Fact-check · 2026-06-12

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/factcheck Skip to main contentSkip to navigation Thank you Your support powers our independent journalism Print subscriptions Search jobs My account UK The Guardian - Back to homeThe Guardian News Opinion Sport Culture Lifestyle Show more Environment Climate crisis Wildlife Energy Pollution Traffic on A12 road with City of London skyscrapers in the background. View image in fullscreen London’s ultra low emissions zone was introduced in 2019 and expanded in 2023. Photograph: Marcin Rogozinski/Alamy Pollutionwatch Air pollution Emergency hospital admissions fell after introduction of London’s T-charge and Ulez, study suggests Imperial College scientists analysed health records before and after introduction of air pollution reduction zones Gary Fuller Fri 12 Jun 2026 06.00 BST Share Prefer the Guardian on Google Low emission and clean air zones attract controversy whenever they are proposed, but there is growing evidence that they work in improving air quality. The Bradford zone was followed by a reduction of about 25% in GP visits for heart and breathing problems and survey data shows that the central London zone was followed by a reduction in the likelihood of a person taking sick leave. Now analysis of health records has found emergency admissions to hospital reduced after the introduction of the T-charge and ultra-low emissions zone (Ulez) in central London. Both schemes were designed to reduce air pollution inhaled by Londoners. Starting in 2017, the T-charge was an additional congestion charge for older, more polluting vehicles. During T-charge, many of the vehicles that drove in central London were upgraded in preparation for the introduction of the more comprehensive central London Ulez in 2019. Dr Rosemary Chamberlain, who undertook the research at Imperial College London, said: “Given what we know about the link between air pollution and health, we wanted to understand if the introduction of the T-charge and Ulez also resulted in a reduction in people being admitted to hospital.” The researchers looked at emergency admissions to hospital, excluding cases such as accidents, burns, drug overdose, poisoning or self-harm. For people living in the central London zone, admissions increased at 3% per year before the schemes started. After their launch there was decrease of 3% per year in emergency admissions, including an 8% reduction for heart problems and a 6% reduction for breathing problems. A wood-burning stove Labour must fulfil promise to introduce clean air act, charities urge Read more The researchers then investigated whether the changes could have been due to other factors. Chamberlain said: “We needed to make sure that we could separate the effect of the schemes from other trends, such as changes in healthcare seeking behaviour, overall trends in hospital admissions and other policies that improved air pollution. We did this by looking at other areas in the country that are similar to the central Ulez area.” People protest against Ulez. View image in fullscreen Ulez has faced opposition since its introduction. Photograph: Martin Pope/Zuma Press Wire/Rex/Shutterstock The reduction in the total emergency admissions and the decrease for heart problems remained robust when compared with other areas. The downward change for breathing problems was still present in the data, but this did not reach statistical significance. Chamberlain said: “The inconclusive finding for respiratory outcomes may be partly because our analysis considered adults only. Children are particularly susceptible to the effects of air pollution on respiratory health, so an analysis of childhood respiratory outcomes may show a more conclusive result.” The central London Ulez was launched just one year before the Covid pandemic. Although nitrogen dioxide from traffic had been reduced by about 44% on roads in central London before lockdowns began, the researchers did not have sufficient health data to distinguish between the separate effects of Ulez and T-charge. Dr Daniela Fecht, who led the study, said: “We controlled for other factors and trends in our study design so we can conclude that reductions in hospital admissions are directly linked to the emission reduction initiatives in central London. “Other factors such as more walking and cycling or a reduction in traffic noise may also be contributing but we are fairly certain that these improvements in health are due to the reductions in air pollution. Our results provide clear evidence that clean air zones and low emission zones can bring public health benefits.” Explore more on these topics Air pollution Pollutionwatch London Low emission zones Health NHS news Share Reuse this content Most viewed Starmer admits he must ‘turn things around’ as US adds to pressure over defence spending Live Elon Musk becomes world’s first trillionaire after SpaceX shares jump on stock market debut – business live Live Middle East crisis live: final text of peace deal between US and Iran agreed, says Pakistan’s prime minister Jemma Stapleton, Australian sprinter and Stawell Gift finalist, dies aged 25 on family holiday Labour’s woes are like a slow-motion car crash – and Keir Starmer isn’t even in the driving seat Marina Hyde Most viewed EnvironmentClimate crisisWildlifeEnergyPollution News Opinion Sport Culture Lifestyle Original reporting and incisive analysis, direct from the Guardian every morning Sign up for our email About us Help Complaints & corrections Contact us Tip us off SecureDrop Privacy policy Cookie policy Modern Slavery Act Tax strategy Terms & conditions All topics All writers Newsletters Digital newspaper archive Bluesky Facebook Instagram LinkedIn Threads TikTok YouTube Advertise with us Guardian Labs Search jobs Patrons Work with us Accessibility settings Back to top © 2026 Guardian News & Media Limited or its affiliated companies. 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