C15.05: Atmospheric pollutants

• Combustion of fuels is a major source of atmospheric pollutants
• Most fuels (including coal) contain carbon and/or hydrogen and may also contain some sulphur
• The gases released into the atmosphere when a fuel burns may include carbon dioxide, water (vapour), carbon monoxide and oxides of nitrogen (which are formed at high temperatures)
• Solid particles and unburned hydrocarbons may be released during the combustion of fuels, forming particulates in the atmosphere.
• If there is not enough oxygen, some of the fuel does not burn - this is incomplete combustion. Here, solid particles of soot (carbon), carbon monoxide and unburnt fuel are released in the air.
• The combustion of hydrocarbons releases energy. During combustion, the carbon and hydrogen in the fuels are oxidised to form carbon dioxide and water.
• Carbon monoxide is a toxic gas which is colourless and odourless so not easy to detect. It takes the place of oxygen in red blood cells by binding to haemoglobin which leads to oxygen deprivation.
• Sulphur dioxide and oxides of nitrogen cause acid rain and respiratory problems in humans.
• Particulates cause global dimming and human health problems