Dominion and Manukau Rds cited as places where emissions of more concern.
Auckland's proposed Waterview motorway will be safer to live next to than existing city routes such as Dominion and Manukau Rds, a public health expert told a planning hearing yesterday.
Dr David Black, an Auckland University environmental and occupational medical specialist, told a Government-appointed board of inquiry assessing the Transport Agency's $1.7 billion proposal to build a new 4.5km partly tunnelled link and to widen the Northwestern Motorway that he foresaw no general health concerns.
"I can't say there are no health effects in the proximity from the burning of hydrocarbon fuels but there are roads around Auckland which are a concern," he said.
"This proposal is not a concern in the overall protection of public health."
Dr Black said Dominion and Manukau Rds were examples of urban routes where traffic running at uneven speeds, and stopping and starting, had "very significant effects from emissions".
Although motorways carried high-density traffic, it travelled at a relatively constant speed, and the diversion of vehicles to them from suburban streets would have "a positive environmental and health effect".
Dr Black acknowledged to Ross Dunlop, one of the five-member board chaired by Environment Court Judge Laurie Newhook, that regional air-quality targets for potentially minute and deadly particulates called PM2.5 were sometimes exceeded.
But he said that had far more to do with "the current vehicle fleet and our policy of not requiring emission control testing than it has to do with the design and location of our roads".
Pressed by Judge Newhook on how the community could be assured there would be no added risk to respiratory health from the motorway projects, he acknowledged that public fears were legitimate. "We are dealing with the discharge of something noxious and toxic," he said.
The judge noted that proposed emissions vent stacks at the Waterview and Owairaka ends of a pair of 2.5km motorway tunnels meant "we are dealing with the concentration of a few hundred discharges into one pipe".
But Dr Black said those discharges would happen above ground, without the tunnels. He acknowledged concerns by one family near a proposed motorway-to-motorway interchange at Waterview for the health of two of their children with immune deficiencies, but described that as a "special case" which he had arranged to investigate separately on a confidential medical basis.
The location of the vent stacks remained in contention at yesterday's hearing, with lawyers for the Eden Albert Local Board and community groups pushing for alternative sites at each end of the tunnels.
Transport Agency consultant planning leader Amelia Linzey accepted that extending the southern portals of the tunnels about 70m southeast of a proposed site and partially burying their ventilation buildings would be the best option from a social perspective, but said costs had to be balanced against funding for other projects.
Although she and other witnesses accepted moving the portals would clear a "chokepoint" in Allan Wood Reserve next to the Avondale motor camp and provide a greater continuity of remaining green space, the agency estimates the cost at $12.9 million.
The local board and groups such as Living Communities are also pushing for a 25m emissions venting stack at the northern end of the tunnels to be built on the opposite site of Great North Rd to Waterview Primary School, and its associated kindergarten, which the agency has agreed to move to a new site in Oakley Ave.
