Abstract In recent years, with the rapid growth of traffic flow in highway tunnels, the in-tunnel environmental pollution problem has aroused widespread concern in China. Previous studies mainly focused on the emission factors in tunnels dominated by passenger cars (PCs) and light commercial vehicles (LCVs). However, this study concentrated on the characteristics of traffic flow dominated by heavy-goods vehicles (HGVs), environmental monitoring and assessment in highway tunnels in mountainous areas. To explore the emission characteristics of vehicle pollutants in highway tunnels in such regions, a field measurement was conducted in Qinling No. 3 Tunnel in China, focusing on the traffic volume, air velocity, and pollutant concentration. Measurement results show that the average daily traffic volume in Qinling No. 3 Tunnel is 22,218 pcu/d, with the HGVs comprising more than 65%. The average air velocity in case tunnel reaches 5.09 m/s. The average concentrations of NH3, SO2, CO, and NOx in the tunnel are 4.54 ppm, 0.06 ppm, 6.22 ppm, and 4.39 ppm, respectively. The single vehicle emission rates of measured pollutants are calculated based on collected data, among which, the emission factor of NOx is the largest (average: 9.37 g/(km·veh)), while that of SO2 is the lowest (0.09 g/(km·veh)). The results show that the dilution of NO2 in the tunnel should be considered in the ventilation design of highway tunnels.

中文翻译：

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山区以重型货车为主的公路隧道污染物浓度测量及排放因子分析

摘要 近年来，随着公路隧道车流量的快速增长，隧道内环境污染问题在我国引起了广泛关注。以往的研究主要集中在以乘用车（PC）和轻型商用车（LCV）为主的隧道中的排放因子。然而，本研究集中在以重型货车（HGV）为主的交通流特征、山区公路隧道的环境监测和评估。为探索该地区公路隧道车辆污染物排放特征，在秦岭三号隧道进行了现场测量，重点测量了车流量、风速和污染物浓度。测量结果表明，秦岭三号隧道日均交通量为22218 pcu/d，重型货车占 65% 以上。案例隧道内的平均风速达到5.09 m/s。隧道中NH3、SO2、CO和NOx的平均浓度分别为4.54 ppm、0.06 ppm、6.22 ppm和4.39 ppm。根据收集到的数据计算实测污染物的单车排放率，其中NOx的排放因子最大（平均：9.37 g/(km·veh)），SO2的排放因子最低（0.09 g/ (km·veh))。结果表明，公路隧道的通风设计应考虑对隧道内NO2的稀释。实测污染物的单车排放率是根据收集到的数据计算得出，其中NOx排放因子最大（平均9.37 g/(km·veh)），SO2排放因子最低（0.09 g/ (km·veh))。结果表明，公路隧道的通风设计应考虑对隧道内NO2的稀释。根据收集到的数据计算实测污染物的单车排放率，其中NOx的排放因子最大（平均：9.37 g/(km·veh)），SO2的排放因子最低（0.09 g/ (km·veh))。结果表明，公路隧道的通风设计应考虑对隧道内NO2的稀释。