Where does fine particle pollution come from?
Rapid population growth has created a concurrent rise in fine particle pollution, generated by industry, trucks, coal-fired power stations, cars and other man-made sources.
Nature also generates fine particle pollution in the form of sea spray and wind-blown soil, dramatically illustrated in the September 2009 dust storms that hit Sydney and other areas.
While the human eye cannot see these fine particles - defined as particles with a diameter less than 2.5 micrometres, which is 40-50 times smaller than the diameter of a human hair - high concentrations of them can significantly reduce visibility. In fact, they play a key role in climate variability as they are very efficient in scattering and absorbing solar radiation.
These fine particles can also cause significant health problems, as the human nose and throat are inefficient at filtering them out, meaning they can penetrate deep into the lungs and even our blood stream. The image below provides a size comparison of some common airborne particles.