Air quality is assessed against the standards defined in the Measure and the associated goals shown in Table 4. The goal of the Measure is to achieve the National Environment Protection Standards as assessed in accordance with the monitoring protocol to the extent specified in Schedule 2 of the Measure. The extent is expressed as a maximum allowable number of exceedances for each standard (shown in column four of Table 4).

The number of allowable exceedances associated with the standards has been set to account for unusual meteorological conditions. In the case of particles, allowable exceedances include exceptional events such as bushfires, hazard reduction burning (if authorised by state jurisdiction) or continental-scale windblown dust that cannot be controlled through normal air quality management strategies. Air quality monitoring data from each monitoring site are assessed against the Measure’s standards and the associated goals for each pollutant.

Compliance with the Measure requires that air quality standards are not exceeded more than the allowable number (as outlined in Schedule 2 of the Measure). Compliance with the Measure also requires that a minimum of 75 per cent of data are available for each quarter in the year. Regions are deemed to meet the Measure’s standards and goal if previous screening has shown that pollution levels are consistently below air quality standards and monitoring is therefore not required. In this way, lead is deemed to meet the Measure’s standards and goals, because lead was shown to be consistently below the Measure’s standards, due to the introduction of unleaded fuel in 1985. As a consequence, EPA stopped monitoring for lead in 2004.

The Measure’s goals for carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, PM₁₀, PM_2.5 and lead must be below the standards within the extent specified, such as taking into consideration exceptional events as described in the Measure. EPA uses a green, amber & red traffic light system to indicate compliance.

• Met– standard and goal achieved
• Not Met* – standard and goal not achieved due to insufficient data capture.
• Not Met – standard and goal not achieved.

Table 4: Air quality standards and goals in the Measure

2.1 Particles (PM_2.5)

In Victoria, PM_2.5 is assessed against a daily standard of 25 µg/m³, with a goal of zero exceedance days allowed per year, excluding exceptional events such as bushfires and authorised hazard reduction burning. PM_2.5 is also assessed against an annual standard of 8 µg/m³ as shown in Table 5. Table 6 shows the highest recorded concentration for each monitoring station. In 2020 there were multiple exceedances recorded on PM_2.5 instruments across EPA’s network. As a result, the standards and goal for PM_2.5 were not met. Most of the exceedances were due to major bushfire events in Quarter 1 (Q1; January and February 2020), with several exceedances also associated with hazard reduction burns and wood heater smoke in Quarter 2 and Quarter 3 (Q2 and Q3). There were also data losses at Alphington and Geelong monitoring stations for PM_2.5.

• At Alphington, there were 15 days where the standard was exceeded, however for the purpose of NEPM reporting only 7 days were reported. This was due to a failed flow audit in Q1 that meant that data was considered invalid, the data collected during this time included 7 exceedances caused by smoke from major bushfires that occurred in January 2020. A potential exceedance of the standard was also recorded on 4 October 2020, however this was identified during the data validation process as being due to pollen entering the sampling inlet, data collected for PM₁₀ at Alphington was significantly lower than the PM_2.5 reading, as a result, this day has been excluded from the validated dataset.**
• At Geelong, the main detector in the instrument failed, and as a result there was less data collected during Q1.

Table 5: PM_2.5 compliance data for 2020

Table 6: 24hr PM_2.5 highest and second highest concentrations for 2020

2.2 Particles (PM₁₀)

In Victoria, PM₁₀ is assessed against a daily standard of 50 µg/m³, with a goal of zero exceedance days allowed per year, excluding exceptional events such as continental scale dust storms. PM₁₀ is also assessed against an annual standard of 25 µg/m³ as shown in Table 7. Table 8 shows the highest recorded concentration for each monitoring station.

In 2020 there were multiple exceedances recorded across the PM₁₀ network, as a result, the standards and goal were not met. Most of the exceedances were due to major bushfire events in Quarter 1, with one exceedance at Footscray in Quarter 4 associated with strong winds and dust. There were also data losses for PM₁₀ at Footscray in Quarter 1 and Geelong in Quarter 2 and Quarter 4 for PM₁₀.

• At Footscray, a sensor fault in Quarter 1 was detected during routine audits. This meant that some data were invalidated back to the prior audit.
• At Geelong, EPA replaced the instrument in Quarter 2 which resulted in some data being invalidated. A temperature sensor fault in Quarter 4 also resulted in some data being invalidated.

Table 7: PM₁₀ compliance data for 2020

Table 8: 24-hour PM₁₀ highest concentration for 2020

2.3 Carbon monoxide (CO)

In Victoria, carbon monoxide is assessed against an eight-hour standard of 9.0 ppm, with one exceedance day allowed per year as shown in Table 9. Table 10 shows the highest recorded concentration for each monitoring station.

In 2020 there were no exceedances of the carbon monoxide standard. As a result, the standards and goal for carbon monoxide were met.

Table 9: Carbon monoxide compliance data for 2020

Table 10: 8-hour carbon monoxide highest and second highest concentration for 2020

2.4 Nitrogen dioxide (NO₂)

In Victoria, nitrogen dioxide is assessed against a one-hour standard of 120 ppb, with one exceedance a day allowed per year and an annual standard of 30 ppb, with no exceedances allowed as shown in Table 11. Table 12 shows the highest recorded concentration for each monitoring station.

In 2020 there were no exceedances of the nitrogen dioxide standards. As a result, the standards and goal for nitrogen dioxide were met.

Table 11: Nitrogen dioxide compliance data for 2020

Table 12: One-hour nitrogen dioxide highest and second highest concentrations for 2020

2.5 Ozone (O₃)

In Victoria, ozone is assessed against a one-hour standard of 100 ppb and a four-hour standard of 80 ppb, with one exceedance day allowed per year as shown in Table 13. Tables 14 and 15 show the highest recorded concentrations for each monitoring station.

In 2020 there were multiple exceedances recorded on ozone instruments across EPA’s network. As a result, with the exception of Alphington and Traralgon, the standards and goal for ozone were not met.

While there were no exceedances of the ozone standard recorded at Point Cook, the station did not meet the goal as there was less than 75% data capture in Quarter 1 and overall for the year. This was related to power supply issues at the site which required the site owner to replace a power transformer.

Table 13: Ozone compliance data for 2020

Table 14: One-hour ozone highest and second highest concentrations for 2020

Table 15: Four-hour ozone highest and second highest concentration for 2020