ARTEMIS (2000-2003)

ARTEMIS = Assessment and Reliability of Transport Emission Models and Inventory Systems

ARTEMIS Table of Contents

Project Goal
Field Measurements
Results
Publications
Funding Agencies
Contacts
Links

• Assessment of traffic emission factors of various compounds. The contribution of PSI is the study of aerosol number size distributions.

In tunnel studies, measurements of various compounds are performed and statistically analysed concerning fleet composition air volume flux through tunnel, etc. in order to derive emission factors (often in gram/kilometre) of those compounds. The Paul Scherrer Institute does the SMPS measurements in order to derive information on the aerosol emissions in different size classes.

Field Measurements

Plabutsch Tunnel : November 2001

Results

QAQC aerosol activities

The SMPS systems used in the ARTEMIS project were inter-compared at several occasions and compared to instruments of other groups or instruments used in other projects :

• May 2001 : Heidelberg. Inter-comparison of SMPS-Systems within the framework of the BAB II (Bundesautobahn) project
• October 2001 : Inter-comparison of 3 SMPS-Systems at Paul Scherrer Institute
• November 2001 : Inter-comparison of SMPS-Systems in Graz

In all of these test campaigns, ammonium sulfate aerosols and ambient air were used for intercomparison. An example of an ammonium sulfate aerosol intercomparison within the October campaign is shown in Figure 1. The Systems with the data shown in yellow and red were used in Graz for the tunnel experiment. The blue colours indicate a third system, which is used by PSI in a different project. It turned out, that there was a leak in the inlet system of that third system, explaining the discrepancies seen in Figure 1.

Figure 1 : Intercomparison of 3 SMPS systems with ambient air aerosols.

First results from the Plabutsch tunnel experiment

The Paul Scherrer Institute did measurements in the Plabutsch-Tunnel in Austria. The goal of these measurements and of the other participants of the tunnel study is to assess emission factors of different vehicles (passenger cars, trucks) for various compounds. These emission factors will be used to validate theoretical calculation of emission factors (mostly derived from test bench studies). The Paul Scherrer Insitut focused on measurements of number size distributions of aerosols.

The measurements with a SMPS system were done both at the entrance and of the outlet of a ventilation channel allowing a determination of the addition of aerosols by the traffic emission in the tunnel. As the concentrations at the outlet are much higher than at the inlet (Figure 2 and 3), it will be possible to quantify the emissions due to the traffic emissions in the tunnel. The results show that aerosols with the highest emitted number concentrations have a diameter of around 100 nanometer (Figure 2) which is typical for soot aerosols.

Figure 2 : Aerosol number size distributions at the Plabutsch tunnel : Difference between exhaust and fresh air in the tunnel ventilation system.

Figure 3 : Aerosol number size distributions at the Plabutsch tunnel : Fresh air in the tunnel ventilation system.

Surprisingly, the emissions of ultrafine particles smaller than around 30 nanometers are lower than for the aerosols at 100 nanometers. In a former Swiss study, higher concentrations near the entrance of the Gubrist tunnel were found for the 30 nanometer particles than for the 100 nanometer particles (Weingartner et al., 1997). These ultrafine particles are believed to consist mainly of low volatile hydrocarbons with some sulphuric acid (Baltensperger et al., 2002). The reason for this discrepancy could be a different car and truck fleet. Other likely influences are the high aerosol surface concentrations in the Plabutsch Tunnel. At high concentrations, the low volatile hydrocarbon is more likely to condense on the existing particles than forming new ultrafine particles. Also temperature and humidity might influence the formation of the ultrafine particles. At higher temperature, the supersaturation of the condensable species is lower, which reduces the potential of homogeneous nucleation. Measurements outside of tunnels along highways show that in outdoor conditions the emissions of particles in the ultra-fine mode are much more dominant than in the tunnel study (Figure 4).

A first conclusion is that emission measurements of ultra-fine particles need to be interpreted carefully, especially when derived from tunnel measurements where high aerosol concentrations prevail. The soot mode at 100 nanometer is well interpretable. The concentrations in the tunnel are much higher during the day than during the night and the concentrations are also considerably lower at the weekend than during weekdays. The efforts in the inter-calibration have shown that thorough testing and comparison of the inlets and of the whole measurement systems are crucial in order to get quantitative results.

Figure 4 : Aerosol number size distributions measured next to the road at Birrfeld (Highway with 120 km/h speed limit)

Other activities with benefit for the Artemis Project

Outdoor near road measurements were performed at various locations. This will be important to put the measured tunnel data into perspective concerning differences of aerosol tunnel and aerosol outdoor measurements and into perspective concerning different driving conditions.

• 1.4.-31.5. 2001 Heidelberg : German Highway
• 21.6.-7.7. / 8.8.-21.8. 2001 : Birrfeld : Swiss Highway (speed limit : 120 km/h)
• 17.10.-29.10. 2001 : Humlikon : Swiss main road (speed limit : 100 km/h)
• December 2001 / January 2002 : Transalpine highways
• Various locations in and around Zurich Spring 2001-Spring 2002

Future activities

The SMPS data, especially the number concentrations around the soot mode can be used for the statistical evaluation of emission factors for the Plabutsch tunnel fleet and driving conditions. Beside the above described aerosol number distributions measured by a SMPS in the range of 15 to around 400 nanometer, we will analyze the data obtained by a OPC that measures particle number size distributions for larger particles. PSI took samples with a small deposit area impactor. These samples will be analysed for OC/EC by the group of Puxbaum in Vienna. Paul Scherrer Institute will participate in the next tunnel experiment (probably in England).

Publications

Baltensperger, U., N. Streit, E. Weingartner, S. Nyeki, A. S. H. Prévôt, R. van Dingenen, A. Virkkula, J.-P. Putaud, A. Even, H. ten Brink, A. Blatter, A. Neftel, and H. W. Gäggeler, 2002: Urban and rural aerosol characterization of summer smog events during the PIPAPO field campaign in Milan, Italy. J. Geophys. Res., 107, doi 10.1029/2001JD001292, 1-13.

Imhof, D., E. Weingartner, U. Baltensperger, U. Corsmeier, M. Kohler, F. Fiedler, U. Vogt, and G. Baumbach, 2002: Vertical distribution of particle sizes close to a motorway. 11th International Symposium, Transport and Air Pollution, Graz, Austria.

Imhof, D., E. Weingartner, U. Corsmeier, M. Kohler, F. Fiedler, U. Vogt, A. Dreiseidler, G. Baumbach, and U. Baltensperger, 2002: Particle size distributions near highly frequented roads , Zürich. 6th ETH-Conference on Nanoparticle-Measurement, Zürich.

Gehrig, R., M. Hill, B. Buchmann, D. Imhof, E. Weingartner, and U. Baltensperger, 2003: Verifikation von PM10-Emissionsfaktoren des Strassenverkehrs. Eidgenössisches Departement für Umwelt, Verkehr, Energie und Kommunikation / Bundesamt für Strassen, 203.

Gehrig, R., M. Hill, B. Buchmann, D. Imhof, E. Weingartner, and U. Baltensperger, 2003: Feldmessungen von verkehrsbedingten Partikelemissionen. ACP Workshop 2003, Strassenverkehr und Luftqualität, ETH Zurich, PSI Villigen.

Imhof, D., U. Baltensperger, E. Weingartner, R. Gehrig, and M. Hill, 2003: In-field verification of particulate emission factors of road traffic. 7th ETH Conference on Combustion Generated Nanoparticles, Zürich.

Imhof, D., E. Weingartner, U. Vogt, A. Dreiseidler, E. Rosenbohm, V. Scheer, R. Vogt, O. J. Nielsen, U. Corsmeier, M. Kohler, and U. Baltensperger, 2003: Vertical distribution of particulate and gaseous pollutants close to a motorway in Germany. European Aerosol Conference, Madrid, S1345-S1346.

Sturm, P. J., U. Baltensperger, M. Bacher, B. Lechner, S. Hausberger, D. Imhof, E. Weingartner, A. S. H. Prévôt, R. Kurtenbach, and P. Wiesen, 2003: Roadside measurements of particulate matter size distribution. Atmos. Environ., 37, 5273-5281.

Weingartner, E., U. Baltensperger, and D. Imhof, 2003: Aerosolpartikel-Grössenverteilungen an verkehrsexponierten Standorten. ACP Workshop 2003, Strassenverkehr und Luftqualität, ETH Zurich, PSI Villigen.

Weingartner, E., C. Keller, W.A. Stahel, H. Burtscher, U. Baltensperger, 1997: Aerosol emission in a road tunnel. Atmos. Environ. 31, 451-462.

Funding Agencies

This project is funded by the Bundesamt für Bildung und Wissenschaft Contract Nr. 99.0283-1 in the framework of the EU project ARTEMIS

Contacts

For further information please contact

André Prévôt or David Imhof

Links

Artemis - Gasphase and Aerosol Chemistry Group - Laboratory of Atmospheric Chemistry - PSI

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