Particulate matter (PM10 and PM2.5)
Description
PM10 is particulate matter 10 micrometers or less in diameter, PM2.5 is particulate matter 2.5 micrometers or less in diameter. PM2.5 is generally described as fine particles. By way of comparison, a human hair is about 100 micrometres, so roughly 40 fine particles could be placed on its width.
PM10 and PM2.5 are not used for any application.
Substance details
Substance name: Particulate matter (less than 10 micrometers in diameter or less than 2.5micrometres in diameter)
Synonyms: dust, particulate matter, inhalable particles, respirable particles, smoke, mist
Physical properties
Particles of any substances that are less than 10 or 2.5 micrometres diameter. Particles in this size range make up a large proportion of dust that can be drawn deep into the lungs. Larger particles tend to be trapped in the nose, mouth or throat.
Chemical properties
The chemical properties vary depending on sources of particles. It is important to note that particulates are not one particular chemical substance but a classification of particles by size rather then chemical properties.
Further information
The National Pollutant Inventory (NPI) holds data for all sources of Particulate matter (PM10) emissions in Australia.
Description
Recent epidemiological research suggests that there is no threshold at which health effects do not occur. The health effects include:
- toxic effects by absorption of the toxic material into the blood (e.g. lead, cadmium, zinc)
- allergic or hypersensitivity effects (e.g. some woods, flour grains, chemicals)
- bacterial and fungal infections (from live organisms)
- fibrosis (e.g. asbestos, quartz)
- cancer (e.g. asbestos, chromates)
- irritation of mucous membranes (e.g. acid and alkalis)
- increased respiratory symptoms, aggravation of asthma and premature death. The risks are highest for sensitive groups such as the elderly and children.
The factors that may influence the health effects related to exposure to particles include:
- the chemical composition and physical properties of the particles
- the mass concentration of the airborne particles
- the size of the particles (smaller particles may be associated with more adverse effects because they can be inhaled more deeply into the lungs)
- the duration of exposure (short and long term, possibly in years).
Entering the body
Particles in the PM10 size range are commonly present in air and may be drawn into the body with every breath. In the lungs particles can have a direct physical effect and/or be absorbed into the blood. Airborne particles, not only the PM10 fraction, may also may be deposited in the mouth, throat or nose and be ingested.
Exposure
All people are continuously exposed to some extent except in special filtered environments. Exposure may be higher in urban and industrial areas due to an increase in the number of sources, however high levels may also occur in natural environments.
Health guidelines
National Ambient Air Quality Standards:
Under the National Environment Protection Measure for Ambient Air Quality, Australian governments have set a national ambient air quality standard for PM10 of 50 micrograms per cubic metre (50 µg/m3) in outdoor air averaged over a 24-hour period. The goal, to be met by 2008, is for the standard to be exceeded no more than five days a calendar year.
The Measure was varied in 2003 to include advisory reporting standards for PM2.5. These are: 25 µg/m3 averaged over 24 hours; and 8 µg/m3averaged over one year. The goal of the variation is to collect sufficient PM2.5 monitoring data to allow the development of air quality standards.
Workplace exposure:
Currently, the eight-hour time weighted average (TWA) exposure limits are 10 milligrams of inspirable dust per cubic metre of air. Consult with your state or territory workplace safety authority to confirm current guidelines for particulate matter.
Description
PM10 may affect animals in the same way as it affects humans. Particles in general, not specifically PM10 or PM2.5, affect the aesthetics and utility of areas through visibility reduction and may affect buildings and vegetation. The specific effect of particles depends on their composition, concentration and the presence of other pollutants such as acid forming gases.
Entering the environment
Particles in the air affect both the quality of the air and visibility. Once in the air particulate matter generally takes a long time to settle. The particulates may be washed from the air by rain or snow. When they settle on land they may settle permanently or be re-entrained. In water particulates may settle, dissolve or both.
Where it ends up
PM10 and PM2.5 are very fine and light and are therefore easily entrained into the air by wind or disturbances. Chemical changes may occur, as may reactions with other substances, depending on the composition of the particles. Particles may stick together or break apart, changing the size distribution over time.
Environmental guidelines
-
Industry sources
PM10 and PM2.5 are produced from a wide range of industrial processes through bulk material handling, combustion and minerals processing. The industries using these processes include brickworks, refineries, cement works, iron and steel making, quarrying, and fossil fuel power plants.
Diffuse sources, and industry sources included in diffuse emissions data
Particulates are released from a wide range of diffuse sources. Examples include lawn mowing, wood stoves, fires, and wind generated dust, though this tends to be coarser.
Natural sources
Natural sources of PM10 and PM2.5 include bushfires, dust storms, pollens and sea spray.
Transport sources
Vehicles will generate particulates either from direct emissions from the burning of fuels (especially diesel powered vehicles) or from wear of tyres or vehicle-generated air turbulence on roadways. Particles may also be generated from the action of wind on the dusty material that the vehicle may be carrying.
Consumer products
Particulates are not generally included intentionally in any product but may be present as part of the product, for example as part of talc or other powder products.
Sources used in preparing this information
- National Health and Medical Research Council (NHMRC) and the National Resource Management Ministerial Council (NRMMC) (2004), Australian Drinking Water Guidelines 6, accessed July 2007.
- National Pollutant Inventory (1999), Contextual Information.
- Office of the Australian Safety and Compensation Council, Exposure Standards, accessed July 2007.
- Technical Advisory Panel 1999, Final Report to the National Environment Protection Council.
- Technical Advisory Panel 2006, Final Report to the National Environment Protection Council.