Thousands of COPD & asthma hospitalisations due to London's poor air

05 April 2019
  • Study by King’s College London and Imperial College London finds capital’s poor air quality leads to around 1,000 London hospital admissions for asthma and serious lung conditions every year
  • Between 2014-16, a quarter of those admitted with airway diseases were children under 14 with asthma
  • The Mayor’s central London Ultra Low Emission Zone will launch on Monday 8 April, reducing harmful emissions


New research, commissioned by the Mayor of London, Sadiq Khan, has found on average four Londoners, including one child, are hospitalised every day due to asthma caused by air pollution.


The research by King’s College London and Imperial College London estimated that between 2014 – 2016 more than 4,000 Londoners were hospitalised because air pollution worsened their asthma or, in the elderly, serious lung conditions.


Around 1,000 of those hospital admissions were of children under the age of 14. Asthma is the most common reason for urgent admissions to hospital in children in England. The total number of asthma admissions for children in London over the period of this study was 11,000 – meaning almost 10% of children’s asthma admissions are due to London’s air pollution.


Older people were also badly affected, with a high number of over-65s also suffering from the serious lung condition chronic obstructive pulmonary disease, COPD, which is made worse by air pollution. On average, over the period of the study, two Londoners over the age of 65 were hospitalised every day due asthma or COPD exacerbated by air pollution.


London’s toxic air is a health crisis that currently leads to thousands of premature deaths each year, harms lung development in children, and increases the risk of a range of illnesses from asthma to cancer, and from strokes to dementia*, with an economic cost to the capital of £3.7 billion every year.


This is why, on Monday 8th April, Sadiq is launching the world-leading Ultra Low Emission Zone (ULEZ) in central London. Operating 24 hours a day, 7 days a week, most vehicles including cars and vans will need to meet new, tighter emissions standards or be liable for a daily charge to drive in the zone.


With road transport responsible for around half of air pollutants, the central London ULEZ aims to reduce toxic emissions from road transport by around 45 per cent.


The ULEZ is an essential part of a series of bold measures the Mayor is taking to tackle London’s filthy air, from cleaning up the bus fleet and taxi fleet to introducing 12 Low Emission Bus Zones in some of the capital’s worst air quality hotspots, and rolling out rapid electric charging infrastructure. 

Together, these measures will ensure that by 2025 London’s air will be within legal pollution limits for the first time and there will be no London primary and secondary schools in areas of toxic pollution – there are currently 451.


It is estimated 600,000 people in London suffer from asthma, including 240,000 children. Two thirds of people with asthma say air pollution leaves them fighting for breath**.  While hospitalisation due to asthma can be a relatively rare occurrence, it is still extremely serious. However, many more people with the condition who do not go to hospital are still affected by high levels of air pollution and have to use their medication, for example inhalers, more frequently.


The Mayor of London, Sadiq Khan said: “As someone who developed adult-onset asthma over the last few years, I know from personal experience that London's toxic air is damaging people's health.

“This study is a stark reminder that air pollution disproportionately affects the most vulnerable Londoners and I’m doing everything in my power to protect children, the elderly and those with respiratory conditions from our filthy air.


“That’s why next week I’ll be launching the world’s first 24-hour seven-day-a-week Ultra Low Emission Zone in the central London Congestion Charge zone, which will help clean our air and reduce harmful road transport emissions in central London by an estimated 45 per cent.


Dr Heather Walton, Senior Lecturer in Environmental Health at King’s College London said: “It has been known for some time that air pollution exacerbates asthma but health impact assessments usually quantify respiratory hospital admissions overall. 


“This study provides separate estimates for asthma admissions in children and adults and for asthma/COPD admissions in the elderly. 


“Analysing the health impacts of poor air quality is a core component of King’s civic responsibility and these results highlight that reducing air pollution in London should provide important benefits for asthmatic and COPD patients.”


Dr Penny Woods, Chief Executive of the British Lung Foundation, said: “These figures are terrible – but sadly, not surprising. We know toxic air can worsen symptoms for people with heart and lung conditions, as well as stunt the growth of children’s little lungs and put everyone at risk of lung cancer and respiratory disease. It’s the biggest environmental threat to human health, yet because it’s invisible it’s often ignored.


“It’s important to note not everyone who is affected by air pollution ends up in hospital – thousands with conditions such as chronic obstructive pulmonary disease will avoid leaving the house because the air makes it that much harder to breathe. This isn’t fair, and it’s not right. We need to see tough measure put in place to make the air safe for Londoners – and everyone across the UK – to breathe.”


Dr Samantha Walker, Director of Research and Policy at Asthma UK said:

“Toxic air is a major threat to the nation’s health, so we welcome the ULEZ in London, which could pave the way to safer air for people with asthma.


“Around 400,000 people in London with asthma could be affected by air pollution**, leaving them struggling to breathe, in and out of hospital and at risk of a having a life-threatening asthma attack.

"A study part-funded by Asthma UK on the impact of London’s Low-Emission Zone (LEZ) found that after the zone was put in place children had lower levels of nitrogen oxide gases in their lungs. The new Ultra-Low Emission Zone will have even stricter standards on diesel exhaust emissions and we are hopeful it will reduce air pollution and keep people with asthma safe. The Government must commit to targets that reduce toxic air across the UK to the legal levels recommended by the World Health Organization, so that everyone with asthma can breathe clean air.” 

Notes to editors


Every breath we take: the lifelong impact of air pollution, Royal College of Physicians, March 2016 

** Falling through the gaps: why more people need basic asthma care. Asthma UK’s Annual asthma survey 2017:


The central London ULEZ launches on 8 April 2019 in the current Congestion Charge zone. This will replace the existing T-Charge and is in addition to the Congestion Charge. For cars entering the zone that don’t meet strict new emission standards there will be two ULEZ charge levels: £12.50 a day for cars, vans and motorbikes and £100 a day for lorries, buses and coaches. TfL’s online ULEZ vehicle compliance checking tool has been used more than 3 million times:


Airway diseases are an informal term referring to asthma and chronic obstructive pulmonary disease (COPD).  These involve narrowing of the airways in the lung so that it is harder to breathe out quickly.  This is reversible with an inhaler in asthmatics but not fully reversible in COPD patients.  The study combined COPD and asthma in the elderly because COPD is more common in the elderly and asthma and COPD can be hard to distinguish in the elderly.


 If you suffer from asthma and are concerned about how air pollution may affect your health, Asthma UK’s website provides guidance on how to stay safe with your asthma on high pollution days:


For more information on the study please visit:


Asthma UK’s report Falling Through The Gaps: Why More People Need Basic Asthma Care, surveyed more than 7,000 people with asthma in the UK. Of the 601 people from London, 73.5% said air pollution triggered their asthma. To find the estimated number of people with asthma in the London who said air pollution triggered their asthma, Asthma UK applied this proportion to the population of people with asthma in the London (665,000), to get a figure of 489,200.

Estimate of England prevalence from Health surveys. (Health survey for England, 2001; Scottish Health survey, 2003; Welsh Health survey, 2005/06; Northern Ireland Health and Wellbeing survey, 2005/06. Data accessed via UK Data Service). Estimate of prevalence in London based on England estimate and the proportion of the population living in London (14.79%) (From Office of National Statistics, 2008).


Sadiq Khan believes it is important that Londoners are fully informed about toxic air quality and since being elected has delivered a comprehensive air quality alert system to be activated. This system uses bus countdown signs, roadside signs and electronic updates at underground stations, plus social media and text alerts to inform the public in advance of high air pollution episodes.





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