基于隧道法的机动车对上海城市大气环境中氨的源排放贡献研究

Study on the Contribution of Vehicles to Ammonia Emission of Shanghai Atmospheric Environment Based on Tunnel Method

以上海交通最为繁忙的隧道之一的邯郸路隧道为研究对象,设计了隧道内(进口、中段、出口)机动车NH_3排放因子测定实验和隧道外(垂直于隧道口310 m范围内)机动车NH_3排放环境扩散梯度实验。隧道内实验结果表明,隧道出口的ρ(NH_3)分别是隧道进口和外围环境质量浓度的5倍和11倍,机动车NH_3排放因子(平均值±标准差)为(28±5)mg/km。据此估算,2014年上海机动车的NH_3排放总量约为1 300 t,占该市NH_3排放量的12%。梯度实验表明,邯郸路隧道出口处的机动车NH_3排放一旦扩散到大气中,其对环境的影响强度在短短数十米内迅速降低,超过150 m的范围后影响基本趋同。证实了在交通路网密集的城市,机动车是大气环境NH_3的重要来源,进而对城市颗粒物污染有潜在贡献。

One of the heavily trafficked urban tunnes （ Handan tunnel^） in Shanghai was taken as the object of this stiudy . Vehicularemission of ammonia has been determined in the tunnel （ the entrance, the middle sectsive gradients experiment on vehicular emission of ammonia from the outside of the tunnel （along a roperpendiculars to the tunnel） has been taken as well. Resuhs showed that NH3 concentrations （ meaover 5 and 11 times higher than those at the tunnel entrance and in the ambient air, respectively. Based on the based NH3 emission factor of （28 ±5 ） mgkm,thevvhicles in Shanghai produccd around 13 000 t NH3 in 2014, which accfor 12% of total NH3 emissions in the urban area. The gradient experiment showed that with the diffusion of ammonia at the exit of the tunnel, the impact of ammonia on the environment decreaseed quickly in tens of meters. This stiudy clearly shows that vehicle e-missions in urban areas with intensive traffic network are an important NH3 source and may have potential implications for particlespollution in the urban atmosphere.