Hunter large population centres
- Upper Hunter – Aberdeen, Singleton and Muswellbrook
- Lower Hunter – Beresfield, Newcastle and Wallsend
- Newcastle Local – Carrington, Mayfield and Stockton
Gaseous pollutants
Ozone (O3), sulfur dioxide (SO2) and nitrogen dioxide (NO2) remained within the relevant national benchmarks in the Upper Hunter, Lower Hunter and Newcastle local networks during 2022. In 2021, there was one day with a 1-hour SO2 level above the standard, recorded at Muswellbrook in the Upper Hunter.
The highest 1-hour SO2 level in the Hunter population centres in 2022 was 10.0 pphm, recorded at Muswellbrook station in the Upper Hunter on 17 March 2022. Measurements of SO2 were only available at Muswellbrook from late February onwards in 2022, due to an instrument fault. This is important to note as based on historical data, SO2 levels at Muswellbrook are usually higher during summer and can exceed the standard levels.
Note that the measured level of SO2 must be at least 0.1 pphm higher than the national standard for it to be considered an exceedance.
PM10 particles
Within the Hunter population centres, PM10 levels generally are highest at Stockton in the Newcastle local region, due to the influence of sea salt under onshore winds (Lower Hunter Particle Characterisation Study). Refer to the Stockton page for more information.
In the Upper Hunter region, PM10 levels generally are highest at stations closest to mining activity.
Annual averages
In 2022, annual average PM10 levels exceeded the 25 µg/m3 benchmark only at Stockton (1 of 9 larger population centres) with a level of 30.3 µg/m3. Excluding Stockton, annual averages ranged from 12.3 µg/m3 at Aberdeen to 19.3 µg/m3 at Carrington.
Daily averages
Daily average PM10 levels exceeded the benchmark on one day in Hunter population centres, excluding Stockton. This occurred on 27 January 2022 at Mayfield in Newcastle, due to an unidentified source. Hourly PM10 levels were elevated morning and afternoon, under moderate easterly winds.
At Stockton, the daily PM10 average was over the benchmark on 37 days, with the predominant cause on each of those days determined to be sea salt under onshore air flows. Refer to the Stockton page for more information.
The maximum daily PM10 average recorded in the Hunter population centres occurred at Stockton on 17 January 2022 with a level of 95.9 µg/m3. Excluding Stockton, the maximum daily PM10 level in the Hunter population centres occurred at Mayfield with a level of 72.0 µg/m3 on 27 January 2022.
PM2.5 particles
Annual averages
Annual average PM2.5 levels in 2022 remained within the 8 µg/m3 benchmark at all 8 stations measuring PM2.5 in the Hunter's large population centres, noting that PM2.5 is not currently recorded at Aberdeen. Annual averages ranged from 5.0 µg/m3 at Beresfield to 7.5 µg/m3 at Stockton.
Daily averages
There were no daily average PM2.5 levels recorded over the benchmark at any of the Hunter population centres in 2022, which is similar to 2021.
The maximum daily average PM2.5 level was 23.7 µg/m3, recorded at Stockton on 18 January 2022, and was predominantly caused by sea salt under onshore air flows. The second highest day occurred at Carrington on 21 February 2022 with a level of 19.9 µg/m3, and was likely due to smoke from bushfire activity at Port Stephens.