Asthma UK Centre for Applied Research

Project: CHILL Cognition

Children’s Health in London and Luton (CHILL): impact of London’s Ultra Low Emission Zone on brain development in schoolchildren

The CHILL study is investigating the impact of the new London Ultra Low Emission Zone (ULEZ) on the respiratory and cognitive health of children attending school within the Ultra Low Emissions Zone.


Do reductions in diesel tailpipe emissions, delivered through the implementation of the ULEZ, lead to improvements in children’s mental development and health?


Our plan of investigation is to ask the 3,416 primary school children taking part in our 4 year cohort study (the CHILL study) to undergo additional assessments of cognitive development (fun tasks on tablet computers) and additional mental health (validated questionnaires) over the next 3 years.

We are already measuring effects of air pollution on respiratory health and lung development in 3,416 primary school aged children. This study will run between 2018-2023 (4 academic school years), straddling the introduction (April 2019) and city-wide expansion (planned for Oct 2020) of London’s ULEZ. During the second year of the CHILL study 2018/19 we added cognitive testing to the study, with support from the Born in Bradford study team; we now wish the extend this analysis to the final two years of the study, together with additional assessments of children’s overall mental well-being.


The CHILL project (which is running between 2018-2023) will be visiting primary schools to investigate the impact of the ULEZ zone on children's health. On school visits, children will take part in computer based games testing cognitive development and spriometry to assess the impact of the ULEZ zone on their lungs.

  • cognitive function (annually, at school visits)
  • mental health
  • RCADS questionnaire annually, by child at cognitive assessment session
  • SDQ Strengths and Difficulties Questionnaire, annually by teacher
  • CHU9D completed annually, by parent by post
  • Coded NHS health record data on mental health and behavioural outcomes

Visit the CHILL study website

Key People

Headshot of Chris Griffiths

Chris Griffiths

Ian Mudway

Ian Mudway

Centre Director,

Lead: Preventing asthma attacks

Principle Investigator
Based at: Queen Mary University, London Imperial College London
Chris' Profile CHILL Team page
Mark Mon-Williams

Mark Mon-Williams

headshot of James Scales

James Scales

Principle Investigator Postdoctoral Researcher
Based at: University of Leeds Based at: Queen Mary University, London
CHILL Team page CHILL Team page
Rosamund Dove

Rosamund Dove

Jasmine Chavda

Postdoctoral Researcher Researcher
Based at: Queen Mary University, London Based at: University of Bedfordshire
CHILL Team page CHILL Team page
headshot of Iva Tsocheva

Iva Tsocheva

Postdoctoral Researcher
Based at: Queen Mary University, London
CHILL Team page


2018-2023 (academic school year)

Contact Us

For updates on the project and related news, follow us on Twitter @CHILLpollution

If you want to contact the study team directly email us on or


We are funded research funded by Barts Charity and the Mayor of London. The views expressed are those of the authors and not necessarily those of the NHS, or the Department of Health

The National Institute for Health Research, The North Thames ARC and the Medical Research Council has provided extra funding for elements of the study.