Modelling Emission Factors of Road Traffic From a Tunnel Study

Abstract

SUMMARYRoad emissions are one of the most important sources of primary air pollutants in the industrialized world. Here we describe the emission factors of road trac derived from measurements in the Gubrist tunnel (near ZuÈ rich, Switzerland). The measurements performed from 20 to 26 September 1993, included a large variety of compounds and detailed trac information. Multiple regression models have been used to calculate the emission factors of NO x , CO, total hydrocarbon (t-HC) and 26 individual hydrocarbons. Three types of vehicle classi®cations (light duty and heavy duty vehicles, gasoline and diesel powered vehicles and a re®ned version of the latter classi®cation) and two approaches for modelling the in¯uence of average vehicle speed (approximately 80 to 100 km/h) lead to ®ve dierent statistical models. A further model was developed for the description of the dependence of the relative composition of organic exhaust gases on average vehicle speed. This dependence was found to be weak but statistically signi®cant for several compounds. This paper describes why and how re®nements of simpler models were developed. If calculated emission factors are to be compared with results of other studies, several models may be needed.

Emissions of the Refrigerants HFC-134a, HCFC-22, and CFC-12 from Road Traffic: Results from a Tunnel Study (Gubrist Tunnel, Switzerland)

“…For benzene and toluene, the emissions of heavy duty vehicles are significantly lower than for the passenger cars. This finding corresponds to study of Staehelin et al (9) performed in the same tunnel in 1993, who related the effect to the difference that passenger cars are mainly powered by gasoline engines, while the heavy duty vehicles are powered by diesel engines. The emission factors for benzene and toluene derived from the Gubrist study in 1993 are given in Table 2 for comparison.…”

“…The Environmental Agency of Zürich (AWEL) and the regional air quality association Ostluft perform every other year a measurement campaign in the Gubrist tunnel to detect the development of the emission factors of the major car exhaust gases. In 1993, additionally intensive studies of organic exhaust gases and aerosols were performed at this site ( − ).…”

Chemical composition of ambient particulate matter and redox activity

“…This may due to the type of vehicles and gas and particle distribution of PAHs. Staehelin et al observed a significant correlation between heavy PAHs and light-duty vehicles and tricyclic PAHs and heavy-duty vehicles and naphthalene (Staehelin et al 1998). Five percent of diesel tracks may be the major source of lighter PAHs, whereas light-duty gasoline vehicle may be the dominant sources of higher molecular weight PAHs such as benzo[a]pyrene and dibenzo[a,h]anthracene (Miguel et al 1998).…”

Real-world vehicle emissions and VOCs profile in the Taipei tunnel located at Taiwan Taipei area

“…The important findings from the results of Van Nuys Tunnel study (Ingalls, 1989) revealed that motor vehicle emissions of CO and NMHC were about a factor 2 higher than the predictions by EMFAC7C. Similar road tunnel studies conducted in different places can be found in the articles, such as Gubrist Tunnel experiment of Switzerland (Staehelin et al, 1995(Staehelin et al, , 1997(Staehelin et al, , 1998John et al, 1999), Fort McHenry Tunnel experiment of Baltimore Harbor, Maryland (Pierson et al, 1996) and Tuscarora Mountain Tunnel of Pennsylvania (Sagebiel et al, 1996). All these kinds of activities contribute significantly to the improvement of the development of traffic emission models.…”