Hunter Valley focus area

Two Hunter Valley stations recorded the highest number of exceedances in 2025, when comparing all stations across the broader NSW Air Quality Monitoring Network:

• 30 days at Warkworth, a smaller community station located near mining operations in the Upper Hunter region
• 27 days at Stockton in the Newcastle Local region. Air quality at this station is often heavily influenced by sea salt.

These 2 stations met national benchmarks 91.7% and 92.6% of the time, respectively. Wagga Wagga North (22 days) recorded the highest number of days above any standard at metropolitan and regional centre stations.

Both Stockton with 30.3 µg/m³, and Warkworth with 29.6 µg/m³, were the only 2 stations to exceed the PM10 annual benchmark.

Larger population centres

During 2025, air quality data from monitoring stations near the Hunter Valley’s larger population centres were analysed:

• Beresfield, Newcastle and Wallsend in the Lower Hunter region
• Carrington, Mayfield and Stockton in the Newcastle Local region
• Aberdeen, Muswellbrook and Singleton in the Upper Hunter region.

The key findings from 2025 are:

• The PM10 daily benchmark was exceeded on 30 days in 2025, compared to 42 in 2024. Excluding Stockton (high levels of sea salt), the benchmark was exceeded on 13 days, compared to 6 in 2024.
• The PM2.5 daily benchmark was exceeded on 5 days, all due to bushfire smoke in November and December in comparison to 2024, where this benchmark was exceeded once.
• The annual average benchmarks for both PM10 and PM2.5 were met at all stations, except for the PM10 annual average at Stockton (30.3 µg/m³).
• The ozone benchmark was exceeded on 2 days, once at Muswellbrook (heatwave conditions on 20 December) and once at Wallsend (bushfire smoke on 9 December).

For detailed particles data from the Hunter larger population centre stations, refer to the PM10 summary graph and the PM2.5 summary graph on the Particles page of this statement. For Stockton, see below.

Stockton

Particle levels at Stockton are often influenced by sea salt spray, due to the station’s proximity to the coast. This is particularly evident during the warmer months when onshore winds prevail. Due to the unique air quality conditions at the Stockton station, further details are provided in this section.

The key findings for the Stockton air quality monitoring station in 2025 were:

• Stockton met the national benchmarks and assessment goals for all gaseous pollutants, including ammonia (NH₃). The closest any gas level got to a benchmark or assessment goal was 95% for hourly sulfur dioxide.
• There were 27 days above the PM10 daily benchmark, compared to 41 in 2024. The maximum daily average during 2025 was 86.7 µg/m³ on 27 November 2025 due to sea salt.
• Stockton exceeded the daily PM2.5 benchmark on 3 occasions in 2025, compared to none being recorded in 2024. The maximum daily average during 2025 was 38.6 µg/m³ on 9 December due to bushfire smoke.
• Stockton exceeded the annual PM10 benchmark (30.3 µg/m³) but met the annual PM2.5 benchmark.

The Stockton PM10 pollution rose shows that the highest PM10 levels (shaded green) in 2025 occurred under north-easterly or south-easterly winds. These coastal winds, which are common in the warmer months, transport sea salt spray, which increases PM10 levels (Lower Hunter Particle Characterisation Study).

This figure shows pollution roses of hourly PM10 for 2025 at Stockton. Pollution roses show the wind direction and their associated pollutant levels. The colours along the bars indicate categories of pollutant levels, with green shades showing the highest PM10 levels. The length of each bar shows the percentage of time the wind blows from a particular direction.

Upper Hunter

Data for PM10 were analysed from all 14 air quality monitoring stations in the Upper Hunter Air Quality Monitoring Network as shown in the Upper Hunter PM10 summary graph.

The key findings for 2025 are:

• There were 40 days above the PM10 daily benchmark, compared to 30 days in 2024.
• Warkworth recorded the highest number of days (30 days) above the PM10 daily benchmark, compared to 25 days in 2024.
• Daily PM10 was highest at Warkworth on 6 December (91.3 µg/m³) due to bushfire smoke.
• All stations except Warkworth met the annual average PM10 benchmark (annual average of 29.6 µg/m³).

The bar chart shows the maximum PM10 daily averages (left), PM10 annual averages (centre), and days exceeding the PM10 benchmark (right), for each of the 14 stations in the Upper Hunter.

Note: Exceedance days have not been divided into exceptional and non-exceptional events, as the NEPM compliance goals are not applied to these smaller community, diagnostic or background stations.