Air quality and noise monitoring

With construction on SRL East underway, we're working closely with residents and businesses to manage potential impacts. We have been carefully planning our works to reduce disruption and minimise impacts on the local community.

Residents and businesses are being offered a wide range of support measures while we build this city-shaping project. As far as possible, noisy works will be limited to normal working hours, ensuring residents and businesses know when works are happening and are offered appropriate support.

A 12-month trial to publicly report real-time air quality and noise monitoring data is underway, with environmental monitoring equipment installed at the Burwood tunnel access excavation site. This trial has been developed as a result of the SRL East Environment Effects Statement in response to feedback from local councils and the community.

Contractors develop environmental management plans that detail ways to avoid, reduce, or manage environmental impacts. These may include enclosing noisy equipment or selecting the quietest available equipment to complete works.

Regular inspections, monitoring and ongoing auditing will be used by contractors on site to control noise and dust levels. Our construction teams monitor the performance of control measures so they can respond swiftly to any irregular changes. For example, if a plume of dust occurs due to unforeseen weather conditions, the construction team may respond by watering the dust source to reduce emissions.

Limitations of publishing real-time monitoring data

Real-time monitoring is a useful tool on construction sites but does have some limitations when the raw data are viewed on this website, before it has been analysed:

The data are yet to be reviewed and interpreted by acoustic and air quality specialists to determine the cause of the noise or dust.
The monitors that measure dust concentrations and noise are located within the construction site close to the nearest homes. However, the measured levels at the nearest homes and beyond are usually less than what is measured by the monitor. This is due to the monitor being located closer to the noise and dust source ensuring security of the loggers, and it may not account for controls in place to minimise the levels at residential properties.
Monitors have been placed to provide an accurate representation of the air quality and airborne noise at each site, however monitors may need to be moved as works progress.
Breaks in data availability may occur due to sensor outages, instrument errors, technical issues or removal of sensors during non-working periods to ensure the security of the equipment.
Sometimes monitors do not provide the correct information when humidity is high (e.g. during fog). For more information, see how EPA monitors air quality.

Understanding noise data

The following tables explain how contractors use airborne noise reference and guideline levels to manage potential impacts. These are not compliance levels, but are used by contractors to trigger an investigation into the source of the noise (as it may not be as a result of the construction works) and tailor their response. The airborne noise reference levels (shown in the third column) are based on the background levels (shown in the second column) provided in the SRL East Environment Effects Statement (EES), recorded at the closest location to where the real time noise monitors will be positioned.

Background noise levels are measured using the L_A90 metric as it measures the underlying noise level occurring 90 per cent of the time. This excludes intermittent noise like a truck passing, while construction noise is measured using the L_Aeq metric as it better measures the varying noise sources from different construction activities.

Contractors design on-site mitigation measures to reduce noise below these reference levels, so far as reasonably practicable (refer EPA Guideline 1856). At times, even with all controls in place, it may not be possible to achieve these reference levels and then off-site mitigation measures need to be applied in accordance with SRLA’s Residential Support Guidelines – such as offering respite measures and residential relocation when appropriate. The fourth column includes the range of guideline levels at which different mitigation measures will be applied. Further information on how they can be applied is found in the Residential Support Guidelines.

Reference and Guideline Noise Levels at Heatherton

Time period	Heatherton (EES monitoring location STB U3) Background noise level L_A90	Heatherton Background +10dB Adopted residential reference levels L_{Aeq, 15 mins}	Heatherton Residential Support Guidelines Guideline levels L_{Aeq, 15 mins}
Normal working hours	51 dB	61 dB	> 61 dB > 75 dB
Weekend/evening work	44dB	54 dB	> 49 dB > 54 dB
Night	40 dB	Noise inaudible within a habitable room of any residential premises	> 40 dB > 45 dB > 55 dB > 65 dB

Reference and Guideline Noise Levels at Burwood

Time period	Burwood (EES monitoring location BUR U1) Background noise level L_A90	Burwood Background +10dB Adopted residential reference levels L_{Aeq, 15 mins}	Burwood Residential Support Guidelines Guideline levels L_{Aeq, 15 mins}
Normal working hours	43 dB	53 dB	> 53 dB > 75 dB
Weekend/evening work	43 dB	53 dB	> 48 dB > 53 dB
Night	37 dB	Noise inaudible within a habitable room of any residential premises	> 37 dB > 42 dB > 55 dB > 65 dB

Noise data are measured in A-weighted decibels, averaged over a 15-minute period and is shown on the graph below in 15-minute intervals.

Understanding air quality data

The purpose of air quality monitors is to measure the concentration of small particles in the air near the construction site. The particles that have the potential to impact human health are known as PM₁₀. Environment Protection Authority (EPA) monitoring stations measure background concentrations of pollution that already exist in the air within the surrounding area. The EPA monitoring station at Dandenong is used as the representative control site for Heatherton, and the EPA monitoring station at Alphington is used as the representative control site for all other SRL work sites.

EPA Guideline 1961: Guideline for assessing and minimising air pollution establishes 80 µg/m3 (1-hour average) as an adaptive level requiring contractors to respond when conditions change on the site. The below graph shows PM₁₀ (averaged over 1 hour).

From these data, the Contractor reviews 24-hour average concentrations for comparison with the state air quality objectives published by EPA. The 24 hour averaged data are available in the monthly verified air quality reports.

Heatherton

Both Initial Works and Early Works are being undertaken concurrently at Heatherton. The proximity of these works means that there is a possibility that Initial Works are contributory factors to air quality and noise conditions at the site. Initial Works are not subject to the SRL Environmental Management Framework.

The air and noise monitoring does not include monitoring related to asbestos removal, which is monitored and reported on separately. Monitoring for asbestos particles in the air has consistently found that levels are within a safe and allowable range.

Burwood

There are likely to be a range of factors that contribute to isolated spikes in dust levels. The exact cause of a specific spike in noise or air quality will be reviewed and interpreted by acoustic and air quality specialists to determine the cause and to enable appropriate mitigation measures to be implemented as quickly as possible.

Glossary

dB

A unit of measurement used to express sound level. It is based on a logarithmic scale which means that a sound that is 3 dB higher has twice as much energy. We typically perceive a 10 dB increase in sound as a doubling of loudness.

A-weighted

Refers to a noise level where a weighting filter has been applied such that the noise level represents how people typically perceive sounds at different frequencies.

LAeq 15 mins

A-weighted Equivalent Noise Level - The energy-averaged ‘A-weighted’ noise level over a measurement time of 15 minutes.

The L_Aeq metric is commonly used to describe the level of noise from a source under assessment. The noise levels from a source may vary with time and the L_Aeq metric represents the steady A-weighted sound level that would have the same total energy as the time-varying noise level.

The L_A90 metric refers to the A-weighted level of noise exceeded for 90% of a given time period, such that it excludes short-term noise from intermittent traffic, insects, animals and the like. The L_A90 represents the underlying noise level at a given location and is therefore commonly used to describe the background noise level in an environment.

μg/m3

Micrograms per cubic metre is a unit of measurement used to measure the concentration of air emissions (micrograms) per volume of air (cubic metre).

PM10

Particulate matter with an aerodynamic diameter of 10 micrometres (µm) or less. PM₁₀ particles are small enough to have a potential impact on human health

For further information please contact our customer service team on 1800 105 105. If you require a translator or interpreter, you can contact us on 03 9209 0147.