Air monitoring, air quality and dust

The program focuses on monitoring PM_2.5 and PM₁₀ because they indicate smoke and dust levels, which are expected to be high. The equipment for these measures is compact and easy to place in suitable locations. The one large station at Primula Avenue measures all pollutants, including carbon monoxide and nitrogen dioxide, which EPA considered adequate to represent the general ambient air quality.

No. These stations have been strategically located to measure the air quality before and after the tunnel is operating.

The locations of the air monitoring stations are:

• Full station: 14-16 Primula Avenue (beside freeway just off Millers Road, Brooklyn)
• PM₁₀ and PM_2.5 only stations:
  • Barbara Beyer Reserve, Yarraville
  • 51 Francis Street, Yarraville
  • Millers Road and Nolan Ave, Brooklyn, on corner not far from Full station
  • Woods Street near Avoca St, Yarraville.
    

No. There is no program for EPA to review PurpleAir community monitors. However, the community can use their own PurpleAir monitors to get a general indication of air quality at a specific location.

The current air monitoring program is required to continue up to 5 years of tunnel operation. A review will be undertaken during this period to determine the air monitoring program required.

Downwash is when wind is deflected downwards by a building or other structure that can push pollutants down to ground level.

The effect of downwash on the stack air emissions to ground level may occur during specific weather conditions for limited periods near the stack.

The air modelling incorporated downwash effects from the stack in its assessment.

We are actively considering options to locate sensors that measure PM_2.5 and nitrogen dioxide near the southern and northern portables at the Edwards Reserve and Yarraville Gardens sites, respectively, to validate modelling predications in relation to negligible downwash effects close to the stacks.

Nevertheless, while EPA maintains that the existing monitoring network will adequately characterise general ambient air quality, the additional monitors also respond to community concerns about potential downwash effects.

Yes, ventilation filtration was considered during the Environment Effects Statement process overseen by the Minister for Planning, and during the Works Approval application assessment by EPA.

The design and height of the ventilation stacks and a high-speed extraction system to push emissions high into the atmosphere are designed to adequately disperse tunnel emissions and minimise any ground-level impacts.

The tunnel ventilation structures and operation are current practice in Australia.

The decision was based on:

• the air quality modelling and associated air quality impact assessment concluded that tunnel ventilation structures and operations have been optimised to ensure the air quality impacts at the ground level are low and minimised
• a human health risk assessment concluded that air quality changes would not result in measurable adverse health effects
• he Department of Health and Human Services stated that the air impacts from tunnel emissions were below health-based guidelines and posed a low risk to human health
• local air monitoring data from the CityLink, East Link and Sydney tunnels showed low impacts from tunnel ventilation systems
• trial filtration systems in New South Wales did not demonstrate improvement in local air quality.
  

The West Gate Tunnel Project is best placed to provide costings for a stack ventilation filtration system.

EPA issued a Works Approval with conditions requiring:

• the system's final design to include the capacity to retrofit ventilation filtration if necessary
• continuous monitoring of in-tunnel air will continue during the tunnel’s operation
• continuous monitoring of ventilation stack emissions during the tunnels tunnel's operation
• independent stack testing of ventilation stack emissions to audit and verify continuous monitoring
• independent analysis to verify emissions remain within air emission discharge licence limits.
  

• Yes. Air monitoring data will also be analysed to identify stack ground level contributions. An independent detailed Air Quality Impact Assessment (AQIA) and Human Health Risk Assessment (HHRA) will be undertaken to evaluate the impacts of tunnel emissions.
• This involves air quality modelling, using local weather data and a minimum of 12 months of measured stack emission monitoring data. These data will determine the effects and additional impacts at ground level from the stack emissions.
• The results of the risk assessments, as well as the effectiveness of the current control measures and any future needs for control measures, will be used to determine if any further controls, including filtration, are necessary (and what they might be).
  

No tunnels in Australia have ventilation stacks with filters.

The final design of the air ventilation stacks has a provision to include the ability to retrofit ventilation filters if required.

An independent detailed Air Quality Impact Assessment (AQIA) and Human Health Risk Assessment (HHRA) will be conducted. This involves air quality modelling, using local weather data and at least 12 months of measured stack emission monitoring data. This data will determine the levels contributed to ground level by the stack emissions.

Air monitoring data will also be analysed to identify stack ground level contributions. The measured ambient background air quality and the added stack emissions will be compared to Environmental Reference Standards and other relevant air pollution and health standards in the AQIA and HHRA.

The results of the risk assessments, as well as the effectiveness of the current control measures and any future needs for control measures, will be used to determine if filtration is necessary.