Ground-level (tropospheric) ozone (O3) exists at a natural background level but is also produced when nitrogen oxides (NOx) and volatile organic compounds from vehicle emissions, petrol fumes, industrial processes solvents, and other human-made sources react in the presence of heat and sunlight. It is the primary component of photochemical smog. Ozone also occurs naturally in the stratosphere, where it protects us from ultraviolet radiation – this ozone occasionally can mix downwards to ground level.
Ozone is a colourless, odourless gas. Exposure to high concentrations of ozone can cause respiratory health problems and is linked to cardiovascular health problems and increased mortality. Those most at risk include people with asthma, children, older adults, and people who are active outdoors, such as outdoor workers. People with certain genetic characteristics and nutrient deficiencies are also at greater risk from ozone exposure. Ozone can also affect sensitive vegetation and ecosystems and can cause damage during the growing season.
This dataset reports on the seasonal trends assessed for the period 2011-2020.
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.
