Road grade is an important variable that affects engine power demand and hence the fuel consumption and tailpipe emissions of vehicles. However, no prior works have evaluated the effects of road grade on tailpipe volatile organic compound (VOC) emissions of motorcycles. This study investigated the effects of road grade on real-world tailpipe emissions of carbon monoxide (CO), carbon dioxide (CO₂), total hydrocarbons (THC), nitric oxide (NO), and speciated VOCs for a Euro 5 motorcycle. Real-world emissions of CO, CO₂, THC, and NO were measured in real-time using a miniature portable emissions measurement system (mini-PEMS), while VOCs were measured in integrated exhaust samples collected during real-world driving. PEMS tests (n = 20) were conducted on urban (UR), suburban (SU), uphill (UH), and downhill (DH) routes. The road grade range encountered in this study was approximately −14 % to +14 %. The mean UH emission factors of CO, THC, and ΣVOC were 9890 ± 1619, 101.0 ± 6.7, and 18.81 ± 4.31 mg/km, respectively. Likewise, the DH emission factors were 202 ± 197 mg/km for CO, 10.3 ± 2.9 mg/km for THC, and 1.49 ± 0.68 mg/km for ΣVOC. The emission factors of all measured pollutants on the UH route were significantly higher than the DH and baseline (mean of UR and SU) emission factors. The results of the present study may help identify emission hotspots along the roads and formulate traffic air pollution control strategies.

道路坡度是影响发动机功率需求的重要变量，从而影响车辆的油耗和尾气排放。然而，之前没有研究评估道路等级对摩托车尾气挥发性有机化合物 (VOC) 排放的影响。本研究调查了道路等级对欧 5 摩托车实际尾气排放的一氧化碳 (CO)、二氧化碳 (CO ₂ )、总碳氢化合物 (THC)、一氧化氮 (NO) 和特定 VOC 的影响。CO、CO _{2 的}实际排放量、THC 和 NO 是使用微型便携式排放测量系统 (mini-PEMS) 实时测量的，而 VOC 是在真实驾驶过程中收集的综合排气样本中测量的。PEMS 测试 (n = 20) 在城市 (UR)、郊区 (SU)、上坡 (UH) 和下坡 (DH) 路线上进行。本研究中遇到的道路坡度范围约为 -14 % 至 +14 %。CO、THC和ΣVOC的平均UH排放因子分别为9890±1619、101.0±6.7和18.81±4.31mg/km。同样，CO 的 DH 排放因子为 202 ± 197 mg/km，THC 为 10.3 ± 2.9 mg/km，ΣVOC 为 1.49 ± 0.68 mg/km。UH 路线上所有实测污染物的排放因子均显着高于 DH 和基线（UR 和 SU 的平均值）排放因子。