Air pollution is made up of gases or particles which are harmful to humans and other life.
For some pollutants there is no safe limit and exposure to even fairly low concentrations is harmful.
Nitrogen oxide and nitrogen dioxide
Exhaust fumes contain gases called nitrogen oxides. These include nitrogen dioxide, a harmful gas produced by burning petrol and diesel. Nitrogen dioxide irritates the airways of our lungs and affects the way they work.
The UK and EU have legal limits on concentrations of nitrogen dioxide. The Clean Air Zone will help us reduce nitrogen dioxides to legal limits by 2023.
Particulate matter is everything in the air that is not a gas. It’s made up of partially burned fuel and engine oils, tiny specks from worn tyres, brake discs and road dust.
The small size of the particles means they can enter the bloodstream and affect the heart, brain and other organs.
Particulate matter can have a serious impact on our health, especially vulnerable people such as the young, elderly and those with breathing problems.