Emergency hospital admissions decreased following the introduction of London's T-charge and ultra-low emissions zone (Ulez), according to a new study by Imperial College London. The research adds to growing evidence that low emission and clean air zones effectively improve air quality and public health.
Study Details
Scientists analyzed health records before and after the implementation of the T-charge in 2017 and the central London Ulez in 2019. Both schemes aimed to reduce air pollution from vehicles. The T-charge imposed an additional fee on older, more polluting vehicles driving in central London, prompting many upgrades before the stricter Ulez took effect.
Dr. Rosemary Chamberlain, who led the research at Imperial College London, stated: "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."
Key Findings
The study examined emergency hospital admissions, excluding cases like accidents, burns, drug overdoses, poisoning, or self-harm. For residents of the central London zone, admissions were increasing at 3% per year before the schemes began. After their launch, emergency admissions decreased by 3% annually, including an 8% reduction for heart problems and a 6% reduction for breathing problems.
To ensure the changes were not due to other factors, the researchers compared London's data with similar areas in the country that did not implement such schemes. The reduction in total emergency admissions and heart-related admissions remained statistically significant. However, the decline in respiratory admissions did not reach statistical significance.
Chamberlain noted: "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."
Broader Context
The central London Ulez was launched just a year before the COVID-19 pandemic. Although nitrogen dioxide from traffic had already decreased by about 44% on central London roads before lockdowns, the researchers lacked 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."
Previous Evidence
Low emission and clean air zones have often faced controversy, but evidence of their effectiveness continues to mount. For instance, the Bradford clean air zone was followed by a roughly 25% reduction in GP visits for heart and breathing problems. Survey data also showed that the central London zone led to a decrease in sick leave among residents.
