Wellington's toxic tunnel breaches international standards

01:20, Sep 04 2009
Mt Victoria bus tunnel
The Mt Victoria bus tunnel.
Karori tunnel
The Karori tunnel.
Mt Victoria tunnel
The Mt Victoria tunnel.
Northland tunnel
The Northland tunnel.
Seatoun tunnel
The Seatoun tunnel.
The Terrace tunnel
The Terrace tunnel.
Wellington Airport runway tunnel
Wellington Airport runway tunnel.
Rachel Howes
Rachel Howes on her way through Mt Victoria Tunnel. Air quality tests show breaches of international standards.
Scott Gibbs
'Sometimes you've got to hold your hand over your mouth,' says Scott Gibbs, who walks through the Mt Victoria Tunnel every day.

Air quality in Wellington's Mt Victoria Tunnel has breached international standards.

The New Zealand Transport Agency says it is considering further air testing in the Mt Victoria and Terrace tunnels.

Improving air quality is also a goal of a broader safety overhaul planned for both tunnels, which has been allocated more than $7 million in the latest Government transport funding announcements.

A Niwa study for NZTA concludes that while air quality in the two tunnels has improved substantially since 2003, the Mt Victoria Tunnel still breached international guidelines in the latest tests.

During the study, carbon monoxide levels in the tunnel breached the World Road Association's guidelines for pedestrians twice over two months last year, as well as its stricter standards for workers about 2 per cent of the time.

Neither tunnel breached Niwa guidelines during the testing.

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Meanwhile, the Green Party and Mt Victoria residents say the tests - which focused on carbon monoxide and nitrogen dioxide - left out dangerous smaller pollutants.

Green Party co-leader Russel Norman - a resident of Hataitai, the suburb at the other end of the tunnel - said the US Environmental Protection Agency had warned about "particulate matter" from vehicle exhausts and the tests should have included it.

"The research they have conducted is flawed because it has not taken into consideration fine-particle pollutants that pose serious health risks."

Mt Victoria Residents Association spokesman Kent Duston said residents had been complaining about pollution and noise from the tunnel for decades.

Some people even dangerously tried to walk through the bus tunnel to avoid the fumes in Mt Victoria Tunnel, he said.

Rob Whight, NZTA state highways manager for Wellington, said the particulate tests could have been conducted, but there were no international standards for short-term exposure to compare them against.

Testing for the two gases was a priority and keeping their levels down would also reduce exposure to particulate matter, he said.

However, Mr Whight said the agency was considering further air quality tests. Investigation and design work for the tunnels' safety upgrades is due to start before the end of the year.

Pedestrians emerging from the tunnel yesterday mostly had not enjoyed their journey.

Rachel Howes, of Mt Victoria, said she walked through it about three or four times a week.

"It's terrible. It's really, really hard to breathe and you just get all the fumes."

Scott Gibbs, of Hataitai, walked through the tunnel every day.

"At peak hour traffic, it really sucks. You can actually taste the fumes when it's really bad. Sometimes you've got to hold your hand over your mouth."

But Simon Voysey, of Hataitai, who also did the trip most days, said the fumes did not bother him.

WORSE THAN BEIJING

Braving Mt Victoria Tunnel on foot is worse than walking through some of the most polluted cities in the world.

Niwa's carbon monoxide standard for pedestrians is 87 parts per million (ppm) for up to 15 minutes of exposure, but some international standards have a stricter standard of 70ppm. Here is how the tunnel measures up:

* 0.1ppm - background atmosphere level of carbon monoxide

* 0.5 to 5ppm - average level in homes without gas stoves

* 5.9ppm - Beijing marathon route before pollution crackdown last year

* 75ppm the highest recording in Mt Victoria Tunnel over two months last year

* 100-200ppm - the centre of Mexico City in the 1970s

* 7000ppm - car exhaust

The Dominion Post