Ozone is a colourless, toxic gas. At ground level, it is formed from nitrogen oxides and other volatile organic compounds by solar radiation, through photochemical processes.
- Main sources: road traffic, combustion plants, solvents, agriculture
- Health effects: damage to the lungs, intensification of asthma symptoms or other lung diseases, irritation of the respiratory tract
- Affected risk groups: people with lung diseases, children, seniors, people active outdoors
- Environmental impact: impaired plant growth, quality and quantity of agricultural products