CHARACTERIZATION OF REAL-WORLD VEHICLE EMISSION FACTORS IN A ROAD TUNNEL

摘要

Real-world vehicle emission factors are determined from on-road measurements carried out in Yangkou tunnel of Qingdao city. Concentrations of paniculate matter and gaseous-species (CO and CO_2) are monitored continuously from May 26 to September 23, 2011. Then the fuel-based emission factors of pollutants inside the tunnel are calculated based on the fuel carbon balance method. It is calculated that the average emission factors of particle number and mass are (1.068±0.695)×10~(15)particle kg~(-1) and (213.6+155.2) mg kg~(-1) respectively. As for gaseous pollutants, CO and CO_2 average emission factors are (80.727+70.133) g kg~(-1) and (4.077±0.923)×10~3 g kg"1 respectively. To overall reflect the emission variation of mixed vehicles, the emission profiles of each measured pollutants are illustrated. Moreover, the calculated emission factors in this study are compared with the previous published results. The possible reasons bringing about the estimation deviation are pointed out and one of the discrepancies can attribute to the uncertainties of on-road traffic information of the investigated vehicles. Thus, a series of effect parameters on emission factors are analyzed using multivariate regression method, taking an example of particle number emission. It is found that traffic density shows a strong relationship with particle number emission. These results in this study offer basic understanding to investigate the traffic emissions of Qingdao city.