Air Quality
Smog and Particulates
The two air pollution problems of prime concern in Sydney are photochemical smog and particle pollution.
The term particulate matter (PM) is used to describe airborne solid particles and/or droplets. These particles may vary in size, composition and origin. Based on size, urban PM tends to be divided into three principal groups: coarse PM10, fine PM2.5 and ultra-fine PM0.1 particles.
Fine particles are of most concern to human health because they can be inhaled deeply into the lungs and exacerbate respiratory and cardiovascular illnesses, such as bronchitis, pneumonia and asthma.
Particle pollution is evident as a brown haze that is sometimes seen in cooler months of the year. It is composed of airborne particles of which approximately 24% are from motor vehicles. Finer particles tend to be combustion derived although there are also a number of natural particle sources including sea salt, dust, pollen and bush fires.
Photochemical smog is a whitish haze formed from the action of sunlight on chemical compounds including ozone and oxides of nitrogen. Motor vehicles contribute approximately 80% of nitrogen oxides to the atmosphere. In Sydney, there has been no apparent decrease in ground ozone levels indicating that photochemical smog is still an issue.
The NSW Department of Climate Change and Water (DECCW) maintains an air quality monitoring network that informs the public about air quality. The regional air quality index provides 24-hour summaries, monthly values and annual exceedances. The closest stations to the City are Rozelle, Earlwood and Randwick.
Last Updated: Thursday 30 September, 2010
