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NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
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Pacific 2001: Cassiar Tunnel Study – Emission Rate Uncertainty Assessment
Lisa A. Graham and Diane Dey
Environment Canada, Emissions Research and Measurement Division, Ottawa, Ontario, Canada K1A 0H3
Vehicle emission sampling was conducted at the Cassiar Tunnel in Vancouver during August 9-15, 2001. This was a 7-day study with 3 sampling periods each day. The goals of the Cassiar Tunnel Study were:
- To obtain accurate mass emission rates for a wide range of pollutants emitted from motor vehicles.
- To compare the emissions measured at the tunnel (>150,000 vehicles over 7 days) with chassis dynamometer measurements of a limited number of vehicles (70 vehicles over 5 weeks).
- To obtain current emission profiles for on-road vehicles for use in source apportionment studies.
A preliminary assessment of the sources and magnitudes of the various uncertainties affecting the emission rate calculations from the tunnel study measurements will be presented. The uncertainty assessment methodology used follows the structure required by ISO 17025 accreditation.