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Most London hospitals and clinics exceed air pollution limits

BMJ 2017; 357 doi: (Published 14 June 2017) Cite this as: BMJ 2017;357:j2855
+ + This graphic is a collaboration between The BMJ, King’s College London and the UK Health Alliance on Climate Change
  1. Pauline Castres, policy and communications officer1,
  2. David Dajnak, principal air quality scientist2,
  3. Melissa Lott, energy systems engineer and writer3,
  4. Nick Watts, director1
  1. 1UK Health Alliance on Climate Change
  2. 2Environmental Research Group, King’s College London
  3. 3University College London
  1. pauline.castres{at}

More than half of London’s NHS facilities are blanketed in air pollution that is above legal limits, shows new analysis jointly published by King’s College London and the UK Health Alliance on Climate Change. Health professionals are having to care for their patients in environments where air pollution could aggravate existing illnesses. NHS staff are among those exposed to this health risk, but it is patients’ health that is of most concern, especially children’s.

Air pollutants, and in particular fine particles and nitrogen dioxide, damage our health throughout our lifetime, from before birth and well into old age. Robust scientific evidence has linked poor air quality to an increased prevalence of ischaemic heart disease, cerebrovascular accidents, chronic obstructive pulmonary disease, asthma, and lung cancer.1 Emerging evidence indicates a link between exposure to air pollution and type 2 diabetes, obesity, and dementia.2

Toxins and particulates are pumped into the air by our cars and power plants, damaging our health in the short term. In the long term the same activities produce carbon dioxide, driving climate change and potentially harming human health through stronger storms, more frequent floods and heatwaves, and the spread of infectious diseases such as malaria and dengue fever.

Not only does air pollution affect infants’ and children’s health as their hearts and lungs develop, it also disproportionately affects the most vulnerable people, including older adults and people with pre-existing conditions who need to travel regularly to health centres and clinics for care and treatment. This week doctors, nurses, and allied healthcare professionals took part in the UK’s first ever national clean air day (Thursday 15 June) to highlight the challenges we face from air pollution and climate change. The day was part of a global effort, “Unmask My City” (, led by health professionals around the world.

Researchers from the Environmental Research Group at King’s College London worked with the campaigning group the UK Health Alliance on Climate Change to create an air pollution map of London’s NHS facilities. In their analysis the King’s College researchers looked at the air quality at 2200 medical facilities, including London’s major hospitals, several general practices, clinics, and general health facilities, using data from the Greater London Authority and Transport for London. Sites were identified from 2834 records taken from NHS Digital’s Organisation Reference Data, published in April 2017. These sites ranged from acute care facilities to community and outreach sites. Single sites may appear several times in this visualisation if they accommodate services provided by more than one NHS trust. The visualisation is not exhaustive: 634 records, including a large number of duplicates, don’t appear because of the difficulty of matching all sites with pollution data in a short production timeframe. Each London medical facilities’ postcode was intersected with the air quality concentration points from King’s KCL urban model (described by Beevers and colleagues3) at a resolution of 20 m by 20 m and using predicted concentrations of nitrogen dioxide, PM10 (particulate matter of diameter 2.5-10 μm), and PM2.5 (<2.5 μm) taken from the latest available data (2013) in the London Atmospheric Emissions Inventory (

The BMJ’s accompanying infographic shows levels of air pollution at each individual site and includes an average nitrogen dioxide concentration, produced by averaging all the concentration points in each London medical facilities’ postcode, and the maximum concentration in each postcode. Both are useful health indicators, as the average relates to the cardiovascular disease and stroke burden, while the maximum relates to the exacerbated asthma and chronic obstructive pulmonary disease burden.

The results show that health facilities throughout the city are affected by air pollution. In particular, 74% of facilities in inner London and 41% in outer London are in areas where nitrogen dioxide levels are above the legal limit. Several of England’s largest acute care trusts and teaching hospitals are located in central London, and patients from across the UK visit these sites.

The findings mirror other studies showing that vulnerable groups are disproportionately exposed to air pollution. One recent study found that most nurseries in London are located in air pollution hotspots.4 The data analysis released today is additional proof that London’s air is toxic and especially harms the vulnerable among us.

This new finding should not put people off coming to hospitals, but it does show that across London air pollution is a major problem requiring immediate action. Because we cannot remove schools and hospitals from our city centres, we need to rethink our current transport model and shift to cleaner, greener transport and get more people walking and cycling. We need a series of hard hitting measures such as those described by London’s mayor, Sadiq Khan,5 not just in the capital but across the UK, as 38 of 43 UK areas are still breaching legal limits on nitrogen dioxide concentrations.6 As a matter of urgency local authorities in all the UK’s cities should analyse air pollution around health facilities.


  • We thank Peter Dutey-Magni for his assistance with NHS site information.

  • Londoners can check how their local health facilities fare by using the accompanying interactive map. You can tweet about the results using the hashtag #NHSair.


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