Air pollution is made up of gases or particles which are harmful to humans and other life. The health impact is bigger the higher the concentration and the greater the exposure. For some pollutants there is no safe limit and exposure to even fairly low concentrations is harmful.
Nitrogen oxide and nitrogen dioxide
Exhaust fumes from vehicles contain a group of gases called nitrogen oxides. These include nitrogen dioxide, a harmful gas produced by burning petrol and diesel.
Spending time in areas with high levels of air pollution can worsen asthma symptoms, damage lungs and harm cardiovascular health. Nitrogen oxides also damage the environment and affect biodiversity in sensitive habitats.
The UK and EU have legal limits on concentrations of nitrogen dioxide. These limits are currently breached in Bristol. 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.
Due to the small size of many of the particles, these toxins can enter the bloodstream and are transported around the body, lodging in the heart, brain and other organs.
Exposure to particulate matter can result in serious health impacts, especially in vulnerable people such as the young, elderly, and those with respiratory problems.