Air Quality C1

The atmosphere contains:

• 78% Nitrogen
• 21% Oxygen
• 1% Argon and other noble gases
• Small amounts of water vapour, carbon diocide and other gases

There are 4 stages to the evolution of the earth's atmosphere:

1. Volcanic activity created carbon dioxide and water vapour
2. The earth cooled and the water vapour condensed forming oceans
3. Simple photosynthetic organisms evolved in oceans creating oxygen to the atmosphere and removing carbon dioxide
4. Carbon dioxide removed by it dissolving in oceans forming sedimentary rocks and fossil fuels

Humans create pollutants by burning fossil fuels in car engines and power stations. This can lead to acid rain making rivers to acidic for organisms to survive, affecting food chains and natural resources.

• Carbon dioxide is harmful to the environment because it traps heat in the atmosphere (greenhouse gas)
• Nitrogen oxide is harmful to the environment and humans because it causes acid rain and causes breathing problems e.g. asthma
• Sulfur dioxide is harmful to the environment because it causes acid rain
• Particulates (small particles of solids e.g. carbon) are harmful to the environment and humans because they make buildings dirty and they cause asthma and lung infections
• Carbon monoxide is dangerous to humans because it can prevent blood from circulated oxygen around the body, causing death in some cases

Concentrations of pollutants in the air are measured in ppb (parts per billion) or ppm (parts per million) e.g. a sulfur dioxide concentration of 16ppb means that there are 16 molecules of sulfur dioxide in 1 billion molecules of air

When measuring concentrations you must repeat measurements because, for example, nitrogen oxide in the air may change depending on the time of day, because of the amount of traffic and the weather. These repeated measurements are then calculated to make the mean, giving a true value of the concentration of the pollutant

Each element contains tiny particles called atoms. Atoms can then join together to create molecules

Compounds are created when…