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Air quality portal

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Frequently asked questions

Choose a question below to see the answer and find helpful links to more information.

Air quality monitoring

In NSW, the Department of Planning, Industry and Environment monitors, analyses and publishes information about air quality. They operate a comprehensive air quality monitoring network to provide you with accurate and up‑to‑date information about air quality. To find out more please visit www.dpie.nsw.gov.au/air-quality

Both state and federal governments are required to report against the six main air pollutants and our national standards for PM2.5 are one of the most stringent in the world.

Air pollution in Australia is measured by six main air pollutants; carbon monoxide, nitrogen dioxide, photochemical oxidants, sulphur dioxide, lead and particle pollution or particle matter (PM). PM is generally classified according to the size of the particles.

  • Particles less than 10 micrometres in diameter are called PM10,
  • Particles less than 2.5 micrometres in diameter are PM2.5,
  • Particles less than 1 micrometre in diameter are PM1,
  • Particles less than 0.1 micrometres in diameter are called ultrafine particles (UFPs).

It is important to note that PM10 includes PM2.5, PM1, and UFPs.

Sydney is a major international centre with residential, commercial, industrial, and natural occurrences such as bush fires, all contributing to air pollution. Motor vehicles are an important contributor to emissions, contributing 13 per cent of PM2.5, and 55 per cent of nitrogen oxides (which includes nitrogen dioxide (NO2) and nitric oxide (NO)). Other major contributors include wood heaters, which contributes 50 per cent of PM2.5, and industry – which contributes 18 per cent of PM2.5 and 13 per cent of oxides of nitrogen.

In NSW, the Department of Planning, Industry and Environment operates a comprehensive air quality monitoring network to provide you with accurate and up‑to‑date information about air quality. To find out more please visit www.dpie.nsw.gov.au/air-quality

In addition, air quality within major NSW tunnels is continuously monitored along the tunnel and at the ventilation outlet to control the ventilation system. This ensures the strict air quality limits outlined in the approval conditions are complied with at all times.

Since the Lane Cove Tunnel, air quality monitoring data is required to be made publicly available on the tunnel’s website, which is a requirement of the approval conditions. To find out more please visit:

  • Lane Cove Tunnel - https://www.lanecovetunnel.com/
  • M5 East - https://www.rms.nsw.gov.au/about/environment/air/tunnel-air-quality/m5-east/index.html
  • New M4 - https://www.linkt.com.au/sydney/using-toll-roads/about-sydney-toll-roads/westconnex-m4/tunnel-air-quality

Air quality regulation

The NSW Environment Protection Authority (EPA) regulates air quality and implements measures for managing and reporting air pollution. To find out more about the NSW EPA please visit: http://www.epa.nsw.gov.au/your-environment/air

Transport for NSW and private operators of future operating tunnels in NSW will be required to apply for an Environment Protection Licence (EPL) under the new requirements. Existing road tunnels in Sydney will also be required to apply for an EPL. Read more about the new regulatory requirements by clicking here.

Sydney’s air quality

The Office of Environment and Heritage (OEH) operates an ambient air quality monitoring network with 17 monitoring sites across Sydney to provide the community with accurate and up-to-date information about air quality. In addition to the OEH network, Roads and Maritime deploys ambient monitoring stations to collect data for air quality assessments and has collected air quality data from 25 locations since 2013.


You can view Sydney’s hourly air quality readings here http://www.environment.nsw.gov.au/AQMS/aqi.htm, for additional information on the air quality monitoring network visit http://www.environment.nsw.gov.au/topics/air.

Despite there being more cars on the road, a number of initiatives and technological developments have resulted in substantial reductions to vehicle emissions in the Sydney region over the past three decades. The number of cars is expected to further increase as the population of Sydney continues to grow, although total emissions from motor vehicles are set to fall further over the next 10 years due to the continued phasing out of older vehicles.

According to the World Health Organisation, Sydney’s air quality is good by national and international standards. The exception is during exceptional events such as bushfires. Explore the data here.

Sydney is a major international centre with residential, commercial, industrial, and natural occurrences such as bush fires, all contributing to air pollution. While motor vehicles are an important contributor to emissions, it should be acknowledged there are other significant sources of emissions. To find out more, download our latest factsheet.

Road tunnels can improve air quality for surrounding communities by removing vehicles from the surface road into an underground tunnel.

Motorists experience a smooth motorway to travel on, rather than being in congested, stop start traffic. This means less sudden braking, less wear and tear on vehicles and a reduction in emission levels on local roads.

With the expected increase in electric vehicles and other cleaner vehicle technologies over the next decade, we will see ongoing emission reductions from motor vehicles, even with more vehicles travelling on our roads.

Tunnel ventilation systems

Tunnel ventilation systems work by ensuring sufficient air flows within the tunnel to meet air quality requirements. In NSW, tunnels longer than one kilometre also have ventilation outlets, which eject tunnel air high into the atmosphere, through a combination of buoyancy and speed. Once in the atmosphere, the ejected tunnel air dilutes hundreds of times as it mixes with the surrounding air and becomes indistinguishable from background levels.

Ventilation outlets are vertical structures with large fans at their base designed to eject tunnel emissions high into the atmosphere, ensuring they are dispersed and diluted so there are no measurable effects on local or regional air quality.Each outlet is custom designed to take account of local tunnel air flows, terrain, surrounding buildings and weather to ensure effective dispersion under all conditions.

Our tunnels are required to meet stringent air quality standards using state-of-the-art ventilation and tunnel design.

Studies have found that filtration systems would not provide any measurable improvement to the air quality in the surrounding community, and as such, there is little to no health benefit for surrounding communities in installing filtration and air treatment systems in such tunnels. To find out more you can download the Initial Report on Tunnel Air Quality from the Advisory Committee on Tunnel Air Quality.

Elevated ventilation outlets are very effective at ejecting tunnel air high into the atmosphere through a combination of buoyancy and speed. This occurs by the warmer tunnel air (heated by vehicles using the tunnel) being ejected upwards at speed through the outlet by axial fans. This warm air continues to rise high into the atmosphere through natural buoyancy as it is warmer than the surrounding air.

Once in the atmosphere, the ejected tunnel air dilutes hundreds of times as it mixes with the surrounding air before mixing down to ground level resulting in little, if any, change to the quality of the air people breathe.

The tunnel ventilation systems are designed to operate effectively under all traffic and weather conditions.

Modern tunnel ventilation design ensures the operation of our tunnels meet strict air quality requirements set by the Department of Planning, Industry and Environment and the Environment Protection Licence issued by the Environment Protection Authority.

Our modern tunnels are designed to achieve:

  • strict in-tunnel air quality
  • no emissions from portals
  • emissions from ventilation outlets that result in little, if any, change to the quality of the air people breathe.

Air quality within major NSW tunnels is continuously monitored along the tunnel and at the ventilation   outlet to control the ventilation system. This ensures the strict air quality limits outlined in the approval conditions are complied with at all times.

The EPA regulates the ventilation outlets for all current and future operating motorway tunnels to ensure they meet air quality limits.

Tunnel ventilation systems generally work most efficiently and effectively when the ventilation outlet is positioned near the exit ramp. This is why the ventilation outlets for modern tunnels are located near tunnel exit ramps.

All Sydney road tunnels have management plans that involve monitoring in tunnel air quality 24-hours a day and they must comply with limits outlined in the approval conditions set by the Department of Planning and Environment.

The In-tunnel Air Quality (Nitrogen Dioxide) Policy sets the compliance standard of 0.5 ppm, as a 15 minute rolling average for all new tunnels more than one kilometre long. This limit sets the benchmark in Australia and compares favourably to the international in-tunnel nitrogen dioxide design guidelines which range between 0.4 ppm and 1 ppm.


Visit our website to find out more: http://www.rms.nsw.gov.au/projects/key-build-program/building-sydney-motorways/sydney-tunnels/index.html#In-tunnelAirQuality(NitrogenDioxide)Policy

Demolition

State-of-the-art pulverisers and shears are jaw-like excavator attachments. They crush and cut away at the walls and floors of buildings during demolition.

We use them because they make significantly less noise than hydraulic hammers.

TBM dive site

Two tunnel boring machines (TBMs) will be launched at the Marrickville dive site. It will be a tunnelling support site and provide the services TBMs need to build the tunnels such as grout, water, power and spoil removal.

  • Noise wall construction
  • Noise wall construction
  • Noise wall construction

Noise walls

Noise walls are built at some sites to reduce the impact of noisy works on the community.

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Air quality - have your say

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We will answer your enquiry as soon as we can. To find out more about Roads and Maritime, please visit: http://www.rms.nsw.gov.au/

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Roads and Maritime Services

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PM2.5 pollution charts and maps data source: 'Ambient Air Pollution Database', World Health Organisation, 2018. For more information and full disclaimers regarding data collection, measurement, estimations and limitations view the WHO Air Pollution web page .

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Community consultation

We will be carrying out a community consultation where you can learn about the Gateway to the South works, ask questions about the project and give your feedback. Please feel free to drop in at the following locations:


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Wednesday 15 February 4:30pm-7:30pm


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Terms of use

This internet site is designed to provide educational information on air quality across NSW. Use of this internet site is subject to these Terms of Use.

Roads and Maritime Services makes no representations or warranties in relation to the accuracy or completeness of the information contained within this internet site or displayed by it, or the accuracy or completeness of any data (or other outcome printed or manifested in any other way) as a result of its use.

The internet site, or any data or other information displayed by the internet site is in no way binding on Roads and Maritime and may not be appropriate for your specific needs or circumstances.

The internet site may contain links to third party internet sites that are not under Roads and Maritime’s control and which Roads and Maritime does not sponsor or endorse. By linking to a third party internet site Roads and Maritime is not accepting responsibility for the content of that internet site or your use of it and makes no warranty as to its suitability. Use of any third party internet site is subject to the terms of that internet site.

Roads and Maritime makes no representation or warranty that the internet site will be continuously available or free from any delay in operation or transmission, virus, communications failure, internet access difficulties or malfunction in hardware or software. Roads and Maritime also reserves the right at any time and without notice to discontinue or modify the internet site in whole or part.

Subject to any responsibilities implied by law and which cannot be excluded, Roads and Maritime is not liable to you for any losses, expenses, damages, liabilities and claims whatsoever, whether direct, indirect or consequential, arising out of or referrable to the use of this internet site or its discontinuance, howsoever caused (including your reliance on any inaccurate or incomplete information or data contained within or displayed by the internet site) whether in contract, tort (including negligence), statute or otherwise. Roads and Maritime’s liability for breach of a condition or warranty implied by law which cannot be excluded is limited to the extent possible to the re-supply of the internet site.

What is PM10 and PM2.5?

PM2.5 are tiny particles of particle matter, thirty times smaller than a strand of human hair.

Air pollution in Australia is measured by six main contributors; carbon monoxide, nitrogen dioxide, photochemical oxidants, sulphur dioxide, lead and particle pollution or particle matter (PM). PM is generally classified according to the size of the particles.

  • Particles less than 10 micrometres in diameter are called PM10,
  • Particles less than 2.5 micrometres in diameter are PM2.5,
  • Particles less than 1 micrometre in diameter are PM1,
  • Particles less than 0.1 micrometres in diameter are called ultrafine particles (UFPs).

It is important to note that PM10 includes PM2.5, PM1, and UFPs.

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