State of the Environment Report 2007
Airborne particulates (or particles) are produced by a wide range of natural phenomena and human activities, and may be solid or liquid (a suspension of solid and liquid particles is often called an aerosol). Natural sources of particulates include fine soil mobilised by wind erosion, sea salt blown from the ocean, and smoke from bushfires. Human generated sources of particulates include combustion processes in motor vehicles (especially diesel), industrial and commercial boilers and incinerators, power generation plants, mining operations, solid fuel domestic heating, domestic incineration and burning of vegetation (including agricultural and fuel reduction burning).
Particulate size is the main determinant of pollutant behaviour, and is usually expressed in terms of the 'aerodynamic diameter'. Particulates are commonly categorised or classified (Department of Environment, 2003a) as follows:
Large inert particulates are typically associated with adverse aesthetic and environmental effects rather than health effects. Inhalable particulates (PM10 and smaller) are associated with increases in respiratory illness (e.g. asthma, bronchitis and emphysema). Smaller particulates, such as PM2.5 are thought to represent a higher risk due to their ability to penetrate further into the lungs and be absorbed into the bloodstream (Department of Environmental Protection, 2000a). A significant positive relationship exists between air pollutants and daily hospital admissions for respiratory disease, cardiovascular disease and respiratory hospitalisation of the elderly in particular (Department of Environment, 2003b). Particulates have been responsible for the majority of NEPM exceedences recorded since 1998.
There are standards in place for particulates via the National Environment Protection (Ambient Air Quality) Measure (NEPM) to ensure community health is not compromised. They include:
Both sizes of particulates are monitored at Caversham, South Lake, Duncraig (Figure A0.2), Bunbury and Busselton (PM2.5 only). Exceedences of NEPM standards occur occasionally, but the standard allows up to five exceedences per year. As examples, levels of particulates PM10 and PM2.5 are shown for Bunbury and the Perth metropolitan suburb of Duncraig (Figures A3.1, A3.2, A3.3 and A3.4 respectively). Exceedences of NEPM standards have occurred frequently at both sites. The common cause of exceedences at Bunbury and other South West sites is smoke caused by bushfires (summer), bushfire hazard reduction burns (other times of the year), and domestic wood heaters. Particulates measured at the Duncraig site are mostly from traffic emissions, sea salt and wood heaters (especially during winter).
![Figure A3.1: Ambient yearly range of PM10 levels at Bunbury air quality monitoring station, compared with the Australian standard for exposure. [Data source: Department of Environment and Conservation.]](/site/files/images/Figure-A3.1_Large.jpg)
![Figure A3.2: Ambient yearly range of PM2.5 levels at Bunbury air quality monitoring station, compared with the advisory reporting standard for exposure. [Data source: Department of Environment and Conservation.]](/site/files/images/Figure-A3.2_Large.jpg)
![Figure A3.3: Ambient yearly range of PM10 levels at Duncraig air quality monitoring station, compared with the Australian standard for exposure. [Data source: Department of Environment and Conservation.]](/site/files/images/Figure-A3.3_Large.jpg)
![Figure A3.4: Ambient yearly range of PM2.5 levels at Duncraig air quality monitoring station, compared with the advisory reporting standard for exposure. [Data source: Department of Environment and Conservation.]](/site/files/images/Figure-A3.4_Large.jpg)
The Air Quality in Perth: 1992-2002 (Department of Environmental Protection, 2003) study found that annual mean daily maximum 24-hour total suspended particulate concentrations at monitoring stations fell during the study period, ambient PM10 did not change and PM2.5 levels fluctuated. Visibility readings around Perth also fluctuated, with bushfire events, controlled burns and domestic wood combustion being major contributors to poor visibility.
Data from industry monitoring sites are also collected at some locations (Table A3.1). High particulate levels frequently occur in the Pilbara and Kimberley due to bushfires, but dust generated from wind erosion and mining activities is also significant. Port Hedland has traditionally had high loads of particulate matter due to past port management practices, planning decisions and the arid climate of the area. The Pilbara Air Quality Study (Department of Environment, 2004a) found that the concentration of particulates (as PM10) at Boodarie (near Port Hedland) and Dampier was generally high. Exceedences of the NEPM standard were caused by 'background' sources such as dust storms and bushfires, but dust from ore handling facilities and other industry activities in the immediate vicinity of the town were dominant. The ratio of PM10 to PM2.5 particles is lower than that generally found in Perth, indicating that Pilbara air generally contains coarser particulate matter. Karratha is also well known for having high particulate levels. However, there is no current monitoring of particulate matter in the Pilbara or Kimberley regions.
![Table A3.1: Summary of PM10 exceedences of the Australian standard at sites outside the Department of Environment and Conservation monitoring network in Western Australia. [Data source and notes: (a) Department of Environment (2004a). The monitoring was for only 166 to 225 days per year at Boodarie (background site) and from 166 to 286 days at the hospital site. Therefore both will understate the actual number of exceedences per year. See Figure 4.3 on p. 10 of this reference. (b) Department of Environment (2005a). A Grieco (Department of Environment and Conservation, pers. comm.) confirmed that monitoring commenced in mid 1998, but only the two complete years have been used for the analysis. (c) Sinclair Knight Merz (2005). (d) Department of Environment (2005b). (e) Sinclair Knight Merz (2003).]](/site/files/images/Table-A3.1_Large.jpg)
Wood heaters are a cause of particulate matter in the Perth airshed especially in winter. The National Woodheater Audit Program (Department of the Environment and Heritage, 2004a) found that 58% of wood heaters failed to meet Australian and New Zealand standard (Standards Australia and Standards New Zealand, 1999) on particle emission limits, 55% had serious design faults that could affect performance and 72% had labelling faults that could affect emissions performance. In addition to faults in appliances, Todd (2003) found that incorrect operation of wood heaters was common, including not using wood correctly or allowing flues to becoming blocked or break down over time.
Comparison between summer and winter readings of particulates (PM2.5 and PM10) for the Perth suburb of Duncraig over time reveal the different types of particulates that make up the air column (including from wood heaters, dust and salt). Concentrations of the larger PM10 particles peak in summer due to presence of dust and sea salt. Smaller PM2.5 particles generally peak in winter, reflecting low background levels (due to rain washing particulates out of the airshed) but more frequent smoke events due to wood heater emissions.
The Perth Airshed Inventory Update 1998-1999 (Department of Environmental Protection, 2002b), followed an earlier study in 1992-93 to contrast the estimated emissions for PM10 from a range of sources (Figure A3.5). Burning vegetation (from bushfires or controlled burns) was considered in the area-based (or diffuse) sources and emission estimates but did not change between 1992-93 and 1998-99. In contrast emissions from motor vehicles, and industrial and commercial sources increased by 174% (Department of Environmental Protection, 2002b). The move towards direct-injection petrol engines and possibly diesel engines in passenger cars may have increased particulate emissions. Particulate emissions from industry have traditionally been very difficult to estimate accurately and any estimates for particulate matter are likely to be conservative (Department of Environmental Protection, 2002b). The large increase in PM10 is most likely a result of the exclusion of brickworks as a source of emissions in the 1992-93 inventory (Department of Environmental Protection, 2002b). A change of methodology allowed PM10 emissions from brickworks to be included in the 1998-99 inventory, and included many small and medium businesses that were not included in the previous inventory.
![Figure A3.5: Change over time in estimated amounts and sources of particulate matter (as PM10) in the Perth airshed. [Data source: Department of Environmental Protection (2002b).]](/site/files/images/Figure-A3.5_Large.jpg)
Work on a third inventory of emissions into Perth's airshed is underway, however details are not yet available.
Estimates of particulate emission trends outside Perth are extremely limited. Significant sources of particulate matter in the North West, apart from local industry and mining, are dust storms and smoke from bushfires. Particulate levels can vary markedly from year-to-year depending on the condition of pastures and rainfall. A succession of dry years may lead to more land becoming susceptible to wind erosion, and severe tropical cyclones, heavy rainfall and flooding can scour areas, also leaving them susceptible to erosion. Bushfires (and resultant smoke) can also vary from year-to-year, depending on rainfall and vegetation growth, but are significant as they occur frequently and can burn for long periods of time.
National Environment Protection Measures: were established in 1998 by the National Environmental Protection Council to set uniform standards for ambient air quality. Amongst other pollutants, standards have been defined for PM10 and an 'advisory standard' was implemented in 2003 for PM2.5 (while further research about a suitable standard is undertaken).
Bushfires and prescribed burning: The Perth Air Quality Management Plan (Department of Environmental Protection, 2000a) includes a strategy for reducing emissions and particulates from bushfires and controlled burns in Perth and other areas of the South West. The Smoke Management Liaison Group includes representatives from the Department of Environment and Conservation and the Fire and Emergency Services Authority and meets to reduce the impact of planned burns on air quality and the community. In addition, the Bushfire Cooperative Research Centre and the Department of Environment and Conservation in conjunction with the Bureau of Meteorology have developed a smoke trajectory model to assist decision making regarding planned burning and to reduce the impact of smoke on particulate levels in Perth.
The Perth Airshed Inventory Updates: The Department of Environment and Conservation has contracted work on a third inventory of emissions into Perth's airshed. Two airshed inventories have already been completed in 1992-93 and 1998-99 (Department of Environmental Protection, 2002b).
The Pilbara Air Quality Study: was initiated in 1998 to gain an understanding of air quality, pollutant emissions, and the meteorology influencing transport and dispersion of air pollutants in the Pilbara coastal centres of Karratha-Dampier, Wickham-Cape Lambert and Port Hedland (Department of Environment, 2004a).
Environmental Protection Authority Guidance Statement no. 18: provides information on prevention of impacts on air quality from dust and smoke generated on land development sites, and advises proponents what the Environmental Protection Authority will consider when making an assessment of air quality impacts from land developments.
Community education: The AirWatch program operates in schools and uses school students to make observations and record data about weather and air quality with the intention of increasing awareness of air pollution issues.
TravelSmart: is a community based program that encourages people to use alternatives to travelling in their private car. TravelSmart forms part of the Metropolitan Transport Strategy and aims to reduce car-as-driver trips of Perth residents by 35% over the next 30 years.
The Halt the Haze trial: aimed to increase public understanding of the impact of wood heaters on air quality. It was later expanded to a heater replacement program in several local councils, but the program has since ceased.
Regulations and codes: The Domestic Solid Fuel Burning Appliances and Firewood Supply Regulations were introduced to prohibit the sale of firewood with high moisture content and painted, plastic coated or chemically treated wood. It also regulated the use of any domestic solid fuel heating appliance that does not comply with Australian Standards (Department of Environment, 2004b). The Kwinana Environmental Protection Policy sets total suspended particle standards and limits in the Kwinana region for industrial and residential areas.
A number of health effects are associated with particulates depending on the nature of the pollutant. For example, prolonged exposure to smoke from bushfires can aggravate breathing problems (including coughing, wheezing, asthma and bronchitis), cause watery eyes, and may increase hospital admissions and reduce workplace productivity. Very fine particulates may enter the bloodstream and affect the cardiovascular system. The health effects may worsen if the fine particulates are associated with pollutants, which may cause allergic reactions and permanent lung damage, diseases and cancer in some susceptible individuals. Severe atmospheric particulate problems may cause coat vegetation and reduce photosynthetic ability, clog air conditioning systems, cover roads and buildings and adversely affect tourism potential in an area. Current responses are largely inadequate to deal with the particulate problem on a widespread scale. Without better management in future, health and environmental problems caused by particulates are likely to worsen.
2.13 Implement the Perth Air Quality Management Plan. Although the plan was released in 2000 and much progress made, many parts have yet to be implemented.
2.14 Develop and implement air quality management plans for regional areas. Management plans should be developed for problem regional areas using the Perth Air Quality Management Plan as a model.
