Bitesize has changed! We're updating subjects as fast as we can. Visit our new site to find Bitesize guides and clips - and tell us what you think!


Chemical reactions and pollutants

Burning fuels

Burning fuels releases harmful pollutants into the air. Pollutants can kill plants, harm our lungs, cause acid rain [acid rain: Rain that contains a high level of acids. It is believed to be caused by pollution and, maybe, natural activity such as volcanic eruptions. ] and are thought to contribute to global warming.

Photograph of coal burning

We burn fuels such as coal to produce energy.

A combustion reaction is when a chemical reacts with oxygen and releases energy.

We burn fuels to produce energy. When these fuels burn, the atoms [atoms: An atom is the smallest part of an element that still has the properties of that element, comprising electrons surrounding a nucleus of protons and neutrons. ] in the fuels combine with oxygen from the air to make new moleculesmolecules: a collection of two or more atoms held together by chemical bonds. The fundamental unit of compounds.

Coal is made mainly of carbon. This burns to produce carbon dioxide.

Petrol, diesel fuel and fuel oil are hydrocarbons. Their molecules are made of carbon and hydrogen atoms. When these fuels burn, the carbon and hydrogen atoms combine with oxygen atoms to produce carbon dioxide and water vapour.

Back to Air quality index

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.