The city's roads have seen a significant change over recent years. Gone are the days of thick fumes and exhaust emissions blanketing central London. In their place, cleaner air and fewer pollutants – thanks in part to the introduction of the Ultra Low Emission Zone (Ulez). But just how much of an impact has this made on the health of Londoners? New research from Imperial College London suggests a notable correlation between the reduction in air pollution and a decrease in emergency hospital admissions.
When the T-charge was first introduced in 2017, followed by Ulez in 2019, central London residents were seeing an annual increase of 3% in emergency hospital admissions. But this trend reversed following the introduction of these initiatives. In fact, admissions decreased by 3% per year, with a significant reduction in heart problems (down 8%) and breathing difficulties (down 6%) among adults.
The T-charge, which targeted older, more polluting vehicles, was instrumental in encouraging drivers to upgrade their vehicles before the stricter Ulez regulations came into effect. Researchers at Imperial College London, led by Dr Daniela Fecht, meticulously controlled for external factors to ensure that the impact of Ulez and the T-charge could be isolated.
By comparing admission trends in central London with those in other comparable areas across England, the researchers were able to establish a link between the pollution reduction schemes and the observed health improvements. While the decrease in heart problem admissions remained statistically robust when compared with other areas, the downward trend for breathing difficulties – although present – did not reach statistical significance in the adult-only analysis.
Dr Rosemary Chamberlain noted that analysing data from children could provide more conclusive results regarding breathing problems. Additionally, the study acknowledged that while nitrogen dioxide levels decreased by approximately 44% before lockdowns due to the Covid-19 pandemic, the available health data was insufficient to fully differentiate between the effects of Ulez and those of lockdowns.
Dr Fecht pointed out that controlling for other variables allowed the researchers to confidently link the reductions in hospital admissions to the emission reduction initiatives. She suggested that while factors like increased walking or cycling might contribute, the primary cause of improved health is the reduction in air pollution – providing clear evidence of the public health benefits of clean air zones.