What is particle matter?
When we speak of air pollution, particles are simply small materials that can be suspended or will float in the air. A large collection of
particles is called particle material or sometimes particulates. Particles can be quite large, like sand, or may be too small for us to
see without a microscope.
Most of the particles that we find in our cities are really very complicated mixtures of many different things.
- Dust blown by the wind from soil, stockpiles of building materials, industrial raw materials and products, or from the vehicles
that drive over unsealed or dusty roads;
- Smoke from burning wood, vegetation, oil, waste materials, or gas;
- Pollen grains, bacteria, fungal spores, dust from wheat, barley and other cereals, tiny pieces of skin from animals;
- Dusts and fumes from chemical processes, welding, painting, grit blast cleaning and other industrial processes.
- Fog, mist and "smog", which are really tiny droplets of liquid and sometimes solid particles, formed by natural processes in the atmosphere. They are sometimes called aerosols, which means that the particles are so small that they remain suspended in the air.
In Tasmania, smoke from burning wood in our home heaters is the largest source of particles in the atmosphere during the winter months.
On very still days, wood smoke builds up in the air and we can see that it makes everything hazy. This is because there are so many particles in the air that the sunlight is scattered by the particles.
The levels of particles in Tasmanian cities in summer are usually low unless there are bush fires; however, during the cooler months of the year the levels of particles in the ambient air of many of our towns and cities can exceed the national health-based standard for particles.
Wood-smoke is made partly of tiny droplets of tars and oils distilled from the wood, mixed with many other chemicals escape because the wood has not burned properly. The particles are actually too small to see by themselves but we can see a whole collection of many billions of particles as smoke.
This has been a problem in cities such as Launceston where air gets caught in valleys and the pollution accumulates at
ground level. Launceston's air quality has improved dramatically in recent years and now the maximum particle concentration is rarely
exceeded. Sometimes the reason that we have so much particle material in our air is simply because people are not using their wood heaters
properly. Find out how to improve wood heater use.
Why is particle matter a problem?
A fire that is not burning properly gives off harmful gases and particles and many of these can irritate or harm our lungs. Frequent
exposure to elevated concentrations of fine particles and polluting gases can lead to bronchitis, asthma, heart disease, or for some people,
Particle material is made up of very small particles that can enter our lungs causing irritation, affecting our ability to breathe, and many other problems. We recognise two main types of breathable particle material: PM10 and PM2.5.
The numbers tell us the largest size of the particles in each group in micrometres (millionths of a metre). The particles that are smaller than 10 micrometres in
diameter are called PM10. Particles bigger than PM10 collect in the hairs of the nose and throat and are eliminated by coughing and blowing our nose.
Any particle smaller than 10 micrometres can start its journey down towards the delicate tissue in the lungs. Particles larger than 2.5
micrometres, such as windblown dust and sea salt, are usually trapped in the upper respiratory system. However, particles less than 2.5
micrometres, such as the majority of wood-smoke particles, can make their way right down to the air sacs (alveoli).
There is great concern over deteriorating air quality as it can contribute to many health problems in our community. The very young, the
elderly and those who already have respiratory problems are especially sensitive to high particle concentrations.
The health effects of poor air quality due to wood smoke are far reaching, but principally affect:
- the body's respiratory system - the lungs
- the cardiovascular system - the heart and blood vessels.
At high concentrations these tiny particles can aggravate breathing problems like asthma, bronchitis and infections like pneumonia and in
some cases can cause permanent lung damage or other lung diseases. Individual reactions to air pollutants depend on the type of pollutant
to which a person is exposed, the amount of which the person is exposed, and the individual's health and genetics.
The health effects caused by air pollutants may range from:
- subtle biochemical and physiological changes
- difficulty breathing
- aggravation of existing respiratory and cardiac conditions.
For many of us, smoke will make us cough and may make our eyes and nose run. However, the young, elderly and sensitive populations with
existing conditions of either cardiovascular disease or respiratory disorders such as asthma, emphysema, chronic bronchitis or allergy
problems, may find they become very sick and need special treatment on days when there is a lot of smoke in the air.
These effects can result
in increased use of medication, increased doctor or emergency room visits, more hospital admissions, and even premature death.
As a society, we pay for the health effects of air pollution in many ways. Additional health care costs for the treatment of these effects
may come from:
- hospital admissions
- visits to the emergency room or doctor's office
- homecare service
- medication such as inhalers for asthma.
Other considerations include lost productivity in the workplace, lost wages due to sick time, out of pocket expenses incurred while ill (e.g. additional child care costs), lost quality of life, or ultimately loss of life itself.
Air pollution reduction strategies
Information on additional harmful substances in wood smoke