AIR POLLUTION

The City of Swan is the largest local authority in the Perth metropolitan area, encompassing an area in excess of 1000 square kilometres, with an estimated population in 2001 of 82,126 (ABS, 2002) which is projected to double by 2021 to 168,100.  Land uses vary enormously and includes urban, agricultural and industrial uses, all of which contribute to air quality problems, along with the regions geographic location at the foot of the Darling Scarp.

Air quality can be affected at the local level (visual amenity, nuisance, health), regional (photochemical smog, haze) as well as the global level (rising greenhouse gas concentrations).  The major contributors to poor air quality are;

• Vehicle emissions
• Domestic emissions (wood heaters, backyard burning)
• Land use practices (clearing, hazard reduction burning, burning of vegetation from land development sites),
• Industrial emissions; and
• Airport emissions.

Photochemical smog - Photochemical smog is normally experienced during summer and is characterised by high levels of ozone at ground level.  It is formed when pollutants, mainly nitrogen oxides and reactive organic compounds (ROC) from motor vehicles, industrial and domestic sources react in the light and heat of the sun to form ozone.  Under severe conditions it appears as a whitish haze. Ozone irritates the mucous membranes in our noses, eyes and lungs. 

Haze - Haze refers to the presence of very small airborne particles.  It occurs primarily in the colder months when smoke from domestic fires and other sources becomes trapped near the ground, resulting in a brown haze.  Another major contributing factor is controlled burns undertaken for fire hazard reduction, land development and backyard burn offs.

Smoke related problems are primarily seasonal, although vehicle emissions remain constant and contribute to haze all year around.  The haze produced from this source is the result of direct emission of particles from petrol and diesel powered vehicles, with emissions from diesel powered vehicles comprising about two thirds of the particle contribution from all motor vehicles (DEP, 1994-1996).

Apart from the loss of visual amenity and odour caused by haze, there are potentially more serious effects on human health related to respiratory and asthma symptoms and even mortality.

© City of Swan 2000-2010