The expansion of London’s ultra-low emission zone (Ulez) has led to a significant drop in air pollution levels, as revealed in a recent study. This decrease in harmful pollutants is linked to a wide range of health benefits, including reduced cancer risks, improved lung development, lower chances of heart attacks, and fewer premature births. The most noticeable improvements were observed in the city’s most deprived areas.

The decision to extend Ulez to outer London boroughs encountered strong resistance, with some councils attempting legal challenges and the Labour party attributing their defeat in a by-election to the policy. However, a report published by the Greater London Authority and reviewed by an independent group of experts has confirmed the positive impact of the Ulez expansion on the capital’s air quality.

Notably, London’s air is now improving at a faster rate than the rest of England, with pollution levels in outer parts of the city experiencing significant improvements and now comparable to the national average. The study also highlights the substantial reduction in greenhouse gases, equating to the carbon dioxide emissions of nearly 3 million one-way trips from Heathrow to New York being saved.

Maria Neira, the director of environment, climate change, and health at the World Health Organization, has commended London’s efforts, stating that initiatives like Ulez are crucial for public health and contribute to a healthier and more sustainable urban environment.

The detailed findings include a 27% decrease in roadside nitrogen dioxide levels since Ulez was introduced in 2019 and a 31% reduction in small-particle emissions from vehicle exhausts in outer London this year compared to what would have been without the expansion. Additionally, air quality has improved across 99% of monitoring sites in the city since 2019.

The Ulez scheme, originally launched in the city center in 2019 and expanded to cover the entire capital in August 2023, imposes a £12.50 daily charge on the most polluting vehicles driven within the zone. However, the majority of vehicles are compliant and do not face any charges. About 4,000 premature deaths a year in London have been linked to air pollution, which is known to affect every organ in the body and increase the risk of numerous health issues.

Source: https://www.theguardian.com/environment/2025/mar/07/london-air-pollution-down-since-ulez-expansion-study