Air Quality Categories

Air quality was generally very good across the Newcastle region in autumn 2025, remaining below national benchmarks on 87 days (95% of the season).

The Newcastle region recorded the following air quality categories (AQCs) for autumn 2025:

• Below benchmarks:
  • Good AQC: 64 days (70% of autumn days)
  • Fair AQC: 23 days (25%)
• Above benchmarks:
  • Poor AQC: 4 days (4%)
  • Very Poor AQC: 1 day (1%)

Exceedances

National benchmarks were exceeded on 5 days during autumn, all due to PM10 particles. A dust storm originating in South Australia and Victoria on 26 May passed over eastern New South Wales on 27 May. All 6 Newcastle region stations were among the 60% of stations across the State that exceeded the PM10 daily benchmark on 27 May.

The 4 other PM10 exceedance days all occurred at Stockton and were likely caused by sea salt brought onshore by east to southeasterly winds.

There were no exceedances of national benchmarks during autumn 2025 for PM2.5 particles, nitrogen dioxide, sulfur dioxide, ozone or of the ammonia assessment goal.

Trends

Season

Regional air quality improved slightly compared to summer 2024-25, when there were 9 days over the benchmarks. In both seasons, most exceedances occurred at Stockton, from sea salt. A seasonal shift in wind direction in autumn away from onshore winds resulted in fewer PM10 exceedances at Stockton from sea salt.

Regionally, there was a higher proportion of days in the Good AQC during autumn compared to summer, including at Stockton.

There were fewer exceedances this autumn in the Newcastle region (5 days) compared to 10 days in autumn 2024 and 12 days in autumn 2023, the vast majority of which occurred at Stockton due to sea salt.

The Newcastle region experienced very-much-above-average rainfall during autumn, which may have also played a role in minimising exceedances (Poor or higher AQC days) and Fair AQC, while contributing to a higher proportion of Good AQC days.

12-month review

Air quality in the Newcastle region in the 12 months to the end of autumn was predominantly below the relevant benchmarks. 12-month rolling averages (1 June 2024 to 31 May 2025) for PM10 and PM2.5 were below the annual national benchmarks for all sites, except for PM10 at Stockton (31.0 µg/m3). These PM10 and PM2.5 levels are among the lowest observed in the last 10 years. This is likely due to the very-much-above-average rainfall recorded in the 12 months to the end of May 2025, much of which occurred during autumn 2025. In the case of Stockton, it recorded its lowest 12-month rolling average for the June to May period for both PM10 and PM2.5 since the network began during the 1 June 2024 to 31 May 2025 period.