Air pollution is a mixture of particles and gases in the air that can damage our health. It is invisible and you cannot see or smell it. The most important air pollutants are particulate matter (PM) and nitrogen dioxide (NO2).
This is made up of lots of different sorts of things, including vehicle exhausts, smoke or soot from fires, bits of metal from engines, bits worn from brakes and tyres and dust and waste from the road. Particles can also be formed from chemical reactions in the air.
Particulate matter causes the most damage to health. When we breathe in, the larger particles stick in our throat and windpipe. The smallest particles go deep down into our lungs and can pass into our blood. Once in the blood, they can be transported around the body and they can be found in different organs.
Most of the particulate matter in the city, especially close to roads, comes from traffic. Burning wood and coal in domestic fires can also produce high levels of particulates. Particles can also be emitted to the air from industry and agriculture.
The gas, nitrogen dioxide, is another type of air pollutant that can affect our health. This is released into the atmosphere when fuels are burned and diesel cars and vans are the largest source.
How does air pollution affect our health?
Poor air quality affects everyone. The diagrams below show how air pollution can affect our bodies. It is linked to heart disease and worsens breathing problems.
Air pollution has the greatest impact on children, the elderly and people with existing heart and lung conditions. It can increase the risk of needing to be admitted to hospital with heart and lung conditions and contributes to people dying young – before their time.
Children are particularly vulnerable as their lungs are still developing. For their size, they breathe more air per minute than an adult – and buggies and prams put them at the level of car exhausts! Air pollution can stunt lung development, and can affect children for life.