Children exposed to diesel-dominated air pollution in London are showing poor lung capacity, putting them at risk of lifelong breathing disorders, according to a study led by Queen Mary University of London, King's College London and the University of Edinburgh.
The research, published in The Lancet Public Health journal, shows that whilst traffic pollution control measures have improved air quality in London, they still need significant strengthening to protect children's health.
Air pollution is a leading cause of global mortality, with the World Health Organization estimating over four million deaths annually caused by outdoor air pollution. Children are especially vulnerable and at risk of lifelong breathing disorders, asthma attacks, chest infections and earlier death.
Professor Chris Griffiths from Queen Mary University of London said: "Despite air quality improvements in London, this study shows that diesel-dominated air pollution in cities is damaging lung development in children, putting them at risk of lung disease in adult life and early death.
"We are raising a generation of children reaching adulthood with stunted lung capacity. This reflects a car industry that has deceived the consumer and central government which continues to fail to act decisively to ensure towns and cities cut traffic."
Low Emission Zones (LEZ) restrict or penalise vehicle entry into urban areas to encourage the uptake of lower emission technologies. London introduced the world's largest city-wide LEZ in 2008, roughly contiguous with the M25 orbital motorway and encompassing around 8.5 million residents. But up until now, there has been little evidence on whether LEZs improve air quality or public health.
2,164 children aged 8-9 were enrolled into the study from 28 primary schools in the London boroughs of Tower Hamlets, Hackney, Greenwich and the City of London (all areas which fail to meet current EU nitrogen dioxide limits). The research team monitored children's health and exposure to air pollutants over five years, covering the period when the LEZ was introduced, and found:
- Children exposed to air pollution showed significantly smaller lung volume (a loss of approximately 5 per cent in lung capacity). This was linked to annual exposures of nitrogen dioxide (NO2) and other nitrogen oxides (NOx), both of which are in diesel emissions, and particulate matter (PM10).
- Following the implementation of London's LEZ, there were small improvements in NO2 and NOx levels, but no improvements in PM10 levels.
- Despite these improvements in air quality, there was no evidence of a reduction in the proportion of children with small lungs or asthma symptoms over this period.
- The percentage of children living at addresses exceeding the EU limit for NO2 fell following the LEZ introduction, from 99 per cent in 2009 to 34 per cent in 2013, but they were exposed to higher levels when at school, many of which were next to busy roads.
- Significant areas of inner and outer London still remain above the EU NO2 limits.
The researchers warn that, at the current rate of change of pollution levels, full compliance with EU limits for NO2 for London remains distant, unless there is significant tightening of current emission controls.
In the meantime, they say clinicians should consider advising parents of children with significant lung disease to avoid living in high pollution areas, or to limit their exposures.
Dr Ian Mudway from King's College London said: "There is an urgent need to improve our air quality, especially within our congested cities. Policies such as the Low Emission Zone strive to do this, but their effectiveness needs careful and objective evaluation, not only in terms of whether they improve air quality, but more importantly, whether they deliver better health. As the evidence base grows demonstrating that air pollution impacts on the health of children born and growing up in our cities, so the justification for decisive action increases."
Dr Samantha Walker, Director of Research and Policy at Asthma UK, said: "It is disappointing that the Low Emission Zone in London has not helped to improve children's lung capacity and shows that a piecemeal approach to reducing air pollution does not work. If children's lungs don't develop properly as a result of air pollution it can increase their likelihood of developing asthma, leaving them coughing, wheezing and at risk of a life-threatening asthma attack. The Government needs to tackle toxic air by putting in place a new Clean Air Act to keep everyone, especially children, safe."
Professor Frank Kelly from NIHR Health Impact of Environmental Hazards HPRU said: "These new findings linking air pollution and children's lung growth provide further support for the introduction of the ultra Low Emission Zone in London early next year."
The study is a collaboration across the MRC Asthma UK Centre in Allergic Mechanisms of Asthma, the Asthma UK Centre for Applied Research and the MRC-PHE Centre for Environment and Health, and was funded by NHS Hackney, the NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London with donations from Him Lee and the Felicity Wilde Charitable Trust.
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Notes to the editor
* Research paper: 'Impact of London's Low Emission Zone on air quality and children's respiratory health' by Ian S. Mudway, Isobel Dundas, Helen E. Wood, Nadine Marlin, Jeenath B. Jamaludin, Stephen A. Bremner, Louise Cross, Andrew Grieve, Alex Nanzer, Ben M. Barratt, Sean Beevers, David Dajnak, Gary W. Fuller, Anna Font, Aziz Sheikh, Robert Walton, Jonathan Grigg, Frank J. Kelly, Tak Lee, Chris J Griffiths. Lancet Public Health. DOI: 10.1016/S2468-2667(18)30202-0
Available here after the embargo lifts: http://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30202-0/fulltext
About Queen Mary University of London
Queen Mary University of London is a world-leading research-intensive university with over 25,000 students representing more than 160 nationalities.
A member of the prestigious Russell Group, we work across the humanities and social sciences, medicine and dentistry, and science and engineering, with inspirational teaching directly informed by our research.
In the most recent exercise that rated research in the UK, we were ranked 5th in the country for the proportion of research outputs that were world-leading or internationally excellent. We offer more than 240 degree programmes and our reputation for excellent teaching was rewarded with a silver in the 2017 Teaching Excellence Framework (TEF) awards.
Queen Mary's history dates back to 1785, with the foundation of the London Hospital Medical College. Our history also encompasses the establishment of the People's Palace in 1887, which brought accessible education, culture and recreation to the East End of London. We also have roots in Westfield College, one of the first colleges to provide higher education to women.
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The National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at Guy's and St Thomas' NHS Foundation Trust and King's College London works to develop and deliver new medicines and diagnostics to patients, drive research and innovation into the NHS, and provide national systems leadership for maximum impact to patients.
With our research activity organised into nine themes, each holding an individual Athena Swan Silver award highlighting our commitment to equality and diversity, and supported by our interdisciplinary, world leading infrastructure, we are poised to deliver the next step change for the health and wealth of our nation.
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King's College London is one of the top 10 UK universities in the world (QS World University Rankings, 2018/19) and among the oldest in England. King's has more than 31,000 students (including more than 12,800 postgraduates) from some 150 countries worldwide, and some 8,500 staff.
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World-changing ideas. Life-changing impact: https://www.kcl.ac.uk/news/headlines.aspx
About Asthma UK
- In the UK, 5.4 million people are currently receiving treatment for asthma: 1.1 million children (1 in 11) and 4.3 million adults (1 in 12).
- Every day, the lives of three families are devastated by the death of a loved one to an asthma attack, and tragically two thirds of these deaths are preventable.
- Asthma UK's mission is to stop asthma attacks and cure asthma. We do this by funding world leading research, campaigning for improved care and supporting people to reduce their risk of a potentially life-threatening asthma attack.
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The Lancet Public Health