Despite recent improvements in air quality, toxic air pollution remains the biggest environmental risk to the health of all Londoners. Around half of London’s NOx emissions are from road transport. Reducing the amount of pollution from traffic remains one of the best ways of cleaning up air in London.
Around 4,000 Londoners died prematurely in 2019 because of long-term exposure to air pollution. It is a cause of cancer and increases the risk of asthma, stroke and dementia. Pollution is also stunting the growth of children’s lungs in ways that will affect them for the rest of their lives.
The purpose of the Ultra Low Emission Zone (ULEZ), introduced in April 2019, is to improve air quality in and around central London by reducing the number of older more polluting vehicles that enter the central zone. This will reduce the amount of NOx emitted, which in turn will reduce nitrogen dioxide (NO2) concentrations in the zone. Bringing London closer to compliance with the legal air quality limit values for NO2 is a key aim of the scheme.
In October 2021, the ULEZ was expanded to a much larger area of London, out to the North and South Circular roads, an area 18 times the size of the original central zone and home to 3.8 million people. With this expansion along with other measures implemented by the Mayor, London expects to meet legal limits for NO2 by 2025.