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Environment and Heritage

NSW annual air quality statement 2022: gases

Levels of ozone and carbon monoxide remained within the national standards in 2022. Sulfur dioxide and nitrogen dioxide levels were within the national standard on all but one day each in 2022.

 

Carbon monoxide (CO)

The national standard for carbon monoxide (CO) is:

  • eight-hour average – 9 parts per million (9 ppm).

Eight-hour carbon monoxide averages

There were no days with levels over the 8-hour CO standard in 2022, the same as 2021. The maximum 8-hour CO average was 1.1 ppm, recorded at Liverpool in South West Sydney on 16 June 2022.

The special projects Bradfield Highway roadside monitoring station (north of the Sydney Harbour Bridge, adjacent to one of the state's busiest roads) recorded a maximum 8-hour CO average of 0.9 ppm on 16 February 2022.

Nitrogen dioxide (NO2)

Th national standards for nitrogen dioxide (NO2) are:

  • one-hour average – 8 parts per hundred million (8 pphm)
  • annual average – 1.5 parts per hundred million (1.5 pphm).

One-hour nitrogen dioxide averages

There was one day with NO2 levels above the national standard in 2022, compared with no days in 2021. This occurred at Coffs Harbour on the Mid North Coast on 17 March 2022. In total, 4 hours were measured above the standard on this day, with a maximum 1-hour average of 24.5 pphm. These elevated levels were likely caused by sources within the immediate vicinity of the station and would not likely reflect the ambient air quality levels experienced in the region.

Excluding 17 March 2022 at Coffs Harbour, the next highest 1-hour NO2 average in 2022 at non-roadside monitoring stations was 4.2 pphm. This occurred at Prospect in Central West Sydney and Campbelltown in South West Sydney.

The special projects Bradfield Highway roadside monitoring station (north of the Sydney Harbour Bridge, adjacent to one of the state's busiest roads) recorded a maximum 1-hour NO2 average of 6.6 pphm on 10 February 2022.

Annual nitrogen dioxide averages

Annual average NO2 levels remained within the national standard in 2022 at all non-roadside stations. The maximum annual NO2 average was 1.1 pphm at non-roadside monitoring stations, recorded at Cook and Phillip in East Sydney.

The NO2 annual average recorded at Bradfield Highway roadside monitoring station was 1.8 pphm, which is over the 1.5 pphm annual benchmark.

Ozone (O3)

The national standard for Ozone (O3) is:

  • eight-hour average – 6.5 parts per hundred million (6.5 pphm).

Eight-hour ozone averages

There were no days over the 8-hour ozone standard in 2022, compared with 5 days in 2021.

The maximum 8-hour ozone average in 2022 was 6.5 pphm, recorded at Albion Park South in the Illawarra on 10 February 2022.

Note that the measured level of ozone must be at least 0.1 pphm higher than the national standard for it to be considered an exceedance.

The special projects Bradfield Highway roadside monitoring station (north of the Sydney Harbour Bridge, adjacent to one of the state's busiest roads) recorded a maximum 8-hour ozone average of 3.7 pphm on 24 December 2022.

Sulfur dioxide (SO2)

The national standards for sulfur dioxide are:

  • 1-hour average – 10 parts per hundred million (10 pphm)
  • daily average – 2 parts per hundred million (2 pphm).

One-hour sulfur dioxide averages

There was one day with SO2 levels above the national standard in 2022, the same as 2021. This occurred at Morisset in the Lake Macquarie region on 19 October 2022, with a maximum 1-hour average SO2 level of 18.3 pphm, followed by a 1-hour average of 14.0 pphm. This was likely due to industrial emissions from nearby power stations, occurring under light north-west to north-east winds.

The next highest 1-hour average SO2 level in 2022 was 10.0 pphm, recorded at Muswellbrook in the Upper Hunter on 17 March 2022. However, 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 historical data indicates the levels of SO2 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.

The special projects Bradfield Highway roadside monitoring station (north of the Sydney Harbour Bridge, adjacent to one of the state's busiest roads) recorded a maximum 1-hour SO2 average of 1.9 pphm on 11 November 2022.

Daily sulfur dioxide averages

There were no days over the daily SO2 standard in 2022.

The maximum daily SO2 average was 1.8 pphm, recorded at Morisset in Lake Macquarie on 19 October 2022. The next highest was 1.6 pphm at Muswellbrook in the Upper Hunter on 17 March 2022.

The special projects Bradfield Highway roadside monitoring station (north of the Sydney Harbour Bridge, adjacent to one of the state's busiest roads) recorded a maximum daily SO2 average of 0.4 pphm on 11 November 2022.