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.