Particulate matter (PM10 and PM2.5): Health effects
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/m3 averaged 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.
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