In April 2019, the Ultra Low Emission Zone (ULEZ) was introduced in central London with the aim of improving London's air quality by reducing traffic in the city – tackling the harmful effects of air pollution on health and the impact of climate change.
How ULEZ tackles the harmful effects of air pollution
In London, toxic air contributes to around 4,000 premature deaths each year, as well as increased risks of asthma and cancer. Vehicle emissions contribute to almost half of London's air pollution. Under ULEZ, vehicles must meet its emissions standards or pay a £12.50 daily charge to drive within the zone. ULEZ operates 24 hours a day, seven days a week and on every day of the year except Christmas.
Find out how Queen Mary research into the impact of air pollution on children's lung development helped to introduce ULEZ.
How ULEZ is changing the school run
Much of the research on ULEZ focuses on the impact of the intervention on pollution levels and health- this includes Queen Mary's long-running Children's Health in London and Luton (CHILL) study, which is looking at the impact of ULEZ on children's health.
There's little research on the effectiveness of other public health interventions that have been promoted alongside ULEZ, such as active commuting. An earlier study from the CHILL group found that 42% of children who travelled by car switched to active travel modes after the ULEZ was introduced, but researchers wanted to take a deeper look at the impact of ULEZ on active travel to school – what are the key drivers of change and ongoing challenges. The researchers focused on the experiences of people most vulnerable to effects of air quality.
In the research published today in BMJ Open — led by scientists from the University of Cambridge and Queen Mary University of London — families reported the rising costs of car travel and reduced convenience made active travel more appealing. Those who already walked or cycled discussed how improved air quality made the journey more enjoyable and healthier.
With less traffic, some families took longer scenic routes home, which meant they spent more time together being active. Teachers observed fewer asthma related symptoms among students and noted that safer streets encouraged more outdoor play.
Dr Olivia Alliott, lead author from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge, said: "Policies like the ULEZ play a crucial role in promoting a healthier school journey for many families. However, a fundamental part of their success is making sure that everyone experiences these benefits by ensuring such policies are implemented alongside accessible and affordable alternatives to driving.
"Our previous work found that the ULEZ has encouraged children to take up walking and cycling to school. This work identifies some of the possible reasons for that, and highlights both the positive and negative experiences of the ULEZ which are reflected in an individual's ability to pay the charge and the alternative travel modes available"
Joint senior author Professor Chris Griffiths from the Wolfson Institute of Population Health, Queen Mary University of London, said: "This important study brings yet another perspective telling us how the ULEZ can affect the way families can live, travel and experience the environment. These systemic effects on society go beyond simply 'cleaning the city air'"
ULEZ and active travel: the positives
People who already walked or cycled on the school run before the implementation of ULEZ reported that improved air quality made their journey more enjoyable. With less traffic, some families took longer and more scenic routes home, which meant they spent more time together being active.
Teachers also observed fewer asthma-related symptoms and noted that because there were less cars on the road.
