Air Pollution

Main Air Pollutants

There are six main air pollutants which are used internationally as indicators of air quality: particles, ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide and lead. These pollutants are known as the 'criteria pollutants' because environment protection agencies set standards for them based on scientific criteria that relate to health and/or environmental effects.

Another class of air pollutants are the 'air toxics', which are hazardous substances occurring in either gaseous or particulate form in the air, and are known or suspected of causing cancer or other serious health effects, such as adverse neurological or reproductive effects. The air toxics include benzene, aldehydes, volatile organic compounds, dioxin, heavy metals, and polycyclic aromatic hydrocarbons (PAH) in particular Benzo[a]pyrene (BaP).

 Pollutant  Sources  Health Effects
biomass and fossil fuel combustion in home heating, industry and motor vehicle engines; cigarette smoke.
In some regions of Australia, particularly during the cooler months, woodsmoke from woodheaters results in elevated particle levels that are a health risk for many in the community.

Upper respiratory tract irritation and infection; exacerbation of and increased mortality from cardiorespiratory diseases. The chemical components of some particles, particularly combustion products, have been shown to cause cancer.
The effects are often more pronounced for vulnerable groups, such as the very young and the elderly.

reaction product of sunlight and vehicle pollutants; hydrocarbons and oxides of nitrogen Eye and throat irritation; reduced exercise capacity; exacerbation of respiratory disease; chest pains can also occur in some people; people with asthma might have more attacks.
Nitrogen Dioxide

fuel combustion at high temperature [eg, from vehicle engines, gas cooking and heating] Eye irritation; upper respiratory tract infection (especially in children); exacerbation of asthma; irritation of bronchi; reduced immunity to lung infections. Children with asthma and older people with heart disease are most at risk.
Sulfur Dioxide

fossil fuel combustion; metal smelting and petrochemical industries; home heating/cooking with coal Throat irritation; exacerbation of cardiorespiratory diseases, including asthma
Carbon Monoxide

biomass and fossil fuel combustion; cigarette smoke and vehicle exhaust Headache, nausea, dizziness, breathlessness, fatigue, visual disturbance, confusion; angina, coma, death; low birthweight (after maternal exposure during pregnancy)
Lead smelters  In children: neuropsychological and cognitive effects.
In adults: hypertension, classic lead poisoning
Air Toxics
motor vehicle emissions; the products of burning fuels, including woodsmoke; industrial emissions;Increase in the incidence of cancer, birth defects, genetic damage, central nervous system defects, immunodeficiency, and disorders of the respiratory and nervous systems.

In Australia, the standards for the criteria pollutants are set by the National Environment Protection Council (NEPC) in the National Environment Protection Measure (NEPM) for Ambient Air Quality. Ambient air quality refers to outdoor air. The NEPM made in June 1998 included only a standard for particles as PM10, but because of the growing evidence for the effect of fine particles on health it was varied in 2003 to add an advisory reporting standard for PM2.5. The NEPM is administered by the Commonwealth, but implemented separately by the individual states under various environment protection acts and air quality management plans. Monitoring is only required in centres with population over 25,000.

Ambient Air Quality NEPM Standards and Goal

Averaging period
Maximum concentration
Goal within 10 years maximum allowable exceedences
Carbon monoxide 8 hours 9.0 ppm 1 day a year
Nitrogen dioxide 1 hour
1 year
0.12 ppm
0.03 ppm
1 day a year
Photochemical oxidants (as ozone) 1 hour
4 hours
0.10 ppm
0.08 ppm
1 day a year
1 day a year
Sulfur dioxide 1 hour
1 day
1 year
0.20 ppm
0.08 ppm
0.02 ppm
1 day a year
1 day a year
Lead 1 year 0.50 µg/m3 none
Particles as PM10 1 day 50 µg/m3 5 days a year
Particles as PM2.5
(Advisory standard)
1 day
1 year
25 µg/m3
 8 µg/m3
goal is to gather sufficient data nationally for a review commencing in 2005

The NEPC made the Air Toxics NEPM in 2004, with the 8-year goal of collecting information to facilitate the development of standards.

Sources of further information