可作為柴油車排放管理工具外，亦可作為辨識異常高排放車輛及建立未來柴油車排放管理策略之重要參考。;This study investigated diesel vehicles equipped with diesel particulate filters (DPFs) using particle number (PN) measurement data collected in Taiwan. A total of 6，352 diesel vehicles were included to analyze the effects of different emission stages， combinations of air pollution control devices， and vehicle characteristics on PN concentrations， and to assess the feasibility of applying PN measurements to diesel vehicle emission management and the evaluation of DPF functional status. The results showed clear differences in PN concentrations among Taiwan Phase IV， Phase V， and Phase VI diesel vehicles. The median PN concentrations were 3.08 × 10⁶， 5.22 × 10⁵， and 1.40 × 10⁴ #/cm³， respectively， while the corresponding high-emission vehicle ratios were 70.42%， 23.24%， and 3.65%. Significant differences were also observed among different combinations of air pollution control devices in terms of PN concentrations， high-emission vehicle ratios， and below detection limit (BDL) ratios. Vehicles equipped with DPF， selective catalytic reduction (SCR)， and exhaust gas recirculation (EGR) systems exhibited lower overall PN concentrations and high-emission vehicle ratios， indicating that different combinations of air pollution control devices were associated with different PN emission characteristics. After further comparison by emission stage， the differences among device combinations were substantially reduced， suggesting that the differences observed in the overall analysis may have been partly influenced by differences in the emission-stage composition of each group， while PN emission characteristics remained clearly different among emission stages. Although all tested vehicles were equipped with DPFs， 19.88% of the vehicles had PN concentrations of 1 × 10⁶ #/cm³ or higher. Although most Phase VI vehicles had PN concentrations below the instrument detection limit， a small proportion still exceeded the high-emission threshold. In this study， 1 × 10⁶ #/cm³ was adopted as the high-emission threshold to identify vehicles with relatively high PN concentrations and to compare high-emission conditions among different emission stages and vehicle characteristics. The results also demonstrated that PN measurements can reflect differences in particle emission characteristics among vehicles and can serve as a tool for identifying abnormally high-emitting vehicles and assisting in the evaluation of DPF functional status. Overall， PN measurement can serve not only as a tool for diesel vehicle emission management but also as an important reference for identifying abnormally high-emitting vehicles and developing future diesel vehicle emission management strategies.
