A report prepared for the NZ Transport Agency to measure the air quality effects of the Waterview Connection project shows that venting vehicle emissions from the tunnels 25 metres into the air will have a negligible effect on local air quality.
Principal project manager Clive Fuhr says air quality modelling in the report for 2016, the first year the tunnels are expected to be operating, shows that by removing vehicle fumes from street level, vented emissions will have less of an impact on local air quality than having the same traffic on local roads.
Parts of the project area are already subject to traffic emission effects from SH16 and to some extent from the busy local roads. The additional impact on air quality from the operation of the tunnel vents in the most sensitive locations is modelled to be very small – for example an increase of less than 0.3% for particulates at ground level and a considerably lower percentage increase for nitrous oxides, carbon monoxide and benzene.
“People have been naturally concerned about the potential environmental and health effects of tunnel emissions from the Waterview Connection project and we know we have to meet national air quality standards which are set to protect the most vulnerable. We hope this report will give the community confidence that this will be achieved, he said.
“People have told us they are concerned that venting tunnel emissions will mean poor air quality but the evidence is that tall vents are very effective at dispersing all pollutants including those for which there is no treatment method.”
“For this project the most evident air quality effects will be from surface roads at the interchanges and are not related to how tunnel emissions are managed. Nevertheless, national air quality standards will still be met.
He says the report, which was released today, will be presented to the community at a workshop at the Waterview Methodist Church, at 7pm on 23 October.
“Releasing the report in advance gives people time to read and understand it and come to the workshop with thoughts and questions.”
He said final decisions were yet to be made by NZTA on the management of vehicle emissions, the location of the vents or their height. Feedback from the workshop as well as the report will be relayed to the NZTA board to assist with its decision making on these issues.
Mr Fuhr said the project team was committed to engaging openly with the community on air emissions management and the release of the air quality effects report would enable everyone to have the same information.