Pollutants from fuels

• When do fuels release energy?

  When they are combusted, two examples of fuels are coal and hydrocarbons. Coal is used to generate electricity in power stations, Hydrocarbons such as those found in petrol and diesel are used to power vehicles.
• What do most fuels contain?

  Carbon and hydrogen, when we burn fuels, carbon and hydrogen atoms react with oxygen in the air (these elements are oxidised).
• What is complete combustion?

  When carbon is reacted to make carbon dioxide and the hydrogen atoms have been oxidised to form water vapour.
• What do we need lots of for complete combustion?

  Oxygen, if the amount of oxygen is reduced then we make carbon monoxide, this is a toxic gas and it has no colour or smell. Because of this, many people have carbon monoxide detectors in their home.
• What do some fuels contain?

  Some fuels e.g. coal contain the element sulfur, when coal is burned, the sulfur atoms are oxidised. This produces sulfur dioxide.
• Where are oxides of nitrogen produced?

  Inside engines e.g. cars, here high temperatures cause nitrogen and oxygen in the air to react. This produces a range of different molecules which we call oxides of nitrogen.
• What problems do sulfur dioxide and oxides of nitrogen cause?

  Breathing problems in humans, they dissolve in rainwater to form acid rain which can damage trees and corrode buildings made from limestone.
• What is particulate pollution?

  Particles of carbon and unburned hydrocarbons, these damage human health and increase the risk of heart disease and lung disease. They also reduce the amount of energy from the sun that reaches the Earth's surface, this is called global dimming. Global dimming affects rain patterns.