By: Jessica Hefes

Date: 9/8/10

There are different types of air pollutant. sulphur dioxide, nitrogen oxides, ozone, particulate matter, carbon monoxide and lead.

Sulphur dioxide is a colourless gas with a sharp odour. [1] It irritates the nose, nasopharynx and bronchi. It also affects breathing, and can aggravate existing respiratory and cardiovascular problems. Exposure to high concentration of sulphur dioxide weakens the lungs defenses. Children, the elderly, asthmatics and allergy sufferers suffer the most from exposure to sulphur dioxide. [2]

Nitrogen oxides are associated with the reddish brown hue in vehicle exhausts. [1] Nitrogen oxides are toxic gases that cause significant inflammation of the airways and irritate the lungs. They lower resistance to respiratory infections such as flu. Continuous or frequent exposure to high levels of nitrogen oxides may cause increased incidence of acute respiratory disease in children. [2]

Ozone is a harmful gas that is the major component of photochemical smog. [1] Short-term exposure to ozone causes eye and lung irritation, including asthma attacks. [2] Longer-term exposure can cause chronic health problems. Ozone exposure is associated with reduced lung function and other lung diseases. [1] There is a relationship between air pollution and influenza, in that during flu season infection rates go up when ozone levels are high. [3]

Particulate matter is made up of various organic and inorganic substances, in the form of solid particles and liquid droplets in the air. It is the most obvious form of air pollution as it reduces visibility. The World Health Organisation currently believes there is no ‘safe’ level of particulate matter. Recent health studies have been unable to find a threshold below which particulate matter has no effect on health. The smaller or finer the particles are, the more hazardous they are for health as smaller particles are able to penetrate more deeply into the lungs. Particulate matter affects breathing and can aggravate existing respiratory and cardiovascular illnesses. Particulate matter also absorbs gaseous pollutants and delivers it directly to the lungs. It can alter the body’s defense against foreign materials, damage lung tissue and may also be carcinogenic. [2] Even short term exposure to high quantities of particulate matter is associated with a higher risk of death due to cardio-respiratory diseases. [1] Long term exposure is associated with reduced survival, the prevalence of bronchitis symptoms in children, and reduced lung function. [4]

Carbon monoxide interferes with the oxygen-carrying capacity of blood. [2]

Lead accumulates in the blood, bone and soft tissues. It is not readily excreted from the body and can affect the blood, kidneys, liver and nervous system. [2]

See Also

  1. Health effects of air pollutants


  1. 1.0 1.1 1.2 1.3 1.4 FAQ, Hedley Index - last accessed 9/8/10
  2. 2.0 2.1 2.2 2.3 2.4 2.5 The air that we breathe, CLSA, April 2005 - last accessed 7/8/10
  3. Experts symposium on air quality, Experts Symposium, THE AIR WE BREATHE: a public health dialogue, 9 January 2009 - last accessed 9/8/10
  4. Boomtown to gloomtown – The implications of inaction, CLSA, Christine Loh, James Paterson, September 2006 - last accessed 5/8/10