Study: London ULEZ Rapidly Cleaning up Air Pollution

Expanding the city’s ultra low-emission zone has resulted in dramatic drops in particle emissions in inner and outer London.

1 minute read

March 10, 2025, 9:00 AM PDT

By Diana Ionescu @aworkoffiction


Close-up of green ULEZ sign in London, UK.

tktktk / Adobe Stock

London’s ultra low emission zone (ULEZ) is resulting in cleaner air in all parts of the city, according to a report from London City Hall reviewed by independent experts.

An article in Smart Cities World explains that the study shows reduced particle emissions, with the biggest reductions in central London (54 percent) and a 24 percent reduction in outer London, in the ULEZ expansion zone.

“Thanks to all phases of the Ulez, NOx emissions from road transport are estimated to be 36 per cent lower across London in 2024, a saving of around 3400 tonnes – the equivalent of approximately one year of emissions from all passenger car trips in Los Angeles.” The reductions are speeding up a process that was expected to take up to 200 years; instead, London could reach its air pollution cleanup goals this year.

The ULEZ has not reduced business or foot traffic — in fact, foot traffic increased by almost 2 percent in outer London. The report also shows that Londoners are quickly switching to cleaner, ULEZ-compliant vehicles. London vans are now 90.7 percent compliant. “In February 2017, just 12 per cent of vans met the Ulez standards, demonstrating the schemes’ impact on reducing the number of more polluting older vans driving in London.”

Monday, March 10, 2025 in Smart Cities World

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