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.

Air Quality Categories

Air quality was exceptionally good across the Newcastle region during winter 2025, remaining below national benchmarks on 90 days (98% of the season).

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

• Below benchmarks:
  • Good AQC: 77 days (84% of winter days)
  • Fair AQC: 13 days (14%)
• Above benchmarks:
  • Poor AQC: 2 days (2%)

Exceedances

National benchmarks were exceeded on 2 days during winter, both due to PM10 particles. These exceedances occurred at Stockton on 5 July 2025 and 8 August 2025. They were likely caused by sea salt brought onshore by east to southeasterly winds.

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

Trends

Season

Regional air quality was generally similar in winter to autumn 2025, when there were 5 days over the benchmarks. In both seasons, all exceedances occurred at Stockton, from sea salt. A seasonal shift in wind direction in winter towards predominately north westerly winds resulted in fewer PM10 exceedances at Stockton from sea salt compared to autumn.

Regionally, there was a higher proportion of days in the Good AQC during winter compared to autumn, including at Stockton due to less sea salt, owing to seasonal shifts in wind direction.

There were more exceedances this winter in the Newcastle region (2 days) compared to no days in winter 2024 and the same as winter 2023 (2 days). Exceedances in winter 2023 occurred at Stockton and were caused by a combination of sea salt and industrial activity.

The Newcastle region experienced above average to very-much-above-average rainfall during winter. This may have limited exceedances (Poor or worse AQC days) and Fair AQC, resulting in more days spent in the Good AQC.

12-month review

Air quality in the Newcastle region in the 12 months to the end of winter has predominantly been below the relevant benchmarks, except for PM10 and PM2.5 at Stockton. The 12-month rolling averages for the 1 September 2024 to 31 August 2025 period for PM10 and PM2.5 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 August 2025, much of which occurred during autumn and winter 2025.

Air Quality Categories

Air quality was generally good across the Newcastle region during spring 2025, remaining below national benchmarks on 85 days (94% of the season).

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

• Below benchmarks:
  • Good AQC: 45 days (50.5% of spring days)
  • Fair AQC: 39 days (43%)
• Above benchmarks:
  • Poor AQC: 5 days (5.5%)
  • Very Poor AQC: 1 day (1%)

Exceedances

PM10 and PM2.5 levels exceeded national benchmarks on 6 days across all six monitoring stations during spring 2025. Bushfire smoke is attributed to 3 days above national benchmarks in November (dust also contributed on 14 November). Local dust was attributed to exceedances on 2 days during spring, while sea salt likely caused 2 exceedances at Stockton.

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

Trends

Season

Spring recorded a higher number of benchmark exceedances (6 days) compared to winter 2025 (2 days). However, there was a significant increase in the proportion of Fair AQC days in spring (39 days) compared to winter (13 days). The Newcastle region recorded 6 days above national benchmarks compared to 12 days in spring 2024 and 24 days in spring 2023. This is likely due to Stockton recording the fewest hours of onshore winds in spring 2025 than any other spring over the past 11 years. This likely led to fewer PM10 exceedances at Stockton from sea salt during the season. Spring 2025 had a similar proportion of Fair AQC days to spring 2024 and 2023.

The 6 exceedance days occurred in the second half of spring, due in part to bushfire smoke. It is possible the below average rainfall and highest on record maximum temperatures the Newcastle region experienced during spring took time to impact air quality in the region. This might be due to the average temperatures and very much above average rainfall recorded during winter.

12-month review

With the exception of PM10 at Stockton (30.0 µg/m3), all other 12-month rolling PM10 and PM2.5 averages remained below the national benchmark in the 12 months to the end of November 2025. Levels were similar to the previous 12-month period ending November 2024. In general, both PM10 and PM2.5 12-month rolling averages are stable at levels below those recorded before the 2019-2020 bushfire season.