Victoria’s air monitoring plan for the assessment of air quality against the Measure was first approved in February 2001 by national, state and territory ministers on the National Environment Protection Council. Data presented in this report have been produced in accordance with the monitoring plan, with exceptions noted where required.

1.1 Monitoring stations

The Measure requires EPA to monitor the pollutants: carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), sulfur dioxide (SO₂), particles less than 10 micrometres (μm) in diameter (PM₁₀), and particles less than 2.5 μm in diameter (PM_2.5). EPA no longer monitors for lead, as ambient concentrations in Victoria have decreased significantly, due to the phase out of leaded petrol.

Eight regions are defined in Victoria’s air monitoring plan. These are:

• Port Phillip and Latrobe Valley regions, which have Measure-compliant monitoring stations
• Ballarat, Bendigo, Shepparton, Warrnambool and Mildura, where campaign monitoring was previously conducted
• Wodonga, where data from monitoring at Albury, New South Wales was used.

EPA’s 2020 Measure-compliant monitoring stations are shown in Figure 1 and Figure 2. The monitoring stations, pollutants monitored, and site types are summarised in Table 1. Site types are defined in the Measure as ‘generally representative upper bound for community exposure’ and ‘population-average sites’. EPA also has trend stations which provide data on the long-term trends in air pollution over many years. The types of communities covered by each monitoring station (known as the ‘exposed population’) is described in the ‘location category’ column in Table 1.

Figure 1: Defined regions and population density in Victoria

Figure 2: Defined regions and population density in Port Phillip region

Table 1: EPA NEPM monitoring stations and parameters

1.1.1 Implementation of the monitoring plan

EPA continually evaluates Victoria’s air quality monitoring program to determine which sites and pollutants need to be monitored. Stations are located and set up according to the Australian Standards (Table 2). Generally, EPA’s air monitoring stations have remained stable over the years, although changes to the network are made as needed. Recent changes include:

• A PM_2.5 monitoring station was established in the Melbourne CBD in 2017.
• A PM_2.5 monitoring station was established in Bendigo in 2020. Data from this station are not included in this report as it is a campaign station. Data from this station are available on EPA AirWatch.
• A PM_2.5 monitoring station was established in Campbellfield in 2020. Data from this station are not included in this report as it is a campaign station. Data from this station are available on EPA AirWatch.
• In mid-2019, the Altona monitoring station was temporarily shut down pending relocation to another site, a new site was established at a nearby location in late 2020.

1.1.2 Screening procedure

Victoria’s air monitoring plan outlines how EPA may use screening procedures to demonstrate whether concentrations of pollutants are consistently below the standards in the Measure. If these screening procedures are satisfied, monitoring may not be required, or may be conducted at fewer locations. Screening procedures conducted in accordance with the Measure have been satisfied a number of for Victorian regions. EPA did not monitor air quality at Ballarat, Shepparton, Warrnambool, Wodonga and Mildura in 2020 as previous monitoring campaigns in these areas showed that pollutant levels were expected to be consistently below the relevant standards.

1.2 Monitoring and reporting methods

Victorian monitoring is conducted in accordance with the Australian Standards as shown in Table 2 and Table 3. Data not meeting the requirements of these Standards and EPA’s quality assurance procedures were identified as invalid and not included in this report. Tapered Element Oscillating Microbalance (TEOM) PM₁₀ data included in this report have been adjusted according to the approved procedure outlined in Technical Paper No. 10 – Collection and Reporting of TEOM PM₁₀ Data 5, using the temperature dependent formula with a constant value of K equal to 0.04. The resulting adjustments vary from no change at daily average temperatures at or above 15°C, to an increase of 40% at a temperature of 5°C. Particle concentration units of μg/m³ refer to volumes at 0°C and one atmosphere of pressure.

1.2.1 NATA status

As of February 2016, EPA outsourced monitoring for PM₁₀ and PM_2.5 using the Hivol and Partisol gravimetric methods to Golder Associates (NATA accreditation Number 1910). All other methods currently used by EPA for performance monitoring are covered by its National Association of Testing Authorities (NATA) accreditation (Number 15119) except for PM_2.5 using Beta Attenuation Monitors (BAMs). EPA was reaccredited by NATA in 2020. EPA is working to incorporate monitoring for PM_2.5 using BAMs as part of its NATA accreditation. The method is in use and all technical elements have been completed, and is due to be assessed at an upcoming NATA audit. Table 2 shows compliance with AS/NZS 3580.1.1:2016 for the siting and operation of each air monitoring station.

Table 2:  EPA NEPM monitoring stations siting compliance with AS/NZS 3580.1.1–2016

Table 3: EPA NEPM monitoring methods