The season at a glance

Air quality was below national benchmarks on 79 of 90 days (87.8% of the season). Bushfire smoke and local dust contributed to the 11 exceedance days.

What affected air quality

Bushfire smoke – Seven exceedance days were linked to bushfires. Five occurred between 1 and 9 December 2025, and two on 31 January and 1 February 2026. On 31 January, 12 sites recorded exceedances, including Extremely Poor at Singleton and Camberwell. Singleton also recorded an ozone exceedance that day.

Local dust – Five sites recorded PM10 exceedances during summer: Singleton NW, Camberwell, Maison Dieu, Wybong and Jerrys Plains. Nearby mining activity likely contributed to this.

Other pollutants – Nitrogen dioxide and sulfur dioxide remained below national benchmarks throughout the season.

Across the network – Four stations each recorded the highest number of exceedances in summer, with four days each. Merriwa was the only station that did not record any exceedances.

Data coverage – Warkworth PM10 data was unavailable throughout summer due to an instrument fault. PM10 levels at Warkworth likely exceeded the benchmark on some days, but no valid data was available to confirm this..

Trends

Seasonal

National benchmarks were exceeded on 11 days in summer, compared with 21 days in spring. Warkworth usually records the highest number of exceedances in the Upper Hunter, accounting for seven exceedance days in spring. Warkworth had no valid PM10 data in summer, therefore, the total number of exceedances may be underestimated.

Summer recorded 42 Fair AQC days, similar to 41 in spring. Bushfire smoke, local dust and photochemical smog contributed to Fair conditions. On 19 of those days, ozone alone resulted in a Fair AQC, likely due to photochemical smog.

Summer 2025-26 recorded 11 exceedance days, the second-highest summer total since 2019/20. Smoke from nearby bushfires likely contributed significantly. The Upper Hunter also recorded 42 Fair AQC days, the highest summer total since the network began. Bushfire smoke and expanded ozone monitoring likely contributed to the result.

12-month review

Rolling 12-month particle averages to February 2026 were generally similar to averages recorded during periods ending February 2025 and 2024. 

PM10 averages were below the annual benchmark at all stations except Warkworth, where the reported average was 28.8 µg/m³. Warkworth was also above the benchmark in the previous two periods. An instrument fault left Warkworth without valid PM10 data during summer 2025/26, limiting interpretation of its latest average. 

PM2.5 averages were below the annual benchmark at all stations. They have been stable in recent years and remain lower than when the network began.

Rainfall across the region was generally average to above average over the 12 months, although the second half of the period was drier than average.