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 type Pollutant / parameter Averaging period Units of measurement Limit / goal
External ambient CO 15 minutes PPM 87
External ambient NO2 1 hour PPM 0.125
External ambient NOx 24 hours µg/m³ 256
External ambient PM10 24 hours µg/m³ 50
External ambient Temperature at 2 metres 1 hour º N/A
External ambient Temperature at 10 metres 1 hour º N/A
External ambient Wind Direction 1 hour m/s NA

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 goal Traffic light status
If reading is less than 67% of limit/goal Good
If reading is greater than or equal to 67% and less than 100% of limit/goal Fair
If reading is greater than or equal to 100% of limit/goal Poor