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Goals and limits

Monitoring types

The air quality goals and criteria for pollutants monitored at the Transurban M5 East tunnel ambient monitoring sites are based on the Conditions of Approval. The air quality goals and criteria are shown in the table below:

Monitoring typePollutant / parameterAveraging periodUnits of measurementLimit / goal
External ambientCO15 minutesPPM87
External ambientNO21 hourPPM0.125
External ambientNOx24 hoursµg/m³256
External ambientPM1024 hoursµg/m³50
External ambientTemperature at 2 metres1 hourºN/A
External ambientTemperature at 10 metres1 hourºN/A
External ambientWind Direction1 hourm/sNA

Traffic light status

We have developed a traffic light status for air quality based on the same values the Office of Environment and Heritage (OEH) use to display their Air Quality Index (AQI). The AQI is a scale of air pollution that helps people understand air quality and modify any activities if pollution levels are high. For further detailed description and explanation of the OEH AQI visit Understanding air quality for the Office of Environment and Heritage.

The traffic light status of each pollutant is shown in the 'Current snapshot' table for External Ambient, In-tunnel and Ventilation Outlet and it is based on the hourly reading relative to the limit or goal.

Percentage of goalTraffic light status
If reading is less than 67% of limit/goalGood
If reading is greater than or equal to 67% and less than 100% of limit/goalFair
If reading is greater than or equal to 100% of limit/goalPoor