本論文針對基隆港區兩艘同型4000匹馬力(hp)港勤拖船，從2013年8月份正式啟航後至2016年12月31日航行與作業期間，主機實際作業轉速與工況，區分成怠速(load 25%)、小俥(load 50%)、中俥(load 75%)及大俥(load 85%)四種作業工況模式，相對應實測主機空污排放氣體流速與四種排放濃度值分別為CO₂、NOₓ、CO及SO₂，四種作業工況模式的平均值排放量，與美國環保署(US EPA)港勤船活動強度推估公式計算及採用燃油消耗量計算方式比較之差異。由於利用主機實際作業區分四種作業工況模式，相對應排放的流速與濃度，比較符合拖船實際作業的排放情況，藉此修正兩艘拖船四種氣體實際的排放係數值。

In this study, we analyzed two 4000-hp harbor tugboats in the Port of Keelung, Taiwan, from their formal commissioning in August 2013 till December 31, 2016. We classified the operating modes of the main engine (M/E) into loads of 25%, 50%, 75%, and 85% to test CO₂, NOₓ, CO, and SO₂ concentrations relative to the gas emission rates of the M/E. We calculated the average emissions from the tugboats under the four operating loads using the harbor vessel activity intensity evaluation formula and the fuel consumption formula proposed by the US EPA and compared the results. The emission rate and concentration measured under the four operating loads better reflect the real-time operating conditions of the tugboats. The proposed method can be used to revise the emission factors of the two tugboats under different loads.