NSW annual air quality statement 2020: focus areas

The Air Quality Statement 2020 has 4 focus areas – Hunter Valley, Stockton, air quality impacts of the COVID-19 pandemic-related social-economic restrictions and major achievements in air quality monitoring, forecasting and research during the year.

Summary

The NSW Government maintains 20 air quality monitoring stations in the Hunter Valley; 3 government-funded stations in the Lower Hunter, 3 industry-funded stations around the port of Newcastle and 14 industry-funded stations in the Upper Hunter.

The government-operated, industry-funded Upper Hunter and Newcastle Local air quality monitoring networks were established in 2011 and 2014, respectively, to monitor local industrial and other pollution sources. Due to the proximity of industrial sources, the national ambient air quality standards do not apply directly to the data collected at these monitoring stations. However, the government recognises the community’s interest in knowing how air pollution levels at these stations compare against the standards. Therefore, this section refers to national standards as national benchmarks when evaluating air quality data throughout the Hunter Valley.

More information on these networks can be found on the government website, including seasonal newsletters.

Large population centres

Hunter large population centres

Gaseous pollutants

Ozone, sulfur dioxide and nitrogen dioxide met the relevant hourly, daily and annual national benchmark in the Upper and Lower Hunter regions, including the Newcastle Local network, during 2020.

In comparison, in 2019, there were 5 days over the ozone benchmark in the Lower Hunter.

PM10 particles

Within the Hunter Valley, PM10 levels generally are highest at Stockton in the Newcastle port area, due to the influence of sea salt under onshore winds (Lower Hunter Particle Characterisation Study). (Refer to the Stockton tab for more information.) In the Upper Hunter region, PM10 levels generally are highest at stations closest to mining activity.

Annual averages

In 2020, annual average PM10 levels exceeded the 25 µg/m3 benchmark only at Stockton (one of 9 stations in larger population centres). Annual averages ranged from 17.7 µg/m3 at Wallsend to 34.5 µg/m3 at Stockton.

Daily averages

Daily average PM10 levels exceeded the benchmark on 17 days at one or more stations in large population centres (excluding Stockton). These occurred on:

  • 1–8, 11–12, 20–21 and 23–24 January
  • 19 February
  • 19 August
  • 29 November 2020

At Stockton, the daily PM10 average was over the benchmark on 55 days, predominantly affected by sea salt under onshore air flows, bushfire smoke and long-range dust transport. Refer to the Stockton tab for more information.

The maximum daily PM10 averages recorded in the Hunter population centres occurred on 11 January 2020, due to a widespread dust storm through the Upper Hunter. The maximum PM10 levels in the Upper Hunter and Newcastle regions on this day were 267.7 µg/m3 at Aberdeen and 65.1 µg/m3 at Stockton, respectively.

PM2.5 particles

Annual averages

Annual average PM2.5 levels exceeded the 8 µg/m3 benchmark at Stockton, Muswellbrook and Singleton, 3 of 7 stations measuring PM2.5 in the Hunter’s large population centres (PM2.5 annual averages were not available at Newcastle in 2020 due to less than 75% of data available for the year). Annual averages ranged from 7.3 µg/m3 at Wallsend to 9.3 µg/m3 at Stockton and Muswellbrook.

Daily averages

Daily average PM2.5 levels exceeded the benchmark on 13 days at one or more large population centres. These occurred on:

  • 1–5, 8–9 and 11–12 January and 24 January
  • 6–8 June

During January, the region was affected by smoke from extensive bushfires and dust storms. In June, the Hunter was affected by smoke, most likely from domestic wood heating during cold and calm overnight conditions. The Upper Hunter Fine Particle Characterisation Study found that woodsmoke was a major contributor to PM2.5 levels at Muswellbrook and Singleton in winter 2012.

The maximum daily average PM2.5 level occurred on 8 January 2020 at Newcastle in the Lower Hunter, due to bushfire smoke and long-range transport of windblown dust. On this day, PM2.5 levels in the Lower Hunter ranged from 49.7 to 78.5 µg/m3.

In the Upper Hunter, the maximum daily average PM2.5 level of 49.1 µg/m3 occurred at Muswellbrook on 5 January 2020, due to bushfire smoke and windblown dust transported into the region. On this day Camberwell and Singleton recorded PM2.5 daily averages of 36.6 and 37.2 µg/m3, respectively.

Upper Hunter air quality monitoring network

The Upper Hunter air quality monitoring network comprises 14 stations – 3 stations in larger population centres, 6 stations in smaller communities, 3 diagnostic stations close to mining operations and 2 background stations at the north-west and south-east extents of the region.

Annual averages

All monitoring stations in the Upper Hunter recorded annual average PM10 levels below the 25 µg/m3 benchmark. PM10 annual averages in the Upper Hunter ranged from 17.8 µg/m3 at Aberdeen to 24.3 µg/m3 at Camberwell. 

The highest annual average PM10 levels occurred at stations closer to mines, Camberwell (24.3 µg/m3) and Warkworth (23.7 µg/m3), followed by the Muswellbrook population centre (22.5 µg/m3).

Two of 3 stations monitoring PM2.5 in the Upper Hunter, Muswellbrook and Singleton, recorded annual average PM2.5 levels exceeding the 8 µg/m3 benchmark, as noted above. PM2.5 annual averages ranged from 7.5 µg/m3 at Camberwell to 9.3 µg/m3 at Muswellbrook.

Daily averages

The Upper Hunter recorded 35 days with daily average PM10 levels over the benchmark at one or more stations, compared to 120 days in 2019.

Camberwell recorded the highest number of days over the PM10 daily benchmark in the region, with a total of 18 days, compared to 87 days at Camberwell in 2019.

All stations in the Upper Hunter, except Camberwell, recorded their highest daily average PM10 levels in January, during intense drought conditions, extensive bushfires and frequent widespread dust storms across New South Wales.

The highest daily average PM10 level of 620.7 µg/m3 occurred at the Merriwa background station on 11 January 2020, during a widespread dust storm under westerly to north-westerly winds. This was the highest daily PM10 average recorded throughout the State during 2020.

Chart summarising PM10 levels in the Upper Hunter 2020

# Days exceeding standard the benchmark have not been divided into exceptional and non-exceptional events, as the NEPM goals do not apply to these sites.

Summary

The Stockton air quality monitoring station is part of the industry-funded Newcastle Local Air Quality Monitoring Network, focused around the Port of Newcastle. The station is approximately 300 metres from the ocean and 20 metres from Hunter River. Due to its proximity to the coast, high PM10 particle levels recorded at Stockton most often occur under onshore north-easterly winds. The Lower Hunter Particle Characterisation Study found that the largest contribution to PM10 at Stockton was sea salt.

Due to the proximity of industrial sources, the national ambient air quality standards do not apply directly to the data collected at these monitoring stations. However, the government recognises the community’s interest in knowing how air pollution levels at these stations compare against the standards. Therefore, this section refers to national standards as national benchmarks when evaluating air quality data throughout Stockton.

For PM10, in 2020:

  • The daily PM10 particle levels at Stockton were over the national benchmark of 50 µg/m3 on 55 days (compared with 102 days in 2019). Stockton typically records the most days exceeding the PM10 benchmark across the NSW air quality monitoring network, due to the station’s exposure to sea salt in onshore winds.
  • The PM10 annual average reached 34.5 µg/m3 (compared to 43.6 µg/m3 in 2019), the highest in New South Wales and the only annual record exceeding the national benchmark of 25 µg/m3 in 2020.
  • Most of the days exceeding the PM10 standard at Stockton (44 days, 80% of the annual total) occurred in the warmer months of January to March and October to December, when onshore winds typically prevail and sea salt contribution increases. In January, when PM10 levels were over the daily benchmark on 16 days (29% of the annual total), the region also was greatly affected by long-range dust transport and extensive bushfire smoke during the severe drought and bushfire emergency period.
  • Elevated hourly PM10 levels (>75 µg/m3, an indicative level as there is no standard for hourly PM10) occurred 6.5% of the time over the year, as shown in the PM10 pollution rose below. These elevated hourly PM10 levels occurred under:
    • onshore north-easterly to south-easterly winds for 65% of hours with elevated PM10 (4.2% total time for the year), indicating the potential contribution of sea salt
    • north-west winds for 10% of hours with elevated PM10 (0.6% total time for the year).
  • During 2020, the NSW Government began reporting against an hourly PM10 threshold of 100 µg/m3. At Stockton, hourly PM10 levels exceeding 100 µg/m3 occurred 2.4% of the time over the year. These levels occurred under:
    • onshore north-easterly to south-easterly winds for 65% of hours when PM10 was over 100 µg/m3 (1.6% total time for the year)
    • north-west winds for 9% of hours when PM10 was over 100 µg/m3 (0.2% total time for the year).

For PM2.5 in 2020:

  • The daily PM2.5 particle levels at Stockton were over the benchmark of 25 µg/m3 on 4 days (compared with 27 days in 2019).
  • The PM2.5 annual average exceeded the benchmark of 8 µg/m3, reaching 9.3 µg/m3 (compared to 13.0 µg/m3 in 2019).
  • All PM2.5 events at Stockton occurred in January, during the bushfire emergency period.
  • Elevated hourly PM2.5 levels (>40 µg/m3, an indicative level as there is no standard for hourly PM2.5) occurred 0.8% of the time over the year, as shown in the PM2.5 pollution rose below. These levels occurred under north-west winds for 16% of hours with elevated PM2.5 (0.1% of time for the year).
  • During 2020, the NSW Government began reporting against an hourly PM2.5 threshold of 50 µg/m3. At Stockton, hourly PM2.5 levels exceeding 50 µg/m3 occurred 0.4% of the time over the year. These levels did not occur under north-west winds.

Local industrial sources also contribute to particle levels at Stockton, under north-west winds. The Lower Hunter Particle Characterisation Study found that Stockton PM2.5 levels in winter, under north-west winds, were influenced mainly by direct emissions of ammonium nitrate particles from industry, located approximately 1 kilometre to the north-west, on Kooragang Island.

Hourly ammonia (NH3) levels were below the assessment goal of 46 pphm at Stockton throughout 2020. The maximum hourly NH3 level was 30.3 pphm, recorded on 16 June 2020. The annual average ammonia level was 1.4 pphm.

For more information on seasonal air quality at Stockton, refer to the Newcastle seasonal newsletters.

Summary

  • One of the major effects of the COVID-19 pandemic related lockdowns and other socio-economic restrictions issued by the State and Commonwealth public health authorities, was a reduction in vehicle traffic. Vehicle exhaust is a key contributor to urban air pollution in New South Wales.
  • Two examples of how the COVID-19 related restrictions impacted air quality in New South Wales are provided. These focus on nitrogen oxides (NOx), here defined as the total of nitrogen dioxide (NO2) and nitric oxide (NO), which are one family of key air pollutants species generated by fossil fuel combustion. Key findings are:
    • reductions in NOx concentrations were observed at a roadside air quality monitoring station, consistent with the reduction in vehicle numbers during 2020
    • further reductions in NOx concentrations were observed at several stations in the network during various stages of COVID-19 related restrictions on social activity in the year.
    • levels of NO2, one component in NOx, also decreased at some stations in the network during the May–June period, when compared with previous years.
  • Air quality impacts which result from changes in emissions can be difficult to quantify with direct measurements alone, as air quality can be affected by many factors including meteorology (e.g. wind, temperature and rainfall) and other pollution sources (such as bushfires) and atmospheric chemistry. Further research is underway to holistically investigate the overall air quality impacts (e.g. carbon monoxide, NOx, particle and ozone levels) due to pandemic-related restrictions.

Background

Restrictions and changes in community behaviour associated with COVID-19 pandemic occurred from March 2020. The pandemic has resulted in a change in how the community works and undertakes other activities, which in turn can affect air quality.

Reductions in vehicle traffic were anticipated to have a large impact on NOx emissions and associated nitrogen dioxide (NO2) levels in the air. The reductions will also lower other pollutant emissions, such as carbon monoxide, particulate matter and volatile organic compounds.

In this brief analysis, we focused on the changes in NOx and NO2 concentrations associated with the COVID-19 related restrictions on social activities and the subsequent reduction in vehicle traffic volume. NOx concentrations in 2020 were compared against previous years at: (a) a roadside air quality monitoring station; and (b) ambient air quality monitoring stations in the Greater Metropolitan Region.

Bradfield Highway

A roadside monitoring station was commissioned in October 2018 to measure pollutant concentrations adjacent to Bradfield Highway in Milsons Point. This road is the northern entrance to the Sydney Harbour Bridge and is one of the busiest roads in New South Wales.

Data on vehicle numbers were not available for the section of the highway next to the monitoring station. However, traffic data for the Cahill Expressway, one of the connecting roads on the southern side of the Harbour Bridge, were available. The data showed a significant reduction in vehicle numbers during the COVID-19 lockdowns in 2020, compared with the same periods in 2019.

  • NOx concentrations on weekdays over 4 time periods in 2020 were compared with 2019:
    • Period 1: Pre-COVID-19 (1 February to 10 March)
    • Period 2: COVID-19 lockdown (21 March to 30 April). This involved restriction of non-essential travel.
    • Period 3: Gradual easing phase (1 May to 30 June). Gradual easing of travel restrictions from mid-May.
    • Period 4: Further easing phase (1 July to 31 August). Further easing of travel restrictions from early July.
  • NOx concentrations during the pre-COVID-19 period were similar between 2019 and 2020, across the entire day. The profile showing peaks in the morning and evening is consistent with higher vehicle numbers during peak hours.
  • A reduction in NOx concentrations was observed during each of the 3 lockdown periods in 2020, when compared to 2019. This was consistent with the reduction in the number of vehicles shown below. The differences between 2019 and 2020 were greater during Period 2 and Period 3, which were the lockdown and gradual easing periods. As travel restrictions further eased and traffic numbers increased in Period 4, the difference between NOx concentrations narrowed.
Weekday vehicle numbers on Cahill Expressway, one of the major roads which feeds to the southern access of the Sydney Harbour Bridge, by hour of the day during the 4 periods of analysis. Data available from the NSW Roads and Maritime Service Traffic Volume Viewer (https://www.rms.nsw.gov.au/about/corporate-publications/statistics/traffic-volumes/aadt-map/)
Graph showing the comparison of nitrogen oxide concentrations at roadside Bradfield Highway monitoring station on weekdays in 2019 and 2020, by hour of the day, during (a) Period 1 (1-February to 10-March); (b) Period 2 (21-March to 30-April); (c) Period 3 (1-May to 30-June); and (d) Period 4 (1-July to 31-August)

Greater Metropolitan Region

  • A comparison was made between weekday average concentrations of NOx and NO2 at selected locations in the Greater Metropolitan Region (GMR), comprising the Sydney, Central Coast, Lower Hunter and Illawarra regions.
  • NOx concentrations typically are higher in cooler months in urban areas, due to cooler temperatures and less turbulent air mixing of NOx emissions within the lower atmosphere. Additionally, long-term NOx concentrations are falling at some locations due to improvements in emissions technologies.

Sydney

Average concentrations of nitrogen oxides (NOx) and nitrogen dioxide (NO2) are compared between 2014 and 2020 at Randwick (Sydney East), Chullora (Sydney Central East) and Richmond (Sydney West) monitoring stations in Sydney. Four time periods in each year are compared, which correspond to pre-COVID, first lockdown, gradual easing and further easing phases in 2020.

Overall, there were distinguishable reductions in total weekday average NOx and NO2 concentrations in Period 3 (May-June) and Period 4 (July-August), compared to previous years. NOx and NO2 levels in Period 2 (the strictest lockdown in March and April) were generally lower compared to 2019, but not very different from some previous years (e.g. 2018) at Randwick and Chullora.

It is acknowledged that variations in NOx and NO2 levels may also be associated with the effect of the interannual variability in meteorology, difference in spatial positioning of monitoring stations relative to emission sources, and atmospheric chemistry. Research is under way to further examine the potential effects of different factors on air quality for the period of interest.

Lower Hunter, Central Coast and Illawarra

Average concentrations of nitrogen oxides (NOx) and nitrogen dioxide (NO2) are compared between 2014 and 2020 at Newcastle (Lower Hunter), Wyong (Central Coast) and Wollongong (Illawarra) monitoring stations. Four time periods in each year are compared, which correspond to pre-COVID, first lockdown, gradual easing and further easing phases in 2020.

All three monitoring stations in the Lower Hunter, Central Coast and Illawarra regions recorded significant reductions in NOx and NO2 concentrations during Period 3 (May – June) in 2020, when compared to previous years.

For Periods 2 and 4, the comparison results appear complex and the reason for this is currently under investigation.

We continue to improve our air quality monitoring, forecasting and research capabilities in meeting the data and information need by the people of New South Wales.

Expansion of air quality monitoring in 2020

In 2020, the NSW Government expanded the standard air quality monitoring network from 51 to 55 stations and the rural network was expanded from 35 to 39 stations.

  • Coffs Harbour and Port Macquarie on the Mid-north Coast, previously deployed during the 2019-2020 bushfire emergency, were converted to long-term monitoring stations in April 2020.
  • Rural stations at Grafton and Lismore in the Northern Rivers, Merimbula on the South Coast, and Cooma in the Snowy Mountains, previously deployed during the 2019-2020 bushfire emergency, have been maintained as long-term stations of the rural network, in April 2020.
  • Penrith, in the Sydney North-west region, was commissioned in July 2020.
  • Morisset, in the Lake Macquarie region, was commissioned in November 2020.
  • Lidcombe, in the Sydney East region, was commissioned in March 2020, to replace the nearby Chullora station that will be decommissioned in 2021.
  • The Merriwa background air quality monitoring station in the Upper Hunter region was upgraded in July 2020 to monitor particles as PM2.5, visibility, ozone, nitrogen oxides, carbon monoxide and sulfur dioxide.
  • 12 stations in the rural network were upgraded to measure particles indicatively as PM2.5 and PM10. All 33 rural stations in New South Wales, and 3 of 6 located in other states, now measure PM2.5 and PM10 separately.

Better public information

Reporting of hourly average particle levels

We upgraded our website in response to community requests for improved reporting of near-real time changes in air quality, publishing hourly-averaged particle measurements and enhanced health guidance and advice in February 2020.

Reporting of air quality categories

We introduced air quality categories (AQC) to replace air quality indices (AQI), applying a nationally consistent approach for reporting hourly PM2.5 data and associated health advice in November 2020.

Expansion of data delivery services

We launched additional online data service tools that support customised delivery of current and historical air quality and meteorological data to response agencies, businesses and the public.

Review of Air Quality Monitoring Plan for New South Wales

The revised NSW Air Quality Monitoring Plan explains how the NSW government intends to monitor ambient air quality across metropolitan and regional areas, during the five-year period 2020–2025. The Plan meets the requirement of National Environment Protection (Ambient Air Quality) Measure (AAQ NEPM), Part 4 Section 10, that each jurisdiction must have a plan setting how it proposes to monitor air quality to meet the purposes of the AAQ NEPM. The purpose of air quality monitoring is to build the scientific evidence base for air quality management that reduces pollution and protects communities. The Plan for 2020–2025 focuses on monitoring in five regions with the highest population, Greater Sydney, the Lower Hunter, the Central Coast, the Illawarra region and the Albury-Wodonga region.

For more information, please see the NSW Air Quality Monitoring Plan 2020-25.

Research projects

Blue Mountains and Lithgow Air Watch

At the request of the Blue Mountains and Lithgow community groups, the EPA commissioned a 12-month air quality monitoring project in partnership with the Department of Planning, Industry and Environment’s Atmospheric Science Branch.

The Blue Mountains and Lithgow Air Watch project found that between the 1 June 2019 and 31 May 2020, the air quality in Katoomba (where the compliance station was located) was generally very good. Air quality complied with the national air quality standards, outside of the period of the exceptional bushfires of spring–summer 2019–2020.

The Sydney Air Quality Study

The first-phase report (PDF 14.2MB) of the Sydney Air Quality Study (covering 2017–2019) was released in November 2020. This report discusses how air quality has changed in Greater Sydney over the past two decades. It also includes new insights into the contribution of major sources to air pollution and population exposure in the region.

The next phase of the study will present new findings on the health cost of air pollution. The health burden analysis based on results published in the first report will be finalised in collaboration with NSW Health and the NSW Environment Protection Authority in 2021.

Enhanced modelling and forecasting capability

The Enhancing Air Quality Forecasting program is progressively improving the accuracy of air quality forecasting in New South Wales. A wide variety of new tools had been developed, tailored, run and validated for predicting air quality in NSW. Major improvements were made in smoke emissions modelling and forecasting during the NSW bushfires in 2019–20 to more accurately predict the smoke and associated health impacts on regional air quality from the extreme scale of the wildfires.

To further enhance the accuracy of air quality forecasting, dynamic modelling of pollutant emissions from human sources, such as residential wood heating, power stations and motor vehicles, has been under development within the Modular Emissions Modelling System (MEMS) project. An advanced wind-blown dust emissions scheme was also being investigated through research collaborations with third-party science providers to better capture the regional air quality conditions during dust storm events.

Regional summer ozone monitoring campaign

New national standards for gaseous pollutants are expected to be introduced by the National Environment Protection Council in 2021. One of the proposed changes is the introduction of a rolling 8-hour standard for ozone, of 6.5 parts per hundred million (pphm), to replace the 1-hour and 4-hour standards. Ozone is measured as a standard parameter in the Greater Metropolitan Region, given it is the major pollutant produced in urban photochemical smog.

However, during the January 2019 heatwave, a concentration just under the standard was measured at Gunnedah, a regional centre in northern New South Wales. As such, a scoping study is being undertaken during the 2020-21 summer to measure ozone levels at five major regional centres in New South Wales. The selected scoping locations are Tamworth, Bathurst, Orange, Albury and Wagga Wagga North. These will supplement measurements made routinely in the Greater Metropolitan Region, and in regional New South Wales at Gunnedah, Goulburn, Port Macquarie and Coffs Harbour.

Community engagement

Air Quality Monitoring must serve community needs. The NSW Government listens and learns from communities, pursuing the best outcomes and creating opportunities that benefit all. Monitoring must always be done for the sake of people’s wellbeing and the prosperity of New South Wales. The NSW EPA leads engagement activities to identify and respond to community needs. The EPA produces a range of draft policies, agreements and reports that call for community involvement, engagement and consultation.

NSW Government Air Program scientists participate in community engagement activities and panels administered by the NSW EPA. Examples include the Lower Hunter Dust Deposition Study, the Namoi Region Air Quality Advisory Committee, the Newcastle Community Consultative Committee on the Environment, and the Upper Hunter Air Quality Advisory Committee.

Other activities include the Rural Air Quality Monitoring Network, which is supported by 39 citizen scientists who help to maintain each station and respond to feedback gathered from the channels listed above.

We value your feedback

We encourage you to provide feedback about the NSW Government’s Air Program.

There are several continuous feedback channels for the public to discuss air quality monitoring and reporting. These include: