Deaths linked to air pollution in London fell by an estimated 40% over the five years from 2019, according to new analysis from Imperial College London. The study also found that toxic air pollution levels dropped sharply, with nitrogen dioxide down 41% and fine particulate matter down 28%.
Revised health impact estimates
The researchers updated previous estimates, which attributed 4,000 premature deaths in 2019 to air pollution, to a range of 6,400 to 8,000. For 2024, the figure is estimated at 3,800 to 5,100 premature deaths. Dr David Dajnak from the Imperial Environmental Research Group said: “Our study highlights two key findings: London’s air quality has improved markedly since 2019, but despite this progress, air pollution remains a serious public health risk.”
Ulez expansion credited
London Mayor Sadiq Khan welcomed the findings as “overwhelming evidence” that his ultra-low emission zone (Ulez) was saving lives. While the Imperial report did not single out any specific policy, Khan stated: “The evidence is now overwhelming and unarguable: the bold action we have taken in London has reduced pollution, improved public health and saved lives. This latest data shows why expanding Ulez London-wide was even more important than we previously thought and is transforming lives right across our capital.”
The Ulez was launched in 2019 in central London and expanded to inner boroughs in 2021, then to all of London in 2023. Vehicles not meeting emission standards—typically diesel cars from before 2015 or petrol cars from before 2004—must pay a daily charge of £12.50. Currently, about 97% of vehicles driving in the zone are compliant.
Outer London boroughs most affected
The research found that in 2024, boroughs with the highest ratio of deaths attributable to air pollution were in outer London, including Bexley, Havering and Sutton. City Hall said this underlined the significance of expanding the Ulez to the entire capital despite widespread local opposition.
A separate study last year for the Greater London Authority showed that roadside NO2 pollution was 27% lower than expected without the Ulez.
Additional measures and reactions
Beyond Ulez, Khan’s administration has provided £2.7 million for indoor air quality filters in 200 primary schools and increased the number of zero-emission buses in Transport for London’s fleet from 30 to over 3,000 in the last decade. Khan is due to visit a primary school in east London on Wednesday, echoing a visit he made in 2016 when he pledged to speed up air quality policies.
Prof Stephen Holgate, special adviser on air quality at the Royal College of Physicians, called the scale of improvement “so encouraging” and “a powerful reminder that decisive, sustained action can deliver real, measurable benefits for people’s health.” Jemima Hartshorn of Mums for Lungs said the research showed Ulez helped clean the air, but added: “Over 100,000 children went to hospital with breathing issues in London in 2024. And other cities and regions are still more polluted. Londoners need more action, and so does the rest of the country.”
