New analysis from researchers at Imperial College London suggests that policies aimed at reducing vehicle emissions in central London are associated with measurable improvements in public health, particularly through reductions in emergency hospital admissions for cardiovascular and other conditions.
The study examined the impact of the Ultra Low Emissions Zone (ULEZ) and its predecessor, the toxicity charge (T-Charge), both introduced to discourage the use of the most polluting vehicles in central London. The T-Charge began in 2017, followed by ULEZ in 2019, which introduced a daily charge for vehicles that do not meet strict emissions standards. While earlier evidence has shown improvements in air quality and increases in cleaner vehicles, the health impacts have been less well established.
Researchers analysed hospital admission data from January 2014 to March 2020, comparing periods before and after the introduction of the schemes. The study ended before the COVID-19 pandemic to avoid distortion from major changes in travel behaviour and pollution levels. The analysis focused on emergency admissions among adults for cardiovascular disease, respiratory disease, and all causes, conditions known to be sensitive to short-term exposure to air pollution. A comparison area in outer London was included to account for wider trends unrelated to the policy.
The findings show that the introduction of the T-Charge and ULEZ was associated with an 8.1% reduction in yearly trends for cardiovascular admissions, a 6.2% reduction for respiratory disease, and a 3.1% reduction in all-cause admissions within the intervention area. After adjusting for trends in the control area, the reductions remained significant for cardiovascular disease at 9.3% and for all-cause admissions at 5.1%. The respiratory results became inconclusive, showing a 2.7% reduction that was not statistically significant.
Researchers from Imperial College London emphasised that the strongest evidence of benefit was seen for cardiovascular outcomes, suggesting that reductions in air pollution may lead to relatively rapid improvements in heart health and fewer emergency hospital visits. However, Dr. Rosemary Chamberlain, Honorary Research Associate within Imperial’s School of Public Health, cautioned that respiratory results should be interpreted carefully, as results were “inconclusive”, and furthermore, many respiratory conditions are managed in primary care rather than hospitals, which may not be captured in the data.
Additionally, the authors highlighted several limitations, including the restricted study period and the exclusion of the COVID-19 era due to its significant impact on traffic and pollution patterns. They also stressed the need for further research, particularly into the effects on children, who are more vulnerable to air pollution exposure.
To conclude, the findings add to the growing evidence that low-emission transport policies may improve population health while also reducing pressure on hospital emergency services.
Funding was provided by the Medical Research Council, the MRC Centre for Environment and Health, the NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, the NIHR Imperial Biomedical Research Centre, and the Imperial College Healthcare NHS Trust.
To read the full article from Imperial College London, please see: London’s ULEZ and T-charge linked to reductions in emergency hospital admissions | Imperial News | Imperial College London
Image: Matt Brown, Wikimedia Commons