Outdoor Air Pollution
Outdoor air is also commonly referred to as ambient air.
Sources of air pollution that contribute to poor outdoor air quality are generally caused by combustion processes. This includes motor vehicle emissions, solid fuel burning and industrial processes.
Evaporation of petroleum-based compounds can also contribute to outdoor air pollution. In the summer months, especially for metropolitan Sydney, a significant amount of air pollution is caused by the evaporation of petrol and other fuels from the car fleet and fuel distribution network.
Health alerts are issued on days when pollutant concentrations are high in Sydney, the Lower Hunter and Illawarra.
Common outdoor air pollutants include carbon monoxide, nitrogen dioxide, sulfur dioxide, ground level ozone and particulate matter.
As these pollutants have the potential to cause adverse health effects, standards for maximum concentrations of these pollutants have been set in Australia through the National Environment Protection Measure (NEPM) for Ambient Air Quality.
Air toxics are pollutants known or suspected to cause serious health effects such as cancer. These pollutants are also referred to as hazardous air pollutants. They are present in the air in low concentrations as either gaseous, aerosol or particulate pollutants.
In Australia, a National Environment Protection Measure (NEPM) for Air Toxics has been developed to provide a framework for monitoring, assessing and reporting on ambient levels.