Impact of London’s Ultra Low Emission Zone on children’s health and costs: evidence from NHS health records

Air pollution from traffic harms children’s health and development, stunting lung growth and damaging brain development. Clean air zones and London’s Ultra Low Emission Zones (ULEZ) are being implemented to improve air quality, but they are costly to implement and their impacts on health are not known. We urgently need research to determine the health impacts of these zones to guide health policy.

The London ULEZ was introduced in 2019, covering initially only Central London, and since has been extended with the most recent expansion to span all Greater London. In 2018, we set up the CHILL (Children’s Health in London and Luton) study to find out whether improved air quality arising from London’s ULEZ improves lung growth and development in children. We recruited 3,400 children from 41 primary schools in London, and 44 in Luton to compare the health of children in London (breathing cleaner air due to the ULEZ) with those in Luton.

The CHILL study design is co-created through extensive and ongoing consultation with parents, primary schoolchildren, teachers, community action groups, and lived experience experts with asthma from the Asthma UK Centre for Applied Research Patient and Public Involvement Group.

This ‘natural experiment’ offers a unique opportunity to trace children’s development alongside changes in air quality and provide the most robust evidence on health impacts of breathing clean air.

In this research proposal, we now propose to determine additional impacts of the ULEZ on children’s health by examining the data held in NHS health records of the children taking part in the CHILL study.

We have NHS ethical approval and have been seeking consent from CHILL children and their parents to access their health records. For those consenting, we will approach their GP practices to request electronic copies of their records. All healthcare record data will be held securely and confidentially under the strictest approved protocols. We will check the health records for new diagnoses of respiratory, allergy, developmental, and mental health conditions, respiratory infections, COVID-19, and healthcare use.

For example, we will test if the number of asthma attacks has fallen for children in London, compared with those in Luton. We will also test if fewer children are being diagnosed with asthma, chest infections and allergies.

This work will provide a powerful and detailed assessment of the impacts of a major city-wide low-emission zone on children's health and development.

Findings from this study will improve our understanding of how cutting traffic pollution affects the health, wellbeing, and healthcare use of children in London. These results will help inform strategies to improve air quality across the UK and globally. We will share our results internationally with clinicians, policymakers, educators, and the public to influence policy and practice.

Amount awarded £49, 891