upper hunter air quality monitoring network

Upper Hunter Air Quality Monitoring Network

Interim performance report: December 2010–August 2011

© Copyright State of NSW and the NSW Office of Environment and Heritage.

With the exception of photographs, the NSW Office of Environment and Heritage and State of NSW are pleased to allow this material to be reproduced in whole or in part for educational and non-commercial use, provided the meaning is unchanged and its source, publisher and authorship are acknowledged. Specific permission is required for the reproduction of photographs. The NSW Office of Environment and Heritage (OEH) has compiled this publication in good faith, exercising all due care and attention. No representation is made about the accuracy, completeness or suitability of the information in this publication for any particular purpose. OEH shall not be liable for any damage which may occur to any person or organisation taking action or not on the basis of this publication. Readers should seek appropriate advice when applying the information to their specific needs.

Acknowledgements

The following open-source statistical software was used in the data analysis for this report::

R: R Development Core Team (2011). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, www.R-project.org/.

Openair: David Carslaw and Karl Ropkins (2011). Openair: Open-source tools for the analysis of air pollution data. R package version 0.5-11.

Front cover photo: Maison Dieu site; Upper Hunter air quality monitoring network. Photo: OEH.

Published by: NSW Office of Environment and Heritage 59–61 Goulburn Street PO Box A290 Sydney South 1232 Report pollution and environmental incidents Environment Line: 131 555 (NSW only) or [email protected] See also www.environment.nsw.gov.au Phone: (02) 9995 5000 (switchboard) Phone: 131 555 (environment information and publications requests) Phone: 1300 361 967 (national parks, climate change and energy efficiency information and publications requests) Fax: (02) 9995 5999 TTY users: phone 133 677 then ask for 131 555 Speak and Listen users: phone 1300 555 727 then ask for 131 555 Email: [email protected] Website: www.environment.nsw.gov.au ISBN 978 1 74293 530 0 OEH 2012/0164 February 2012

Upper Hunter Air Quality Monitoring Network: Interim performance report: December 2010–August 2011 3

Contents

About this report 4

Executive summary 5

About the Upper Hunter Air Quality Monitoring Network 7

What is the network? 7

Who is responsible for the network? 7

What will the network tell us? 7

What are the national benchmarks for air quality? 9

How do these benchmarks apply to the Upper Hunter region? 10

Where are the monitoring stations located? 10

When will the network be complete? 12

How is the network performing? 12

Air quality results 16

PM10 in larger population centres 16

PM10 in smaller communities 17

PM10 at diagnostic sites 18

PM2.5 monitoring data 23

What do the air quality results tell us? 27

How are the monitoring results reported? 28

Appendix 1: How are particles measured in the UHAQMN? 30

Appendix 2: Daily average PM10 data 32

Appendix 3: Daily average PM2.5 data 35

Glossary 38

4 Office of Environment and Heritage

About this report

This the first report on the Upper Hunter Air Quality Monitoring Network (UHAQMN). It covers the period from December 2010 to August 2011.

As at August 2011, the network is at the half-way stage in its construction and is on track to have all monitoring stations operating by the end of December 2011.

The current amount of data collected is not sufficient to provide robust conclusions on regional air quality in the Upper Hunter. This will require all of the monitoring stations to have been online and providing information for at least 12 months to cover any seasonal trends and for at least three years to cover the variation in weather conditions.

In the interim, as well as providing background information about the network, this reports covers:

the progress of the network construction

how well the network is performing, and

questions raised by analysing the air quality data gathered to date.


Executive summary

The Upper Hunter Air Quality Monitoring Network (UHAQMN) has been established to provide the community with information about levels of dust particles in the air, to identify emission sources, and, on a long-term basis, to inform regulatory programs that may be required to reduce these emissions. The network will provide the community with hourly updates on current air quality in near real-time via the Office of Environment and Heritage (OEH) website.

Eventually, 14 monitoring stations will be established to serve a particular purpose:

background information: Merriwa and Singleton South

larger population centres: Singleton Central, Muswellbrook Central and Aberdeen

smaller communities: Bulga, Camberwell, Warkworth, Maison Dieu, Jerrys Plains and Wybong, and

diagnostic information: Mount Thorley, Singleton North West and Muswellbrook North West.

When fully built, the UHAQMN will continuously measure particles (as PM10), wind speed and wind direction at all 14 monitoring sites, finer particles (as PM2.5) at Singleton, Muswellbrook and Camberwell and sulfur dioxide and oxides of nitrogen at Singleton and Muswellbrook.

This interim report is intended to provide an update mid-way through the establishment of the network. As at August 2011, the network is half completed and is on track to have all monitoring stations operating by the end of December 2011. After initial problems with instrumentation, the current network is regularly providing valid and accurate particle, wind speed and direction data in excess of 95% of the time.

Daily average PM10 and PM2.5 levels are measured against benchmark values of 50 µg/m3 and 25 µg/m3 respectively. During the reporting period these levels were mostly less than the relevant benchmark except for those days outlined in Table 1.

Even though the network is only partially complete, it is already providing valuable information on air quality in the Upper Hunter region. PM10 at the two major population centres of Singleton and Muswellbrook and PM2.5 at Singleton appear to be on track to meet the relevant benchmarks.

Potential issues with PM2.5 in Muswellbrook have been identified; these are being further investigated by OEH and NSW Health. Individual case studies at Muswellbrook (for PM2.5) and at Singleton North West (for PM10) provide examples of the type of analysis that can be undertaken once the network is complete. Although monitoring sites at smaller population centres had only been operating for short periods when this report was prepared, future analysis of this information will provide valuable information to these communities and guide any necessary response. Diagnostic sites yield valuable information about the sources and pathways of particulate matter.


Table 1: Network days above the PM10 and PM2.5 benchmarks

Parameter Station Daily average (µg/m3)

Date Comments

Singleton Central

54.8 01/02/2011 Hot, windy conditions

51 05/04/2011 Possibly due to gravel being placed around the monitoring site

50.2 11/05/2011 Moderate winds from NW direction

Maison Dieu

61.4 05/07/2011 Hourly PM10 spike associated with high winds (> 50 km/h) from NW direction

56.8 01/08/2011 Levels over the benchmark at Singleton North West are associated with calm conditions where wind was from the NW direction

53.3 02/08/2011

69 03/08/2011

51.5 04/08/2011

Singleton North West

51 05/08/2011

Camberwell 51.1 03/08/2011 Elevated hourly values associated with winds from NNW direction

PM10

Mount Thorley 57.1 03/08/2011

26 25/06/2011 Elevated hourly values associated with winds mainly from SE, S and SW directions

25.8 26/06/2011

28.3 27/8/2011

PM2.5 Muswellbrook Central

27.7 28/8/2011


About the Upper Hunter Air Quality Monitoring Network

What is the network?

The Upper Hunter Air Quality Monitoring Network (UHAQMN) is a high-quality, regional air quality monitoring network that continuously measures dust particles in the air. The network provides the community with hourly updates on current air quality in near real-time via the Office of Environment and Heritage (OEH) website.

When fully built, the network will consist of 14 monitoring stations linked to a central database. From here the data will be uploaded hourly to the OEH website.

The network will continuously measure:

particles (as PM10), wind speed and wind direction at all 14 monitoring sites

finer particles (as PM2.5) at Singleton, Muswellbrook and Camberwell, and

sulfur dioxide and oxides of nitrogen at Singleton and Muswellbrook.

Who is responsible for the network?

The UHAQMN is a partnership between the NSW Government and the Upper Hunter coal and power industries. The sites are being constructed, operated and maintained by OEH staff using funds contributed by industry under Deeds of Agreement.

The Upper Hunter Air Quality Monitoring Network Advisory Committee was established to advise OEH on matters specifically related to the design and operation of the network. The Advisory Committee has 13 members representing the community, the coal and power generation industries, local government and state government agencies.

The Advisory Committee met five times during the period covered by this report, endorsing the locations of proposed monitoring stations, providing valuable feedback on the design of a new webpage, and monitoring progress on the construction of the network.

What will the network tell us?

The network will provide government, industry and the community with credible, reliable and up-to-date information about air quality and trends in air quality within the Upper Hunter Valley.

This information can be used to:


assess changes in air quality

help identify the major sources of the monitored pollutants, and

inform regulatory programs in response to long-term trends.

The monitoring network is based on a design developed by Holmes Air Sciences in 2008. The 14 monitoring stations are located to serve a particular purpose:

background: the stations near Merriwa and Singleton South are at both ends of the valley and provide background data, measuring the quality of air entering and leaving the Hunter Valley under predominant winds (south-easterlies and north-westerlies)

larger population centres: the stations near the larger population centres will monitor the air quality in these centres

smaller communities: the stations located in smaller communities will monitor the air quality at those locations, and

diagnostic: the intention is that these sites will provide data that will help to diagnose the likely sources and movement of particles across the region as a whole, but they don’t provide information about air quality at population centres.

Table 2: Station types

Description Station type

Merriwa and Singleton South Background

Singleton Central, Muswellbrook Central and Aberdeen

Larger population centre

Bulga, Camberwell, Warkworth, Maison Dieu, Jerrys Plains and Wybong

Smaller population centre

Mount Thorley, Singleton North West and Muswellbrook North West

Diagnostic

All the stations together make up the network. Information about Upper Hunter regional air quality and trends in air quality will be gained by analysing data from the network as a whole.

Information from the network will help OEH to design and guide specific investigations into the questions raised by the data, such as questions about the distribution of particles and the components making up the fine particle fraction of the particle mix. This information will assist OEH in developing further monitoring and compliance programs to improve Upper Hunter air quality – in addition to the existing government initiatives which include regulatory actions, Regional Land Use Plans and the ‘Dust Stop’ program seeking best management practice from mines.


What are the national benchmarks for air quality?

The Australian benchmark for air quality is the Ambient Air Quality National Environment Protection Measure (the Air NEPM). The Air NEPM defines the national standards and goals for the various aspects of air quality, including the concentration of dust particles.

Table 3: NEPM standards and goals for dust particles

Pollutant How often is the average measured?

Benchmark (concentration)

Goal: how often can the concentration exceed this benchmark?

Particles as PM10 Daily: 1 calendar day (24 hours)

50 µg/m3 Maximum 5 days a year

Particles as PM2.5 Daily: 1 calendar day (24 hours)

Annual: 1 calendar year (12 months)

25 µg/m3

8 µg/m3

Goal is to gather sufficient information to allow a standard to be set when the Air NEPM is reviewed. This benchmark is an Australia-wide advisory reporting standard until a standard is made.

For example, this means that the daily average concentration of PM10 particles should not exceed 50 µg/m3 more than five days a year. As the network has not been operating for a full calendar year, benchmarking against the annual standard of 8 µg/m3 for PM2.5 is not possible for this report.

Measuring dust particles

Particle size (µm)

Particles are measured as:

PM10 (particles 10 micrometres in diameter and smaller), and

PM2.5 (finer particles 2.5 micrometres in diameter and smaller).

1 micrometre (µm) = one millionth of a metre.

Particle concentration (µg/m3)

The concentration of dust particles in the air is measured as the mass of the particle in micrograms (µg) per volume of air in cubic metres (m3).

1 microgram (µg) = one millionth of a gram.


How do these benchmarks apply to the Upper Hunter region?

Air quality data can be compared against the Air NEPM goal of PM10 not reaching higher than 50 µg/m3 (averaged over 24 hours) for more than five days a year in population centres. Although there is no national goal for PM2.5, data from the network can be compared to the advisory reporting standard of 25 µg/m3 (averaged over 24 hours).

The air quality benchmarks don’t apply directly to the diagnostic monitoring sites (i.e. the monitoring stations that are located solely to enable diagnosis of dust sources). For example, the Singleton North West monitoring station measures the quality of air moving from the mining areas to the north-west towards Singleton. Data from these diagnostic sites will be compared against the air quality benchmarks on the OEH website and for interpretative purposes using various statistical analysis techniques to help identify likely sources of dust particles. Examples of this kind of analysis are contained in the ‘Air quality results’ section of this report.

Where are the monitoring stations located?

The locations and operational status of the UHAQMN sites are shown in Figure 1.

The Muswellbrook and Singleton sites were chosen before the Advisory Committee was formed – this was done to ensure that 2 stations in the major population centres of Singleton and Muswellbrook were operational as soon as practicable.

By the end of June 2011, the Advisory Committee had considered and then endorsed all of the 12 remaining station locations.

The full list of 14 stations is as follows:

Aberdeen Muswellbrook Central

Bulga Muswellbrook North West

Camberwell Singleton Central

Jerrys Plains Singleton North West (Rixs Creek)

Maison Dieu Singleton South

Merriwa Warkworth

Mt Thorley Wybong

The only change made by the Advisory Committee to the originally proposed network was the replacement of Muswellbrook West with a station at Wybong.

Upper Hunter Air Quality Monitoring Network: Interim performance report: December 2010 – August 2011 11

Figure 1: Monitoring station locations


When will the network be complete?

As of 31 August 2011, seven of the 14 stations were operational and providing hourly updates to the OEH website.

In addition, a new Upper Hunter webpage providing information about particle concentrations and wind speed and direction was commissioned.

The key milestones for constructing the UHAQMN are set out in Table 4. Work progress is on track to complete the network within the planned timeframe.

Table 4: Milestones for completing the monitoring network

Milestone Description Completion/ Target date

1 Singleton Central & Muswellbrook Central online Stage 1 OEH webpages online

31 Dec 2010

2 Maison Dieu online (total 3 sites online) 31 Mar 2011

3 Bulga, Camberwell, Mt Thorley & Singleton North West online (total 7 sites online)

30 Aug 2011

4 Stage 2 OEH webpage online 30 Aug 2011

5 Aberdeen, Muswellbrook North West, Singleton South & Warkworth online (total 11 sites online)

30 Nov 2011

6 Merriwa, Jerrys Plains & Wybong online (total 14 sites online)

31 Dec 2011

7 Sulfur dioxide and oxides of nitrogen measured at Singleton Central and Muswellbrook Central

30 Nov 2011

How is the network performing?

The network is regularly providing valid and accurate particle, wind speed and direction data in excess of 95% of the time.

As with any network of complex scientific instruments, regular maintenance and calibration is essential. Maintenance and calibration schedules for the UHAQMN comply with the relevant Australian Standards for servicing the equipment and ensure that the network provides accurate and timely data to the community. Maintenance and calibration tasks require about 5% of the network’s running time. Therefore an operational aim of the network is to achieve at least 95% online time for all parameters measured.


As Table 5 shows, total online performance (for hourly data) at all sites to the end of August 2011 achieved the 95% benchmark.

Table 5: % online performance of the UHAQMN to 31 Aug 2011

Site Start date PM10 PM2.5 Wind direction

Wind speed

Singleton 9/12/2010

Muswellbrook 9/12/2010

Maison Dieu 1/4/2011

Camberwell 25/7/2011

Singleton NW 25/7/2011

Mt Thorley 25/7/2011

Bulga 12/8/2011

Key:

> 95 % online

90 – 95% online

85 – 90% online

< 75% online

Atypical results during conditioning periods

Performance levels below 95% can be expected when monitoring stations are first established and the instruments are still undergoing conditioning and settling in. Events that led to monthly performance levels below the desired 95% benchmark are outlined in Table 6.

Table 6: Network data loss during conditioning periods

Site Parameter Date Comment

20/12/2010 – 22/12/2010

Negative data invalidated – issue resolved by instrument maintenance.

24/3/2011 – 25/3/2011

Negative data problem resolved through instrument maintenance.

Muswellbrook Central

PM2.5

28/3/2011 Sampler tape contaminated by foreign matter after instrument maintenance on 25/3/2011. This led to false elevated readings.


Site Parameter Date Comment

29/3/2011 – 30/3/2011

Instrument offline for further maintenance.

26/5/2011 – 27/5/2011

Valid daily averaged data unable to be calculated due to power failure.

PM10 12/1/2011 – 13/1/2011

Instrument alarm due to vacuum pump failure.

Wind speed/ wind direction

16/3/2011 Ongoing intermittent sensor problems resolved.

Singleton Central

PM10 22/3/2011 – 23/3/2011

Valid daily averaged data unable to be calculated due to instrument maintenance.

Maison Dieu PM10 29/5/2011 Grossly negative data invalidated (filter element problem resolved).

After the conditioning periods for instruments at the Singleton Central, Muswellbrook Central and Maison Dieu sites, online performance is now regularly above 95%.

Gaps in hourly data

Under national air quality guidelines and protocols, an ‘average’ is deemed valid only when at least 75% of data during the averaging period is valid. (Therefore, a valid rolling 24-hour average or daily 24-hour average is only calculated when at least 18 valid hourly averages are available). As a consequence, where hourly data values are marked invalid, there may be periods when daily averages are not reported on the OEH website.

Gaps in data can be due to:

scheduled maintenance and calibration where the following are carried out on a regular basis:

quarterly – clean sample head and inlet and replace filters; leak check (1–2 hours)

6-monthly – flow audit (1–2 hours)

annual – software (1–2 hours) and hardware calibration (1–2 hours); zero stability check (at least 8 hours); site audit (1–2 hours)

equipment failure at site or communications failure between instrument and data logger (variable): data can be lost for either of these reasons – there will be gaps in the database and on the web

power outages at site (variable): data is lost as equipment is powered off during the outage


telecommunication problems (variable): data will not be loaded to the website during this period; however, the data is not lost but downloaded to the database and uploaded to the web once communication is re-established

website maintenance (variable): data is not lost because it is stored locally until the website is up and running again.

However, in spite of this potential for data loss, the network is maintaining the 95% benchmark for online performance.


Air quality results

PM10 in larger population centres

Figure 2: Daily average PM10 levels (9 December 2010 to 31 August 2011)

Daily average PM10 levels at Muswellbrook Central were less than the 50 µg/m3 benchmark throughout the reporting period.

Daily average PM10 levels at Singleton Central were less than the 50 µg/m3 benchmark throughout the reporting period except for one day: 1 February 2011. Conditions on this day were extremely hot (41°C maximum temperature), dry (relative humidity of 21% at 3pm) and moderately windy (24 km/h at 3pm). Despite these conditions, the measured level (55 µg/m3) only marginally exceeded the benchmark.

Table 7 shows days during the reporting period where the daily average PM10 exceeded the Air NEPM PM10 benchmark.


Table 7: Days above the PM10 benchmark, larger population centres

Parameter Station Concentration (µg/m3)

Date Comments

PM10 Singleton Central

54.8 01/02/2011 Hot, windy conditions.

The Air NEPM PM10 goal is for no more than five days over the benchmark in a 12-month period. As the stations have been operating only since December 2010, it is not yet possible to compare the data with this goal.

PM10 in smaller communities

The Maison Dieu monitor has been operating since April 2011. Since then, daily average PM10 levels at Maison Dieu have been less than the 50 µg/m3 benchmark except for three days:

51.0 µg/m3 was the daily average on 5 April 2011, marginally exceeding the benchmark. It is possible that this was due to gravel being placed around the monitoring site as part of the final work in its construction.

50.2 µg/m3 was the daily average on 11 May 2011 during a period of moderate north-westerly winds.

61.4 µg/m3 was the daily average on 5 July 2011 during a period of gale-force north- westerly winds

The Camberwell monitor has been operating since mid-July 2011. Since then, daily average PM10 levels at Camberwell have been less than the 50 µg/m3 benchmark except for one day:

51.1 µg/m3 was the daily average on 3 August 2011 during a period of calm to moderate wind from the north-north-west.

The Bulga monitor operated for just nineteen days during the period covered by this report. Daily average PM10 levels at Bulga were less than the 50 µg/m3 benchmark at all times.

Table 8 shows days during the reporting period where the daily average PM10 exceeded the PM10 benchmark.


Table 8: Days above the PM10 benchmark, smaller communities


Date Comments

51.0 05/04/2011 Possibly due to gravel being placed around the monitoring site.

50.2 11/05/2011 Moderate winds from north-west direction.

Maison Dieu

61.4 05/07/2011 Hourly PM10 spike associated with high winds (> 50km/h) from north-west direction.

PM10

Camberwell 51.1 03/08/2011 Elevated hourly values associated with winds from north-north-west.

PM10 at diagnostic sites

These sites operate to provide information on trends and likely sources of dust. There is only a short period of data available for the two of these sites in operation during the period covered by this report (Mount Thorley and Singleton North West).

Table 9: Days above the PM10 benchmark, diagnostic sites


Date Comments

56.8 01/08/2011

53.3 02/08/2011

69.0 03/08/2011

51.5 04/08/2011

Singleton North West

51.0 05/08/2011

These higher-than-benchmark levels at Singleton North West were associated with calm conditions where wind direction was from the north-west.

PM10

Mount Thorley 57.1 03/08/2011

As these sites have been operating for a limited period, long-term trend analysis is not possible, but the analysis for Singleton North West (in the case study below) is provided to give an example of how the data might be used once the network is fully established.


CASE STUDY

PM10 at Singleton North West

On 1 August 2011, PM10 levels at Singleton rose to 41.7µg/m3 and remained at above average levels until 5 August. While PM10 levels in Singleton remained below the 50 µg/m3 benchmark throughout this period, this provides an opportunity to demonstrate how the network will provide information on potential sources if significant dust events occur in future.

The Singleton North West monitoring station is located between the main coal mining areas to the north-west of Singleton and Singleton itself. This monitor is within the area likely to be directly impacted by mining (known as a ‘zone of effect’), where landholders have rights to compensation under development approval conditions. Therefore it is inappropriate to compare the levels recorded at this site with benchmarks that apply to population centres. Instead, the purpose of this site is to enable analysis of likely dust sources.

Figure 3a: Singleton North West station – hourly PM10 values (1 to 5 August 2011)

Figure 3a shows a plot of hourly PM10 values against the hour of the day (from hour 0 [12am] to hour 23 [11pm]) on the horizontal X-axis. The PM10 values are also colour coded by wind speed categories and then grouped into sectors (N, NE, E, SE, S, SW, and NW) according to direction from which the wind was blowing.


During this five-day period, the Singleton North West monitoring station showed daily average PM10 levels ranging from 51.0 to 69.0 µg/m3 and weather monitoring showed that winds were consistently from the north-west and calm – less than 7 km/h. Hourly PM10 levels above 75 µg/m3 originated almost exclusively from the north-west sector.

By analysing all of the hourly data provided by the Singleton North West monitoring station, we can see that almost all of the high PM10 values were associated with winds from the north-west quadrant (Figure 3b). Figure 3b is a plot of the number of hours during the sampling period categorised by the concentration level of PM10 and wind direction. It shows that all hourly PM10 values > 75 µg/m3 originated from a source to the north-west (i.e. from a direction between 270° and 360°) of the monitoring station.

Figure 3b: Singleton North West station – hourly PM10 values > 75 µg/m3 by wind direction (25 July to 31 August 2011)

NOTE: 75 µg/m3 was chosen as a lower cut-off point to highlight only those hours with relatively elevated

hourly PM10 levels. It is a purely arbitrary choice.

Corroboration that elevated PM10 levels are associated with winds blowing from the north-west is provided by analysing all hourly data collected at Singleton North West since its installation date (25 July 2011). Figures 3c and 3d show diurnal (hour-of-day) and day-of-week profiles of all hourly PM10 values collected over the sampling period.

S

W E

N


The diurnal plot for all hours collected at Singleton North West (Figure 3c) shows the fluctuations of PM10 levels throughout the day (averaged for each hour between hours 0–23) for PM10 hourly values grouped by wind quadrant north-west (pink) against all other quadrants (blue).

Figure 3c: Singleton North West station – hourly PM10 values averaged for each hour of day

Wind direction is shown in two categories: wind from the north-west (NW) quadrant compared with wind from all other quadrants.

For each wind category, the graph shows the PM10 average and 95% confidence intervals. The coloured lines indicate the mean PM10 levels averaged for each hour of the day. The coloured areas for wind directions denote the 95% confidence intervals around the mean PM10 values.

Figure 3d: Singleton North West station – hourly PM10 values averaged for each day of the week

In Figure 3d, all Monday hours are averaged over the sampling period, all Tuesday hours are averaged, and so on, to obtain an average for each day of the week for the two wind direction categories.

This graph highlights that there are significant differences in PM10 levels originating from different points of the compass around the Singleton North West monitoring station.


As in Figure 3a, there appears to be an association of higher PM10 levels with hours overnight from 10pm–9am.

Analysis like this will help OEH focus its regulatory efforts if significant dust problems are identified by the network in the future. In Fig 3d, based on day of the week, PM10 levels from the north-west quadrant (pink) can be seen to be significantly higher than for all other quadrants (blue).

Outcomes – how are effects of PM10 on air quality in the Upper Hunter being improved?

Dust Stop

The Dust Stop program aims to reduce dust emissions by ensuring that the most reasonable and feasible dust control options are implemented by coal mines throughout NSW. Under this program, all coal mines have six months to prepare a report that compares their current operation with international best practice. Mines are also required to report on the practicability of implementing each best practice measure. For any measures that are found to be practicable, each mine is required to provide a timetable for implementation.

The Dust Stop program is being implemented through Pollution Reduction Programs attached to each coal mine licence. During the reporting period, Pollution Reduction Programs were issued to three Upper Hunter mines: Bengalla, Liddell and Mount Arthur. Copies of each coal mine licence are available on the POEO public register (at www.environment.nsw.gov.au/prpoeoapp/).

To search the public register for Upper Hunter coal mine licences, pick ‘coal works’ from the drop-down menu under ‘Fee-based activity’ and ‘Muswellbrook’ or ‘Singleton’ under ‘LGA’.


PM2.5 monitoring data

Figure 4: Daily average PM2.5 levels (9 December 2010 to 31 August 2011)

PM2.5 data is gathered at the Camberwell, Singleton Central and Muswellbrook Central monitoring stations.

Camberwell

Daily average PM2.5 levels at Camberwell were less than the 25 µg/m3 benchmark throughout the reporting period.

Singleton Central

Daily average PM2.5 levels at Singleton Central were less than the 25 µg/m3 benchmark throughout the reporting period.

Muswellbrook Central

Daily average PM2.5 levels at Muswellbrook Central were less than the 25 µg/m3 benchmark throughout the reporting period except for four days.

The PM2.5 daily average benchmark was topped marginally at Muswellbrook in June and August 2011 coinciding with overnight, cold and calm conditions (Table 10).


Table 10: Days above the PM2.5 benchmark (9 December 2010 – 31 August 2011)


Date Comments

26.0 25/06/2011

25.8 26/06/2011

28.3 27/8/2011

PM2.5 Muswellbrook Central

27.7 28/8/2011

Elevated hourly values were associated with winds mainly from the south-east, south and south-west.

CASE STUDY

PM2.5 at Muswellbrook Central

To investigate the higher daily averages during the cooler months, statistical analysis was conducted on the hourly average levels.

Figures 5a and 5b display hourly PM2.5 values grouped by hour of day, wind speed, wind direction and by month. In Figure 5a, all of the elevated hourly PM2.5 values were associated with wind speeds less than 5 km/h and with hours overnight during mornings and evenings.

Figure 5a: Muswellbrook Central station – daily variation in hourly PM2.5 values in relation to wind speed (9 December 2010 – 31 August 2011)


The monthly plot in Figure 5b also shows that elevated PM2.5 values only occurred during the winter months starting from May. At the same time, the pollution roses in Figures 5c and 5d indicate that the predominant wind direction for hourly PM2.5 levels > 35 µg/m3 is from the south-east.

Cool temperatures overnight, the calm conditions on 25 and 26 June and the topography of Muswellbrook are factors similar to those in other rural areas in NSW which experience elevated fine particle levels during cooler months. The monitoring site and most of the surrounding residential area sit in the Hunter River valley. During winter months, cooler heavier air tends to flow from elevated areas to pool in areas of low elevation. Under these conditions, particles can be trapped in the valley until the sun warms the air, which rises. Normal convection during the day then dilutes the particles with fresh air and PM2.5 levels drop. This is exactly the scenario that is demonstrated in Figure 5b, of PM2.5 concentration plotted against hour of the day averaged over the month.

Figure 5b: Muswellbrook Central station – daily variation in all hourly PM2.5

values in relation to wind direction and (i) time of day and (ii) month of the year

NOTE: The coloured lines indicate the mean PM2.5 levels averaged for each hour of the day. The coloured

areas for wind directions denote the 95% confidence intervals around the mean PM2.5 values.


Figure 5c: Muswellbrook Central station pollution rose – hourly PM2.5 values > 35 µg/m3 for all months (9 December 2010 – 31 August 2011)

Figure 5d: Muswellbrook Central station pollution roses – hourly PM2.5 values > 35 µg/m3 by calendar month (9 December 2010 – 31 August 2011)

NOTE: In Figures 5c and 5d, 35 µg/m3 was chosen as a lower cut-off point to highlight only those hours

with relatively elevated hourly PM2.5 levels. It is a purely arbitrary choice.

The time of day and seasonal aspects of these results, together with Muswellbrook’s topography and wintertime conditions, suggest that the source of the particles is likely

S

W E

N


to be smoke-related; combustion processes are a major source of fine particles as PM2.5.

Outcomes – How is air quality in the Upper Hunter being improved?

Further particle characterisation studies

To better understand the source of PM2.5 particles in the Muswellbrook area, NSW Health and OEH plan to conduct research studies to answer questions relating to the contribution of woodsmoke to fine particle concentrations and the fine particle fraction composition in the Upper Hunter. The Australian Nuclear Science and Technology Organisation (ANSTO) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) have been engaged to undertake a 12-month program of sampling and analysis to determine what the PM2.5 particles consist of.

Preventing woodsmoke

In late August 2011, OEH provided a one-day training workshop in the Upper Hunter for local council staff responsible for managing woodsmoke. The workshop was attended by council officers from Hunter, Singleton and Muswellbrook. The workshop explored the significance of woodsmoke in the region and strategies for reducing it.

In general, attendees believed attention should mainly focus on other emission sources. However, based on past council case studies and OEH’s presentation on educational, policy and regulatory measures for woodsmoke, there was broad agreement that there are practical and worthwhile measures councils can take to improve woodsmoke management.

What do the air quality results tell us?

Even though the network has been operating for less than 12 months, it is already providing valuable information on air quality in the Upper Hunter region. PM10 at the two major population centres of Singleton and Muswellbrook and PM2.5 at Singleton appear to be on track to meet relevant benchmarks.

The network has identified potential issues with PM2.5 in Muswellbrook which are being further investigated by OEH and NSW Health.

Other monitoring sites at smaller population centres had only been operating for short periods when this report was prepared. Future analysis of this information will provide valuable information to these communities and guide any necessary response.

Diagnostic sites yield valuable information about the sources and pathways of particulate matter.


How are the monitoring results reported?

Upper Hunter air quality monitoring network webpages

The map webpage (www.environment.nsw.gov.au/aqms/uhunteraqmap.htm) for the Upper Hunter went live on 30 August 2011. The number of page views for the period 26 August to 22 September 2011 is shown in Figure 6 below. The number of visits increased after 30 August, another peak occurred on 9 September and page views have remained steady since.

Figure 6: Page views for the UHAQMN map webpage

The website, which is updated hourly, provides facilities for viewing Upper Hunter air quality data. Anyone visiting the website can view the hourly PM10, PM2.5, wind direction and wind speed data, create their own graphs of the hourly data, download historical data and compare Upper Hunter values to those for the rest of NSW.

SMS and email alerts

As with OEH’s main Air Quality Monitoring Network, readings from the UHAQMN trigger automatic SMS and email alerts to inform the community when air quality is ‘poor’. This is designed to allow those members of the community who may be susceptible to air pollution (e.g. asthmatics, people with heart disease) to subscribe to these automatic alerts.

OEH has promoted this service via its website, through community meetings and communication with stakeholders and through the media. You can subscribe to the alerts at www.environment.nsw.gov.au/aqms/subscribe.htm

Subscribers to all operating sites (as at 22 September 2011) in the UHAQMN are shown in Table 11.


Table 11: Numbers of subscribers to the alerts

Subscription service Public subscribers OEH subscribers

Email High AQI Bulga 5 4

Email High AQI Camberwell 5 4

Email High AQI Maison Dieu 5 4

Email High AQI Mt Thorley 6 3

Email High AQI Muswellbrook Central 56 7

Email High AQI SingletonCentral 52 7

Email High AQI Singleton North West 4 4

SMS High AQI Bulga 3 4

SMS High AQI Camberwell 3 4

SMS High AQI Maison Dieu 2 4

SMS High AQI Mt Thorley 3 3

SMS High AQI Muswellbrook Central 21 8

SMS High AQI Singleton Central 21 8

SMS High AQI Singleton North West 2 4

Key:

Online 9/12/2010

Online 6/5/2011

Online 30/8/2011)

Note: High AQI refers to an index value 100 or greater, meaning that the concentration levels for PM10 or

PM2.5 rolling 24-hour averages were above benchmarks of 50 µg/m3 and 25 µg/m3 respectively.


Appendix 1: How are particles measured in the UHAQMN?

Two methods can be used to collect air quality data:

Reference methods: involve batch collection of fine particles on filter paper over 24 hours. Samples are collected and then transported to special laboratory facilities for weighing and reporting of results. This process can take 2–3 weeks.

Continuous methodologies: because of the time lag associated with reference methods, OEH chose recognised techniques to provide the continuous data required for the web-based community reporting and alert systems it operates.

Two different types of continuous monitoring instruments are used throughout the UHAQMN, one measuring PM10 and one PM2.5. Both are recognised as equivalent methods to the relevant reference method by the US Environmental Protection Agency and are designated as Federal Equivalent Methods (FEM).

Measurement of PM10

The Tapered Element Oscillating Microbalance (TEOM) instrument was chosen for the continuous measurement of PM10. A TEOM PM10 instrument will be located in each of the 14 monitoring stations making up the UHAQMN.

These instruments, fitted with a size-selective PM10 inlet, draw a constant volume of ambient air through a filter which is mounted on a vibrating hollow glass tube (the tapered element). Particles are collected on the filter, which then increases in weight. This additional weight changes how often the tapered element vibrates (or oscillates) from one side to the other. The mass of the particles is determined by the change in oscillation frequency. The mass is divided by the volume of air sampled by the instrument over the same time period to produce the mass/unit volume (micrograms/cubic metre: µg/m3).

Because the particles can include water (via rain or humidity) as part of their mass, the sensor unit is heated to 50°C to remove water from the particles collected on the filter. The TEOMs operate on a continuous basis and the data averaged over one hour is assembled and transmitted to the OEH data centre for further processing and posting on the OEH website (hourly updates).


Measurement of PM2.5

The Beta Attenuation Monitor (BAM) was chosen for the continuous measurement of PM2.5. Three BAMs will be located in the UHAQMN at Singleton Central, Muswellbrook Central and Camberwell.

These instruments are fitted with size-selective inlets and very sharp cut cyclones (VSCC) to collect the PM2.5 sample stream which is then heated (to reduce the effects of humidity) and passed through a filter tape. The amount of heating is determined by the humidity levels of the incoming sample stream.

The particles are deposited onto the glass fibre tape and then the particle mass is irradiated with beta radiation. Fine particle mass is proportional to the attenuation of this radiation through a known sample area to continuously collect and detect the measured mass.

The simultaneous mass measurements of particles on the filter tape and sample volume measurement through a calibrated orifice provide a continuous concentration measurement in micrograms/cubic metre. The hourly averaged PM2.5 data is collected and posted on the OEH website (hourly updates).

TEOM instrument – used for PM10 BAM instrument– used for PM2.5

Photos by OEH


Appendix 2: Daily average PM10 data

The following calendar plots show daily average PM10 levels categorised against a benchmark of 50 µg/m3. Days where levels are higher than the benchmark are coloured orange, maroon or red. The categories are those used in the OEH Regional Air Quality Index (RAQI) web pages; values shown in the colour key are in µg/m3.


Appendix 3: Daily average PM2.5 data

The following calendar plots show daily average PM2.5 levels categorised against a benchmark of 25 µg/m3. Days where levels are higher than the benchmark are coloured orange, maroon or red. The categories are those used in the OEH Regional Air Quality Index (RAQI) web pages; values shown in the colour key are in µg/m3.


Glossary

Confidence limit – After the average of a sample of observations has been calculated (e.g. calculating the average PM10 value for each day of the week over a year), in analysing these data it is useful to give some indication of how close this sample average is to the population average. One way to do this is to determine a confidence interval, whose upper and lower values are defined as confidence limits. Usually, 95% confidence limits are used. Providing 95% confidence limits means that if repeated random samples are taken from a population and the average of each sample calculated, the confidence interval for 95% of samples taken would include the population average. The size of the 95% confidence interval gets smaller with larger sample sizes and also when sample values are closer together. Usually, if confidence intervals for samples do not overlap, the averages for each sample are seen to be different from one another (for example, in the graph below, the averages for blue samples above the orange line are different to those for the blue samples below the orange line).

Day-of-week plot – is a way of displaying patterns of pollutant values averaged for each day of the week over a prolonged sampling period e.g. for a month, quarter, season or year.

Diurnal plot – is a way of displaying patterns of pollutant levels throughout hours of the day averaged over a period of time. For example, over a month all pollutant levels with


a time stamp of 1am are averaged, all levels with a timestamp of 2am are averaged, and so on for all hours of the day up to midnight.

Pollution rose – is another way of presenting pollutant data in relation to the wind direction recorded for the same time at a monitoring site. In the image below, wind direction data are counted for each of the pollutant categories. The colour categories represent hourly PM10 levels; the angle of the coloured wedges represents the direction from which the wind is blowing associated with each of these pollutant categories. The concentric circles show number of hours for each category (the scale for these counts is displayed at a 45° angle in the NE wind direction sector of the plot). In the image below, it can be seen that all hourly pollutant values above 75 µg/m3 originated from the NW sector.

Quadrant – refers to directions on a compass divided into four broad regions, namely:

the NE quadrant refers to directions between 0° (North) and 90° (East)

the SE quadrant refers to directions between 90° (East) and 180° (South)

the SW quadrant refers to directions between 180° (South) and 270° (West)

the NW quadrant refers to directions between 270° (West) and 360° (North).

See image above under Pollution rose.

S

W E

N

upper hunter air quality monitoring network

Documents