Air Quality Monitoring for Particles in Collie

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Air Quality Monitoring for Particulate Matter in Collie, 2004-2007

Technical Report

December 2008

ER NA U STRA

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Air Quality Monitoring for Particles in Collie

2004 – 2007

Final Technical Report

December 2008

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Table of Contents

Definitions and abbreviations ... 5

SUMMARY ... 6

1.0 INTRODUCTION ... 8

1.1 Sources of particles in Collie... 9

1.1.1 Industrial Processes ... 9

1.1.2 Fuel reduction burns ... 9

1.1.3 Domestic sources ... 9

1.1.4 Future sources of particles in Collie... 11

1.2 Health impacts of particles ... 11

2.0 AUSTRALIAN AIR QUALITY STANDARDS AND SCREENING PROCEDURES FOR PARTICLES... 12

3.0 SAMPLING LOCATION AND MONITORING METHOD ... 13

4.0 RESULTS AND DISCUSSION ... 13

4.1 Comparison with Air NEPM standards... 13

4.1.1 PM10 concentration... 13

4.1.2 PM2.5 concentration... 15

4.2 Temporal Variation... 15

4.2.1 PM₁₀ and PM_2.5 concentration at Roche Park... 15

4.2.2 Seasonal and daily variation... 17

4.2.3 Diurnal variation of particle concentrations in winter and summer ... 19

4.3 Comparison with other monitoring stations ... 20

4.3.1 Comparison with Air NEPM standards ... 21

4.3.2 Mass ratio ... 23

4.4 Back trajectories... 23

5.0 CONCLUSIONS ... 24

References ... 26

Websites ... 27

Appendix 1 – Box-whisker plot and monthly summaries of ambient particle concentrations at Roche Park, Collie monitoring station ... 28

2004 PM10... 29

2004 PM_2.5... 30

2005 PM₁₀... 31

2005 PM2.5... 32

2006 PM₁₀... 33

2006 PM_2.5... 34

2007 PM₁₀... 35

2007 PM2.5... 36

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Appendix 2 Back-trajectories for exceedences of the NEPM PM₁₀ standard and the NEPM

PM2.5 advisory standard. ... 37

PM₁₀ and PM_2.5exceedences on 28 April 2004 ... 38

PM₁₀ and PM_2.5 exceedences on 5 May 2004 ... 39

PM₁₀ and PM_2.5exceedences on 17 December 2005... 40

PM10 and PM2.5 exceedences on 9 May 2006 ... 41

PM10 and PM2.5 exceedences on 10 and 11 May 2006 ... 42

PM₁₀ and PM_2.5 exceedences on 12, 13 and 14 May 2006 ... 43

PM₁₀ and PM_2.5 exceedences on 17 and 18 June 2006 ... 44

PM₁₀ and PM_2.5 exceedences on 30 August 2006... 45

PM10 and PM2.5 exceedences on 11 May 2007 ... 46

PM₁₀ and PM_2.5 exceedences on 25 October 2007 ... 47

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List of Figures

Figure 1 Collie region showing the Collie metropolitan area, Roche Park monitoring site and

NPI reporting facilities... 10

Figure 2 Relative contribution of major sources to PM₁₀in Collie during 2006/ 2007 (Data source: http://www.npi.gov.au). ... 11

Figure 3 PM₁₀ daily concentration at Roche Park ... 14

Figure 4 Daily averaged percentiles for PM₁₀, during 2004 - 2007 ... 16

Figure 5 Daily averaged percentiles for PM_2.5, during 2004 – 2007 ... 17

Figure 6 Day:night particle ratios during each season ... 18

Figure 7 Seasonal wind roses for Roche Park monitoring site (2004-2007) ... 19

Figure 8 Diurnal variation of PM₁₀ and PM_2.5 for winter and summer (2004-2007) ... 20

Figure 9 Daily averaged particles as PM₁₀ in Collie, Bunbury and Duncraig ... 22

Figure 10 Daily averaged particles as PM_2.5 in Collie, Bunbury and Duncraig... 23

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List of Tables

Table 1 Air NEPM standards for particles ... 12

Table 2 Particles, as PM₁₀, 24-hour average concentration and compliance... 14

Table 3 Particles, as PM_2.5, 24-hour average concentration and compliance ... 15

Table 4 Summary of PM10 concentration at Roche Park, (µg/m³) ... 15

Table 5 Summary of PM_2.5 concentration at Roche Park, (µg/m³) ... 16

Table 6 Seasonal PM₁₀concentrations (in ug/m³) ... 17

Table 7 Seasonal PM2.5 concentrations (in ug/m³) ... 18

Table 8 Peak daily averaged PM₁₀ concentration (µg/m³) and number of exceeedences for 2004-2007 ... 21

Table 9 Peak daily averaged PM_2.5 concentration (µg/m³) and number of exceeedences for 2004-2007 ... 21

Table 10 Annual averaged PM_2.5 concentrations (µg/m³) for 2004-2007 ... 22

Table 11 Ratio of PM_2.5to PM₁₀ in Collie, Duncraig and Bunbury for 2004-2007... 23

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Definitions and abbreviations

Air NEPM National Environmental (Ambient Air Quality) Protection Measure

Ambient air the external air environment, does not include the air environment inside buildings or structures

Microgram One millionth (1/1,000,000) of a gram (ug)

Micrometre One millionth (1/1,000,000) of a metre (um) or one thousandth (1/1,000) of a millimetre

NEPC National Environment Protection Council NEPM National Environment Protection Measure NPI National Pollutant Inventory

Percentile Value of a variable below which a certain percent of observations fall. For example, the 90^th percentile is a value above which 10% or (10/100) and below which 90% (or 90/100) of all observations fall

PM10 Particles with an equivalent aerodynamic diameter of 10 microns or less

PM2.5 Particles with an equivalent aerodynamic diameter of 2.5 microns or less

TEOM Tapered Element Oscillating Microbalance WHO World Health Organisation

µg/m³ Micrograms per cubic metre

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SUMMARY

The town of Collie has a population of 9000 people and is located in the south-west of Western Australia. Major industries in the region are mining and electricity production.

Particle matter is the sum of all solid and liquid particles suspended in air.

Based on size, particles are often divided into two main groups, namely, PM10

and PM2.5. PM10 is particle matter with an aerodynamic diameter of up to 10 µm. PM2.5 is particle matter with an aerodynamic diameter of up to 2.5 µm and is commonly referred to as the fine particle fraction.

This report provides an assessment of particle monitoring in Collie for the period 2004-2007, and examines the need for future monitoring in the area.

Data were compared to the National Environment Protection (Air Quality) Measure (Air Quality NEPM) and other international health guidelines (i.e.

WHO), and concentrations measured at other West Australian sites. Temporal patterns in the PM10 and PM2.5 data were established by examining annual, seasonal, daily and hourly variations. An overview of the final findings is provided below:

• During the study period the daily average concentration of particles (PM10) exceeded the standard set by the Air NEPM on an average of four days a year. In 2006, the daily average exceeded the Air NEPM standard on nine days and so failed to meet the goal set by Air NEPM in one of the study years.

• The daily averaged PM2.5 concentration exceeded the Air NEPM advisory standard of 25 µg/m³ 10 times in 2004, 3 times in 2005, 13 times in 2006 and 9 times in 2007. Similarly annual average concentration of PM2.5 also exceeded the 8 ug/m³ advisory standard in each year of the study.

• The maximum monthly average concentration for both PM10 and PM2.5

occurs in May.

• The highest concentrations of PM10 and PM2.5 generally occur in autumn as does the highest number of exceedences.

• The periods of high PM10 and PM2.5, when the Air NEPM is exceeded, is almost always due to emissions from fuel reduction burning aimed at the protection of community values from the impact of severe bushfires, domestic wood heating and other fires.

• The duration of exceedences from prescribed burning is usually quite short compared to those produced by other sources.

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• The night time averages for both PM10 and PM2.5 are the highest during autumn and winter months and also significantly higher than the day time values during these months.

• When compared to the other sites around Western Australia (i.e.

Bunbury and Duncraig) Collie had the highest number of exceedences for both PM10 and PM2.5 for the period investigated by this report.

Based on this assessment of ambient PM10 and PM2.5 data, it is recommended that measures are implemented to reduce community exposure to particles. It would be appropriate to continue to monitor particle concentrations to confirm longer term trends. Any plans for future industry also warrant that monitoring should continue for particles in Collie.

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1.0 INTRODUCTION

The term particle pollution or particle matter (PM) includes both solid particles and liquid droplets found in the air.These solid and liquid particles come in a wide range of sizes. The sizes of particles are measured in micrometres (µm) which is 1/1,000,000 of a metre. There are two types of air-borne particles generally measured in the air, these being PM2.5 and PM10. PM2.5 is particle matter with an aerodynamic diameter of up to 2.5 µm and is sometimes referred to as the fine particle fraction. PM10 is particle matter with an aerodynamic diameter of up to 10 µm which by definition also includes fine particles.

This report provides an assessment of available data¹ (January, 2004 to December, 2007) for ambient particle concentrations in Collie and examines the need for future monitoring in the Collie area.

The main objectives of the study were to:

• Compare particle concentrations in Collie with the ambient air quality National Environment Protection Measure (NEPM) standards and goals;

• Examine day-night and seasonal variations in PM10 and PM2.5

concentrations;

• Determine if and when periods of high concentrations occur;

• Assess the need to monitor PM10 and PM2.5 in Collie in the future.

This study is a component of a systematic review of the air quality within Western Australia. The study will aim to provide a strategic basis for government and industry decision making on key issues such as land use planning and infrastructure development. This will ensure the ongoing maintenance of acceptable air quality in the area whilst accommodating for the impact of future development.

The town of Collie is located at 33° 21’ 35”S, 116° 09’ 09”E in the south-west of Western Australia and is approximately 170 km from Perth. Collie is situated at the junction of the Collie and Harris rivers, with a population of approximately 9000 people. The major industries in the Collie area are mining and electricity production.

January and February are typically the hottest months of the year with mean maximum temperatures of 30.5 ôC and 30.1 ôC respectively. The coldest month is July with a mean daily maximum temperature of 15.5 ôC. The average minimum temperatures range from 4.2 ôC in July to 13.2 ôC. The average annual rainfall for Collie is 940 mm. The highest rainfall generally is in

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winter, with June averaging 180.5 mm. The driest period is during summer with approximately 15 mm rainfall per month.

1.1 Sources of particles in Collie

In Collie, there are various sources that contribute to elevated particle concentrations

1.1.1 Industrial Processes

The National Pollutant Inventory (NPI) identified a number of industrial facilities that emit sources of PM10 emissions to the Collie area. The locations of these industrial sources are shown in Figure 1. The relative PM10 source contribution of the various industry sectors within the Collie area as identified by NPI is depicted in Figure 2.

1.1.2 Fuel reduction burns

Throughout the south-west of Western Australia, including around Collie, the Department of Environment and Conservation, industry and private landowners, use fire as an important land management tool. Prescribed burns have been used around Collie for many years for a range of purposes, including to provide strategic protection to community assets (including life and property) and to protect, maintain and enhance biodiversity and ecological processes.

1.1.3 Domestic sources

Wood heaters are another important source of particles in Collie.

DEC undertook a major review of the use of woodheaters in the Collie area in 2006 as part of the Synovate Pty Ltd survey. More than 200 householders were interviewed, providing a high level of confidence in the results.

The survey revealed that wood heaters are the most prevalent form of home heating in Collie, with 93 per cent of the surveyed homes having a wood heater (e.g. potbelly, open-fire place, slow combustion) (Synovate, 2006).

Gas heaters, split system reverse cycle air conditioners, electric heaters and other forms of heating are in the minority as the main source of home heating in Collie.

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Figure 1 Collie region showing the Collie metropolitan area, Roche Park monitoring site and NPI reporting facilities

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Figure 2 Relative contribution of major sources to PM10 in Collie during 2006/

2007 (Data source: http://www.npi.gov.au).

1.1.4 Future sources of particles in Collie

The ongoing expansion of the energy industries in Collie will lead to additional sources of particles. At present, the following are under construction:

• Bluewaters Power Station Phase I – Griffin Energy is constructing a 200 MW sub critical coal-fired power station on a site 4 km north-east of Collie.

• Bluewaters Power Station Phase II – Griffin Energy is also beginning construction on another 200MW coal-fired power station adjacent to Phase I.

1.2 Health impacts of particles

Many anthropogenic and natural sources emit particles directly or emit other pollutants that react in the atmosphere to form particles. Generally, any activity that involves burning of materials or any dust generating activities are sources of particles. The relative contribution of each source type varies from day to day, depending on meteorological conditions and quantities of emission from mobile and static sources.

The range of adverse health effects associated with particle pollution is broad and includes various respiratory, cardiopulmonary, and cardiovascular diseases and mortality from a variety of causes (US EPA, 1996a, b). Inhalable particles such as PM10 and PM2.5 are associated with increases in respiratory illness (e.g. asthma, bronchitis and emphysema). Particles as PM2.5 are thought to represent a particular risk due to their ability to penetrate further into the lungs and be absorbed in the bloodstream.

Some people are more sensitive than others – for example, the elderly and those suffering from pre-existing heart or lung disease. The young are also

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sensitive, with evidence of increased frequency of respiratory tract infections, coughing and wheezing following exposure to airborne particles. Recent research has also linked exposure to relatively low concentrations of particles with premature death (WHO, 2003).

2.0 AUSTRALIAN AIR QUALITY STANDARDS AND SCREENING PROCEDURES FOR PARTICLES

In Australia in 1998, the National Environment Protection Council (NEPC) introduced an ambient air quality National Environment Protection Measure (NEPM) which set out air quality standards applicable to all states and territories. The standards cover six pollutants, including PM10. Air NEPM standards for particles are summarised in Table 1. The NEPM air quality standard for PM10 is 50 µg/m³ averaged over one day with five exceedence days allowed each year (NEPC, 2003).

While there are no NEPM air quality compliance standards for PM2.5, the NEPC has recommended an ambient air quality advisory reporting standard of 25 µg/m³ averaged over one day and 8 µg/m³ measured as an annual average. There have been no allowable exceedences set for PM2.5 with the goal being to gather sufficient data to facilitate a review of the standards.

Table 1 Air NEPM standards for particles Averaging

period

Concentration Allowable exceedences

(NEPM goal)

PM10 1 day 50 µg/m³ 5 days/year

PM2.5 1 day

1 year 25 µg/m³

8 µg/m³

A screening procedure to determine the necessity for continued monitoring within a region was developed by the NEPC Peer Review Committee (NEPC, 2001a). This screening procedure was in the form of an acceptance limit and was set at 65 per cent of the Air NEPM standard (i.e. 32.5 ug/m³averaged over on day for PM10) for 2-4 years of data. Compliance with the screening procedures is determined by using historical data within a region the purpose being to demonstrate that a full compliment of monitoring stations may not be required within a particular region either to detect exceedences or gain a more representative depiction of pollutant distribution. (NEPC, 2001a).

The screening limit for PM10 will apply to the 5^th highest daily reading, where the higher readings can be shown to be due to bushfires or controlled burns.

This is consistent with the procedure developed by the NEPC Peer Review Committee.

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3.0 SAMPLING LOCATION AND MONITORING METHOD

Ambient PM10 and PM2.5 data assessed in this study has been taken from the Roche Park monitoring station (Figure 1) in Collie. This monitoring station is situated on the outskirts of Collie at the corner of, Gibbs Road and Paul Street. The main land use around the station is residential land and remnant native vegetation. The station was established in 1985 by Verve Energy.

The monitoring station uses the TEOM (Tapered Element Oscillating Microbalance) method of sampling and is operated and calibrated in accordance with the Australian Standards (AS) 3580.9.8-2001. The TEOM draws air through a hollow tapered tube, with the wide end of the tube fixed, while the narrow end oscillates in response to an applied electric field. The filter cartridge is at the narrow end of the tube. The sampled airflow passes from the sampling inlet, through the filter, to a flow controller. The flow rate through the sample filter is set at a nominal 3.0 litres per minute (L/min). As particles are collected on the filter, the filter mass changes, resulting in a change of the natural oscillating frequency of the tapered tube. Using the rate of mass accumulation on the filter and the flow rate through the sample (main) flow controller, the TEOM’s microprocessor calculates the mass concentration.

4.0 RESULTS AND DISCUSSION

Ambient data for PM10 and PM2.5 from the Roche Park monitoring site in Collie has been analysed from the 1 January 2004 until 31 December 2007. Data capture in every year except 2005 was above a 95 per cent capture rate (Table 2 and 3) and is considered sufficient to enable comparison of the data against the Air NEPM standard. The annual data availability for this report is based on the number of valid hourly data of particle concentrations. The high data availability also allows calculation of seasonal effects in the behaviour of airborne particles (NEPC, 2001).

4.1 Comparison with Air NEPM standards

All the valid ambient PM10 and PM2.5 data for the period (2004-2007) were compared to the standards outlined by Air NEPM (Table 1) and the screening acceptance limit (for PM10 only). The results are discussed below.

4.1.1 PM10 concentration

Table 2 shows comparison of the daily average PM10 concentration with the essential requirements of the Air NEPM standard and its acceptance limit.

Daily average PM10 concentration exceeded the Air NEPM standard of 50 µg/m³ twice in 2004 and 2007, once in 2005 and nine times in 2006.

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The Roche Park monitoring site did not meet the Air NEPM goal of no more than five exceedences per year in 2006. The site also did not meet the screening procedure acceptance limit where the fifth highest daily concentration is required to be less than 65 per cent of the Air NEPM standard.

Table 2 Particles, as PM10, 24-hour average concentration and compliance

Year Data

recovery Number of days air

NEPM standard

was exceeded

Was NEPM goal met?

Number of days acceptance

limit was exceeded

Was acceptance

limit met?

2004 2005 2006 2007

99%

49%

99%

2 1 9 2

Yes Incomplete

No Yes

19 9 26 20

No No No No Figure 3 compares the daily average PM10 concentration to the standard set by the Air NEPM and acceptance limit for the years with the highest data recovery (i.e. 2004, 2006 and 2007).

Figure 3 PM10 daily concentration at Roche Park

The maximum daily concentration of PM10 of 116.8 µg/m³ was recorded in April 2004 while the minimum concentration was 5.1 µg/m ³ recorded in November 2004.

As there is no Air NEPM standard for the annual concentration of PM10,the annual average concentration was compared to the World Health Organisation (WHO) standard of 20 µg/m³ (WHO, 2005). In general, annual average concentration of PM10 is lower than the WHO standard (Table 5) but in 2006 it exceeded the standard by 5 per cent.

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4.1.2 PM2.5 concentration

Table 3 shows the daily average PM2.5 concentration compared to the Air NEPM advisory reporting standard of 25 µg/m³. The daily averaged concentration of fine particles exceeded advisory standard 10 times in 2004, three times in 2005, 13 times in 2006 and nine times in 2007. Annual average concentration of fine particles exceeded the Air NEPM standard in each of the years studied.

Table 3 Particles, as PM2.5, 24-hour average concentration and compliance Year Data recovery Number of days

advisory air NEPM standard was

exceeded 2004

2005 2006 2007

98%

49%

99%

10 3 13

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4.2 Temporal Variation

The following section provides an analysis of PM10 and PM2.5 concentrations at the Roche Park monitoring site in Collie during January 2004 to December 2007. The objective was to determine the diurnal and seasonal patterns of PM10 and PM2.5 with the aim of identifying the main emission sources and meteorological factors responsible for these patterns.

4.2.1 PM10 and PM2.5 concentration at Roche Park

Tables 4 and 5 summarise PM10 and PM2.5 concentrations respectively from the Roche Park monitoring site.

The maximum daily concentration of PM10 decreased from 116.8 µg/m³ in 2004 to 79.2 µg/m³ in 2007. The annual average concentration increased by 7 per cent from 2004 to 2006^∗, however, in 2007 the annual average fell to 18.4 µg/m³. The median PM10 concentration shows slight variation from year to year with the maximum value occurring in 2006.

Table 4 Summary of PM10 concentration at Roche Park, (µg/m³) Year Annual

average

Maximum 6^th highest

90^th percentile

Median Minimum 2004

2005 2006 2007

19.6 18.9 21.0 18.4

116.8 56.4 88.8 79.2

43.5 36.9 69.6 40.0

28.8 28.9 30.9 26.9

17.8 17.1 18.3 16.6

5.1 5.3 7.4 6.3

∗ Data for 2005 is incomplete.

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Table 5 Summary of PM2.5 concentration at Roche Park, (µg/m³) Year Annual

average

Maximum 95^th percentile

90^th percentile

Median Minimum 2004

2005 2006 2007

10.7 10.1 10.7 9.0

105.9 45.4 73.2 66.7

20.6 18.5 19.7 17.3

16.5 16.3 16.1 13.4

8.8 8.4 8.6 7.6

3.4 3.5 3.2 3.2 The lowest annual average concentration of PM2.5 was observed in 2007 with a value of 9.0 µg/m³. The maximum daily concentration of PM2.5 was recorded in 2004 with a value of 105.9 µg/m³. The 90^th percentile decreased from 16.5 µg/m³ in 2004 to 13.9 µg/m³ in 2007. The percentile results give an indication of underlying trends and exclude the influence of extraordinary events.

Monthly percentiles of ambient PM10 and PM2.5 data were estimated for each month during the study period and the results are graphed in Figures 4 and 5.

Figure 4 Daily averaged percentiles for PM10, during 2004 - 2007

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Figure 5 Daily averaged percentiles for PM2.5, during 2004 – 2007

The maximum monthly average concentration for PM10 and PM2.5 occurs between April and June and October to December.

4.2.2 Seasonal and daily variation

The data from Roche Park, Collie was divided into summer, winter, autumn and spring and further subdivided into day time (7am-6pm) and night time (7pm-6am). These are shown in Tables 6 and 7.

Table 6 Seasonal PM10 concentrations (in ug/m³)

Summer Autumn Winter Spring

day night day night day night day night 2004 20.8 17.9 23.3 27.6 14.3 17.4 16.7 16.1 2005 25.3 21.7 n/a n/a 14.5 17.3 n/a n/a 2006 21.1 19.3 23.1 24.6 18.9 21.2 19.6 18.2 2007 23.8 19.9 21.5 22.2 13.6 16.5 16.8 18.2

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Table 7 Seasonal PM2.5 concentrations (in ug/m³)

Summer Autumn Winter Spring

day night day night day night day night 2004 8.1 7.5 11.8 14.9 9.0 13.4 8.1 9.1

2005 9.5 9.0 n/a n/a 8.9 12.9 n/a n/a

2006 8.8 9.6 10.8 15.0 10.1 14.6 8.5 9.7 2007 8.2 7.8 9.4 12.7 7.2 11.0 7.7 10.5 It can be seen from Tables 6 and 7 that in general, the highest concentration of PM10 and PM2.5 occurs in autumn. This correlates well with the highest number of exceedences registered during this season (as depicted in Appendix 1).

It is also clear from Tables 6 and 7 that during autumn and winter, both PM10

and PM2.5 particles exhibit a higher concentration at night time than during the day time. It is likely that the higher night time particle concentrations may be due to a high frequency of nocturnal inversions and, as a consequence pollution being trapped above the surface (BoM, 1998). This is graphically demonstrated in Figure 6 showing the regular cycle of the day:night particle ratios during each season.

Figure 6 Day:night particle ratios during each season

Seasonal wind roses for Collie in Figure 7 show that in summer, winds prevail from the east-south-east. A number of the industrial facilities (Figure 1) are

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located in this direction (i.e. upwind of the monitoring station). In contrast, winter winds are predominantly from the north-west, from the direction of Collie town site. It maybe that residential activity and home heating could impact the particle concentrations in winter. In autumn and spring, no particular wind arc dominates (Figure 8). The highest frequency (37.1 per cent) of calm conditions occurs in winter.

Summer Season Autumn Season

Winter Season Spring Season

Figure 7 Seasonal wind roses for Roche Park monitoring site (2004-2007)

4.2.3 Diurnal variation of particle concentrations in winter and summer

Figure 8 shows the diurnal patterns of particles during summer and winter.

The graph shows one-hour averaged 100^th (maximum), 99^th, 95^th, 90^th and 50^th (median) percentile levels for each hour of the day. During summer PM10

generally starts increasing from about 6 am onwards, peaking around 9 pm and then declines overnight. Typically in summer, the minimum concentration occurs in the early morning hours.

In contrast, the diurnal variability of both PM10 and PM2.5 in winter is characterised by two periods of elevated concentration: one during the morning at 9 am and one later in the day between 6 and 7 pm. The PM10

concentration after 7 pm remains generally steady into the night and declines into the early hours of the morning while the PM2.5 continues to rise, declining only after midnight. A possible reason for these trends is that throughout the night, pollution becomes trapped in the nocturnal inversion layer above the surface. In the morning, a breakdown of the inversion layer can transport

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particles down to the surface where high concentrations may last for a few hours. Also, these peaks may be the result of increased transportation and residential (home heating) emissions during the early morning and evening hours.

PM10 Summer profile PM2.5 Summer profile

PM10 Winter profile PM2.5 Winter profile

Figure 8 Diurnal variation of PM10 and PM2.5 for winter and summer (2004- 2007)

(maximum concentrations in Figure 8 have been truncated to better display the characteristics of lower percentiles)

4.3 Comparison with other monitoring stations

By way of comparison the particle data from Collie was compared with monitoring data from DEC operated monitoring stations in Duncraig and Bunbury.

The Duncraig monitoring station is located in a northern metropolitan suburb of Perth, and is considered an upper bound performance monitoring station measuring PM¹⁰from a combination of vehicle and wood heater emissions during stable meteorological conditions. PM10 monitoring started in Duncraig 1994, while PM2.5 monitoring started in 1995. The site was established as part of the Perth Photochemical Smog and Haze Studies. Bunbury station (160 km south of Perth) was established in the south-west region to determine the

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impact of land management activities on key regional centres and commenced monitoring PM2.5 and PM10 in 1997 and 1999, respectively. The Bunbury monitoring station is a suburban site and will remain in use at this location indefinitely with the intention of developing long term trend data.

4.3.1 Comparison with Air NEPM standards

Table 8 contains the daily peak 24-hour PM10 and the number of exceedences for each year 2004 to 2007 at Collie, Duncraig and Bunbury. Collie had two exceedences in 2004 and 2007 with one and nine exceedences in 2005 and 2006 respectively. Bunbury had four exceedences in 2004, three in 2005 and three in 2006 when the peak daily concentration reached 123.5 µg/m³. Duncraig had the least number of exceedences with one in 2005.

Table 8 Peak daily averaged PM10 concentration (µg/m³) and number of exceeedences for 2004-2007

Collie Duncraig Bunbury

Daily peak

Number of exceedences.

Daily peak

2004 116.8 2 45.1 0 99.5 4

2005 56.3 1 59.2 1 63.3 3

2006 88.8 9 40.6 0 123.5 3

2007 79.2 2 40.3 0 46.5 0

Table 9 contains the daily peak 24-hour PM2.5 and the number of exceedences for each year 2004 to 2007 at each monitoring station. Collie had the highest number of exceedences (10 in 2004, 3 in 2005, 13 in 2006 and 9 for 2007). Duncraig had three exceedences in 2005 and two in 2006.

Bunbury had five exceedences in 2004 and 2005, eight in 2006 and three in 2007.

Table 9 Peak daily averaged PM2.5 concentration (µg/m³) and number of exceeedences for 2004-2007

Collie Duncraig Bunbury

Daily peak

2004 105.8 10 24.4 0 94.8 5

2005 45.4 3 40.6 3 64.2 5

2006 73.2 13 33.4 2 113.5 8

2007 66.7 9 19.6 0 34.5 3

Table 10 depicts the annual averaged concentration of fine particles in Collie, Duncraig and Bunbury for 2004-2007. The Air NEPM Advisory standard for particles as PM2.5 of 8 µg/m³ averaged over one year was exceeded Duncraig in 2006 and Bunbury in 2004, 2005 and 2006. The annual concentration in Collie exceeded the Air NEPM advisory standard by between 15-35% for each

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year of the study. For the south-west region in general, the annual average of PM2.5 is relatively higher than in Perth.

Table 10 Annual averaged PM2.5 concentrations (µg/m³) for 2004-2007 Monitoring

station

2004 2005 2006 2007

Collie 10.7 10.1 10.7 9.0

Duncraig 7.9 7.8 8.2 7.3

Bunbury 9.2 8.6 8.7 7.8

A comparison of the three sites for both PM10 and PM2.5 are presented in Figures 9 and 10. Although the maximum PM10 and PM2.5 concentration for 2005 and 2006 is highest in Bunbury, the 95^th, 90^th and median percentiles are at their maximum in Collie for all years.

Figure 9 Daily averaged particles as PM10 in Collie, Bunbury and Duncraig

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Figure 10 Daily averaged particles as PM2.5 in Collie, Bunbury and Duncraig

4.3.2 Mass ratio

Table 11 gives the mass ratio of particles (PM2.5/PM10) during the different seasons in Collie and at a number of other urban/residential sites in Western Australia.

It can be seen that on average, PM2.5 accounted for between 40 and 65 per cent of PM10. The PM2.5/PM10 mass ratios were relatively low (<0.45) during summer, indicating that the PM10 minus PM2.5, also known as coarse particles, were a relatively large portion of PM10. On the other hand, at Collie 65 per cent of the PM10 mass is composed of PM2.5 particles during winter (Table 11). This figure is compared with PM2.5/PM10 mass ratios recorded in Duncraig, and Bunbury.

Table 11 Ratio of PM2.5 to PM10 in Collie, Duncraig and Bunbury for 2004- 2007

Monitoring site Summer Autumn Winter Spring

Collie² 0.40 0.54 0.65 0.51

Duncraig 0.44 0.50 0.55 0.48

Bunbury 0.42 0.49 0.50 0.48

4.4 Back trajectories

To investigate a relationship between particle concentrations and wind characteristics, which are considered to be one of the most important explanatory variables, wind trajectories were back-plotted for those days when

2The values for autumn and spring 2005 were not included for Collie

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both PM10 and PM2.5 exceeded 24-hour NEPM standards. Results are shown in Appendix 2.

The wind trace displayed in each map indicates the trajectory or path of air pollutants to the receptor. Wind speed determines the distance from the source to the receptor and also the time taken for the ambient pollutants to reach the receptor.

The back-trajectories enable tentative identification of the source of the pollution on the given day. As discussed in Appendix 2 the wind trajectories indicate that an apparent contribution to the particle exceedences experienced in Collie were controlled burns and private burns.

It is interesting to note that the ratios of PM2.5/PM10 in Appendix 2 are significantly different from the ratios estimated for the seasons shown in Table 11. This is understandable given most of the particles in the events discussed in Appendix 2 were generated by some form of combustion where the vast majority will be in the 2.5um fraction. Seasonal ratios, by their very length (3 months), incorporate both combustion events and anthropogenic sources such as wind borne dust and soil which tend to have a higher proportion of course particles.

5.0 CONCLUSIONS

An assessment of ambient particle data (PM10 and PM2.5) was conducted for the period 2004-2007 with the aim to identify the need for future monitoring in the Collie area. Analysis indicates that the daily average concentration of PM10 exceeded the Air NEPM standard on an average of four days a year.

However, in 2006, the daily average exceeded the Air NEPM standard on nine days. There were 20 days on average during the study period (2004- 2007) when the daily average PM10 concentration exceeded the NEPM screening level acceptance limit.

The daily average concentration for PM2.5 exceeded the Air NEPM advisory standard 10 times in 2004, 3 times in 2005, 13 times in 2006 and 9 times in 2007. When compared to Bunbury and Duncraig, Collie has the highest number of exceedences for both PM10 and PM2.5.

Airborne particles exhibit distinct seasonal and diurnal patterns. The highest concentration of PM10 and PM2.5 along with the highest number of exceedences occurred in autumn.

The study shows particle concentrations in Collie exceeded the advisory reporting standard for PM2.5, and also recorded the highest number of exceedences when compared to Bunbury and Duncraig.

Results from the back trajectories analysis suggest that the most, if not all, of the PM10 and PM2.5 exceedences were associated with emissions from fires.

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area and potential sources of particles, which will also contribute to ambient concentrations. In some cases residential premises are located close to industrial operations. The area also includes transport related combustion sources such as domestic vehicles and heavy vehicles associated with industrial operations (including open-cut mines). All of these sources, under adverse meteorological conditions could affect the particle concentrations at the Roche Park monitoring station.

A draft of this report was critically reviewed by staff from the Marine and Atmospheric Research Division of CSIRO. Following the review it was recommended that particle sampling should be carried out, especially, during periods of high PM10 and PM2.5 to determine the chemical composition of the samples. Results from this could include gravimetric mass concentration, organic carbon and elemental carbon concentration and estimation of the biomass burning contribution to PM10 and PM2.5 by use of chemical tracer,

such as levoglucosan.

It is recommended to continue the active monitoring of PM10 and PM2.5 at Roche Park to give a longer temporal record in Collie, especially to assess any changes made to the power stations in future.

DEC has also installed a monitoring station in Collie in March 2008. This site has a PM10 TEOM and includes meteorological data. This site is close to the centre of town and will remain in place for the foreseeable future.

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References

Bureau of Meteorology (BoM) 1998, Aspects of meteorological factors affecting atmospheric dispersion in Perth area, Climate and Consultancy section, Western Australian Regional Office www.bom.gov.au.

Environmental Protection Authority South Australia 2006, Ambient Air Quality in Port Pirie South Australia Monitoring Campaign 2002 – 2005, EPA South Australia.

Environmental Protection Authority South Australia 2005, South Australia’s ambient air quality monitoring program- a review. Adelaide, South Australia.

DEC 2005, Western Australia Air Monitoring Report 2004, Technical Series 122, Perth, Western Australia.

http://portal.environment.wa.gov.au/portal/page?_pageid=54,1258040&_dad=portal&_schem a=PORTAL.

DEC 2006, Western Australia Air Monitoring Report 2005, Technical Report AQM 1, Perth, Western Australia.

DEC 2007, Western Australia Air Monitoring Report 2006, Technical Report AQM XXX (Un-published report), Perth, Western Australia.

Keywood, M.D., Ayers, G.P., Gras, J.L., Gillett, R.W. and Cohen, D.D. 2000, Size Distribution and Sources of Aerosol in Launceston, Australia, during winter 1997, Journal of the Air and Waste Management Association, Vol 50, 418-427.

NEPC 2007, Review of the National Environment Protection (ambient Air Quality) Measure. Discussion Paper prepared for the National Environment Protection Council.

NEPC 2003, National Environment Protection (Ambient Air Quality) Measure. Office of Legislative Drafting, Attorney-General’s Department, Canberra

NEPC 2001a, National Environmental Protection Council (ambient Air Quality) Measure Technical Paper No. 4 Screening Procedures.

<www.ephc.gov.au/nepms/air/pdf/TP4_Screening_Procedures_Revised 2001.pdf >.

NEPC 2001b, National Environment Protection (Ambient Air Quality) Measure Technical Paper No. 5 Data Collection and Handling.

<www.ephc.gov.au/nepms/air/pdf/TP5_Data_Collection.pdf >.

NEPC 2001c, National Environment Protection (Ambient Air Quality) Measure Technical Paper No 10 Collection and Reporting of TEOM PM10 Data.

< www.ephc.gov.au/nepms/air/pdf/TP10_Collection_&_Reporting.pdf>.

Sinclair Knight Mertz (SKM) 2005, Collie Power Station Expansion Air Quality Assessment – Air Quality Modelling and Screening Air Quality Health Risk Assessment, Report prepared for Western Power, Griffin Energy and Collie Power Consortium.

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Synovate 2006, Home Heating Survey, Department of Environment and Conservation, Perth.

Todd, J 2005, Cost-benefit analysis of wood smoke reduction in Perth, Prepared for the Department of Environment and Conservation (WA), Eco-Energy Options Pty Ltd.

Revised edition 2006.

US EPA 1996a, AP-42 Compilation of Air Pollutant Emission Factors Vol 1 Stationary Point and Area Sources, United States Environmental Protection Agency.

US EPA 1996b, Air Quality Criteria for Particulate Matter, Office of Research and Development, Environmental Protection Agency, EPA 600/P-99/002a, b and c.

World Health Organisation (WHO) 2005, Air Quality guidelines for particulate matter, ozone, nitrogen dioxide and sulphur dioxide.

World Health Organisation (WHO) 2003, Health aspects of Air pollution with particulate matter, ozone and nitrogen dioxide, Report on a WHO Working Group, Bonn, Germany 2003.

Websites

http://www.bom.gov.au/climate/averages/tables/cw_009628.shtml)

www.npi.gov.au www.epa.wa.gov.au

www.ephc.gov.au/nepms/air/air_nepm.html http://portal.environment.wa.gov.au/

www.euro.who.int/document/e79097.pdf

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Appendix 1 – Box-whisker plot and monthly summaries of

ambient particle concentrations at Roche Park, Collie

monitoring station

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2004 PM10

Monthly summary of PM10 data (2004)

Month Maximum µg/m³

2^nd highest µg/m³

Monthly average

µg/m³

No of daily averages >

50 µg/m³

100 µg/m³

January 29.8 27.3 17.7

February 29.8 28.9 21.3

March 35.0 32.3 22.8

April 116.8 46.8 27.5 1 1

May 87.5 43.5 25.5 1

June 26.7 22.1 16.6

July 25.1 24.6 15.1

August 23.8 23.0 15.8

September 25.2 20.1 15.0

October 25.6 24.9 17.4

November 29.6 27.9 16.9

December 44.8 44.4 24.6

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2004 PM2.5

Monthly summary of PM2.5 data (2004)

µg/m³

25 µg/m³

100 µg/m³

January 12.5 11.6 7.1

February 15.7 14.7 8.7

March 17.9 15.6 8.9

April 105.9 34.9 16.7 5

May 68.0 34.6 17.7 4

June 17.7 17.4 10.6

July 22.7 18.9 11.6

August 19.6 19.5 11.4

September 13.1 12.8 8.9

October 20.6 15.8 9.1

November 11.8 11.6 7.7

December 36.0 25.0 11.3 1

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2005 PM10

µg/m³

50 µg/m³

100 µg/m³

January 36.9 33.0 22.2

February 41.5 40.3 23.9

March April May

June 28.5 27.2 15.0

July 29.9 29.4 17.9

August 26.0 21.4 14.7

September October November

December 56.4 48.6 19.8 1

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2005 PM2.5

µg/m³

25 µg/m³

100 µg/m³

January 23.4 17.2 8.7

February 12.8 11.1 7.7

March April May

June 20.7 20.6 10.5

July 22.7 20.4 12.1

August 18.1 17.5 10.0

September October November

December 45.4 37.0 11.1 3

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2006 PM10

µg/m³

50 µg/m³

100 µg/m³

January 34.6 33.0 18.7

February 33.8 31.7 22.0

March 36.0 32.2 23.6

April 26.6 26.2 15.7

May 88.8 81.8 32.4 6

June 78.3 66.9 27.2 2

July 33.2 26.4 17.1

August 57.6 24.4 16.6 1

September 25.3 24.0 15.4

October 45.5 42.7 22.4

November 30.3 28.7 18.8

December 35.6 34.3 22.2

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2006 PM2.5

µg/m³

25 µg/m³

100 µg/m³

January 19.0 14.5 7.6

February 16.0 15.3 8.6

March 15.7 13.4 8.1

April 15.7 12.1 7.9

May 73.3 67.0 22.9 7

June 55.8 53.0 16.0 2

July 20.4 20.4 10.9

August 44.7 16.6 10.5 1

September 13.0 12.7 8.5

October 29.3 25.5 10.7 3

November 18.1 15.7 8.0

December 17.1 14.7 8.9

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2007 PM10

µg/m³

50 µg/m³

100 µg/m³

January 36.8 35.9 19.0

February 36.5 36.4 24.1

March 31.6 29.7 20.8

April 40.0 35.3 19.5

May 79.2 45.9 24.9 1

June 23.5 19.3 14.1

July 25.5 24.1 16.1

August 27.2 24.9 15.1

September 23.4 21.6 14.2

October 74.7 34.5 16.8 1

November 47.6 30.9 21.5

December 25.2 23.9 14.5

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2007 PM2.5

µg/m³

25 µg/m³

100 µg/m³

January 13.8 12.9 7.3

February 11.3 11.1 7.7

March 9.2 8.7 7.0

April 19.6 17.0 9.1

May 66.7 40.4 17.0 7

June 19.8 13.1 8.5

July 20.1 14.3 9.0

August 18.0 17.5 9.8

September 13.4 12.2 8.6

October 58.1 23.4 9.3 1

November 35.2 15.2 9.4 1

December 8.2 8.0 5.6

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Appendix 2 Back-trajectories for exceedences of the

NEPM PM

10

standard and the NEPM PM

2.5

advisory

standard.

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PM10 and PM2.5 exceedences on 28 April 2004

MODIS hotspot detection Terra-1 APR 28 22:20 2004 WST

Pollutant

PM10, PM2.5

Monitoring site

Collie

Daily averaged concentration

PM10 116.8 µg/m³

PM2.5 105.9 µg/m³

Ratio PM2.5/PM10 0.91

NEPM standard

PM10: 50 µg/m³ PM2.5: 25 µg/m³

Description of event

The wind trajectory and measurements of wind speed and directions indicate a possible cause to the PM10 and PM2.5

exceedences in Collie was controlled burns at Davis (20 km south-east of Collie), Mungalup (17 km north-east of Collie), Westralia (2 km west of Collie) and Yabberup (25 km south-west of Collie) as shown by satellite map (the fires as red crosses in the region of interest).

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PM10 and PM2.5 exceedences on 5 May 2004

MODIS hotspot detection Aqua-1 MAY 05 00:56 2004 WST

Pollutant

PM10, PM2.5

Monitoring site

Collie

Daily averaged concentration

PM10 87.5 µg/m³

PM2.5 68.0 µg/m³

Ratio PM2.5/PM10 0.78

NEPM standard

PM10: 50 µg/m³ PM2.5: 25 µg/m³

Description of event

The wind trajectory and wind speed and directions observations indicate the likely cause to the PM10 and PM2.5

exceedences in Collie was controlled burns 30 km east of Harvey which started to burn on 4 May 2004 and continued to the next day. The satellite map shows the fires as red crosses in the region of interest.