Q&A – West Gate Tunnel Ventilation Stacks

Q: What are the expected traffic volumes in the tunnel?

Estimates are for 67,000 vehicles each day including 16,000 daily trucks.

Q: Who has recommended that filtration be installed into the West Gate Tunnel?

• The State Government appointed an Inquiry and Advisory Committee who assessed the project’s Environmental Effects Statement (EES) in 2017. They noted the area’s poor air quality and said that “the project should aim to contribute to an improvement in that situation”. All of the health and air quality experts who submitted to the EES process recommended filtration.

• The Inner West Air Quality Community Reference Group, who were commissioned in 2019 by State Government to provide advice to State Government on air pollution mitigation, including the feasibility and relative importance of tunnel filtration for the West Gate Tunnel Project.

• Maribyrnong Council in their comprehensive 2022 Air Quality Improvement Plan.

• Hobson’s Bay Council in their 2017 EES submission as well as in a formal motion in 2024, calling on Government to “install filtration on the chimney stacks of the West Gate Tunnel Project to protect the health and wellbeing of all Hobsons Bay residents”

Q: What is the State Government’s position on filtration?

The Government has committed to build the ventilation structures to allow for retrofitting of filtration in the future “if needed”. But without a defined trigger point at which this will be required, we do not believe it will ever happen. If a decision is made, and filtration is installed, harm would have already been done.

The decision to build the stacks to allow for retrofitting was the recommendation from the EPA. However, this recommendation was made in 2017 when the EPA was still operating under the old Environment Act. New laws, implemented in 2021, state that the EPA must operate with a prevention-based approach to environment and health protection. The decision to not filter unless harm has been caused is a clear example of old school decision making that is not considered appropriate or lawful anymore.

Q: Is the community already impacted by air pollution?

A 2020 study looked at health outcomes in three inner west municipalities, focussing on diseases for which air pollution can be a substantial contributory factor. It showed that the Cities of Maribyrnong and Hobsons Bay in particular have rates of hospitalisation substantially higher than national averages for many diseases strongly linked to air pollution. Maribyrnong had the worst cardiorespiratory outcomes across all metrics, including the highest rate of stroke in Victoria, despite having a younger than average population. Maribyrnong also has the highest hospital admissions for respiratory ailments in Victoria for young people aged 3 to 19 at a rate that is 70% above the Victorian average.

Hospital admissions for heart failure, lung cancer incidence and premature mortality by chronic obstructive pulmonary disease are also much higher than the national average in both municipalities. No other known risk factors for these diseases exist other than poor air quality.

Q: Won’t removing trucks off residential streets fix the problem?

Removing trucks off many of the residential streets will make a significant improvement in air quality for much of the area. However those living near the ventilation stacks will at times see a reduction in air quality, particularly when certain weather events occur. One of these types of weather events is an inversion layer, when pollution is trapped at ground level. Due to climate change we are already seeing these occur in Melbourne more frequently and for longer, resulting in days of extremely poor air quality. Being able to capture up to 90% of pollution from all of the vehicles using the tunnel provides a unique opportunity to remove those pollutants from the air shed. Why not take this opportunity to further reduce the air pollution exposure in a community already significantly impacted!

Q: Won’t the pollution be dispersed high up into the air?

Dispersal of pollutants via stacks is not the same as removing the pollutants. The emissions from the stacks are predominantly vehicle exhaust, an especially noxious subset of particulate matter that produces health risks at even minimal levels. Given that the community’s health is already compromised, mitigation measures such as filtration are important to actually remove the pollution from the airshed. Any reduction in vehicle exhaust emissions, however small, will result in public health gains. As mentioned, inversion layers are becoming denser and more frequent and no dispersion will occur on these days.

Q: Are the West Gate Tunnel vent stacks world’s best practice?

No, tunnels around the world are filtered specifically to protect surrounding residents from vehicle emissions. Countries that filter their road tunnels include Spain, Italy, France, Germany, Netherlands, Hong Kong, Japan and South Korea.

Q: Haven’t air monitoring stations been strategically placed around the projects area to ensure that air quality remains within safe limits?

The West Gate Tunnel will monitor air quality near the tunnel for only five years after the tunnel opens. The community’s opportunity to know whether pollution is increasing, and if retrofitting is required, will be compromised after this time. The data is not published in a way that is useful or informative to the community and the EPA does not have automatic access to this project monitoring data.

The government’s line of “within safe limits” is vague and meaningless to a community who lives daily with air pollution above WHO standards. Most worryingly, there is actually no monitor located near the Southern portal!

Q: Isn’t it too late now to install filtration?

It’s not too late if government decides now is the right time to protect human health. Installation should be an easy process as the ventilation stacks have been designed for retrofitting. Now however is the last chance to influence the project before it opens in late 2025. MTAG is working with Environmental Justice Australia, to pressure the EPA, to hold a ‘Conference of Interested Persons’ to hear new evidence on why the vent stacks must be filtered before they issue an operating license to Transurban. We cannot afford to not take this last chance.

Q: Aren’t truck emissions improving?
Australia’s truck fleet is amongst the oldest in the OECD. More than half are Euro III or older, which would not be allowed in most developed countries. We have a severe lack of regulatory, policy or market forces to improve the aged truck fleet.

A recent report by Austroads found that these old trucks are causing around $200 million in annual pollution-related health costs in Australia and these health costs are predominantly occurring in urban areas near ports. While governments in other countries have enacted measures to upgrade these old trucks, Australia hasn’t. A recent program by the Victorian Government, Modernising the truck fleet has seemingly stopped without any trucks being upgraded. We do not believe the $20,000 offered to truck operators to upgrade was anywhere near enough to be successful.

It has been estimated that at the current rate of fleet renewal, it will take ten years to reduce Australis average truck age by four months, from 14.8 to 14.4 years. We absolutely cannot rely on Australia’s truck emissions improving, with any gains well and truly negated by an expected doubling of container movements by 2050.