Comparison of a road traffic emission model (HBEFA) with emissions derived from measurements in the Gubrist road tunnel, Switzerland

• Published in: Atmospheric environment (1994) Vol. 39; no. 26; pp. 4703 - 4714
• Main Authors: Colberg, Christina A., Tona, Bruno, Stahel, Werner A., Meier, Markus, Staehelin, Johannes
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2005; Elsevier Science
• Subjects: Applied sciences; Atmospheric pollution; Controlled converters; Emission factors; Emission models; Exact sciences and technology; Pollution; Pollution sources. Measurement results; Real-world emissions; Road traffic emissions; Transports; Validation of emission models; Switzerland; Europe; Switzerland, Bern; Austria, Niederoesterreich, Wien; Switzerland, Zuerich; Germany, Berlin; Emission factors; Validation of emission models; Emission models; Real-world emissions; Controlled converters; Road traffic emissions; Emission content; Motor vehicle; Pollutant emission; Validaticn of emission models; Road tunnel; Air pollution; Exhaust gas; Models; Road traffic; Emission measure; Measurement method; Comparative study
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2005.04.020

Road vehicle emissions contribute significantly to air pollution. These traffic emissions are characterized by emission factors (EFs), which describe the emitted mass of a compound per driven distance. Here, we present a comparison of EFs which were obtained with two different techniques: (i) Trace gas measurements in the Gubrist tunnel, Switzerland in fall 2002 (Colberg et al., 2005. Atmospheric Environment, in press) provided real-world EFs of entire vehicle fleets and, after statistical regression analysis, additionally the EFs of different vehicle classes. Furthermore, a 12 year time series of EFs of measurements in the Gubrist tunnel in Switzerland is being used (Steinemann und Zumsteg, 2003, Bericht US 89-16-11 für OSTLUFT durch Amt für Abfall, Wasser, Energie und Luft des Kantons Zürich (AWEL), Switzerland). (ii) Based on dynamometric test measurements and engine maps at different conditions, EFs of single vehicles are combined with a comprehensive road traffic emission model (HBEFA, 1999. Umweltbundesamt Berlin, Bundesamt für Umwelt, Wald und Landschaft Bern (published as software on CD-ROM), Infras AG, Bern; HBEFA, 2004. Umweltbundesamt Berlin, Umweltbundesamt Wien, Bundesamt für Umwelt, Wald und Landschaft Bern (published as software on CD-ROM), Infras AG, Bern). The results of both techniques are processed and if enough information on the vehicle fleet is available, a comparable standard is achieved, which allows the validation of the road traffic emission model. Since two HBEFA versions are being used the improvement of the model can be shown nicely. The results demonstrate good agreement for the trends of the time series measurements. However, a deviation for the absolute EFs of NO x is observed for light- and heavy-duty vehicles (LDV and HDV, respectively). The HBEFA, 2004 derived estimates are larger than 50% for LDV and 15% for HDV compared to the EF derived from the tunnel study. The deviation is even more prominent for the CO emissions (75% overestimation for LDV and 130% overestimation for HDV). The VOC emissions could only be compared for LDV. There the deviation is within the confidence interval of the measurements. The strengths and weaknesses of both techniques are revealed by this study.