Watch: Why is air pollution a problem?

Air pollution contributes to around 40,000 premature deaths in the UK each year and is linked to heart attack and stroke. Lucy Trevallion looks at this invisible problem and how you can reduce your risk.


The UK government's plans to tackle air pollution were deemed “woefully inadequate”. That’s what it was told by the High Court in November, in a case brought by environmental charity ClientEarth. This wasn’t the first time the government has been taken to court over its poor air pollution plans. In 2015 the government was ordered to make plans to bring air pollution within legal limits.

London has the worst air pollution in the UK, followed by Birmingham, Manchester and Bristol (air pollution is usually worst in cities). At sites in London, air pollution levels are monitored hourly and must not exceed a set limit (200 micrograms of nitrogen dioxide per cubic metre) more than 18 times a year. But in 2016 this limit was broken at 59 of the 97 measurement sites.

The air pollution problem

You can’t see it, but it is there: an invisible problem. Since the particles are so small – around a quarter of the width of a strand of hair – they can get into the bloodstream and go on to cause widespread damage. Professor Frank Kelly, Director of the Environmental Research Group at King’s College London, explains: “All of the organs in the body seem to be affected in some way by breathing in air pollution.”

All of the organs in the body seem to be affected in some way by breathing in air pollution

Professor Frank Kelly

Some of the biggest problems are the increased risk of heart and circulatory disease, or the worsening of these conditions for people already affected by them. Thanks to BHF-funded researchers at the University of Edinburgh, we now know a lot more about how air pollution affects your heart. Dr Nick Mills, Senior Clinical Research Fellow at our Centre of Research Excellence, says: “We found that tiny ‘nano-particles’ in diesel exhaust produce highly reactive molecules called free radicals that can injure blood vessels. These nano-particles – less than a thousandth of a millimetre wide – prevent blood vessels from relaxing and contracting properly. The disturbance to blood vessel function means there is an increased risk of clots developing in coronary arteries, which can cause a heart attack.”

Recent BHF research has also shown a strong association between short-term exposure to air pollution and admission to hospital for stroke and death from stroke. Other research suggests that breathing in air pollution can lead to atherosclerosis – the build-up of fatty material inside the arteries that can lead to a heart attack.

Blood supply to the brain is also affected, so the risk of developing conditions like dementia will increase too.

Professor Kelly says: “It’s estimated that those who die prematurely in the UK are losing on average six months of life due to air pollution exposure. The people who die prematurely in London will be dying up to maybe 10 years earlier than they should.”

Air pollution exposure in the womb has been linked to premature births, health problems and behavioural difficulties in children.

Cars in London alongside cyclists and pedestrians

How to protect yourself from air pollution

But there are easy ways to protect yourself from air pollution:

Professor Kelly says: “A diet high in antioxidants [found mostly in plant-based foods] can help defend you against these oxidant pollutants, making you less susceptible to the negative effects of air pollution.”

Even a few metres away from traffic can reduce your exposure

But should you exercise if you’re in an area with high air pollution? For most people in the UK and Europe, outdoor physical activity has overwhelming health benefits compared with the potential risk of air pollution. Even in high-pollution areas, benefits usually outweigh risks.

Dr Audrey de Nazelle, Lecturer in Air Pollution Management at Imperial College London, suggests people walk or where possible (air pollution levels are usually higher in a car). Choose routes away from traffic, she says even a few metres away from traffic can make a difference. “If you’re walking on a wide pavement, walk as far from the road as possible. If you’re cycling, you’re better off on a segregated cycle lane, but even better on a side road,” she says.

Public Health England advises that when pollution is a moderate level, adults with heart problems, or who experience symptoms such as sore eyes or a cough, should consider reducing strenuous physical activity, particularly outdoors.

  • You can get air pollution updates by visiting the DEFRA website or calling 800 55 66 77 for recorded information.
  • Read our full air pollution policy

Taking action

A red London bus

Two of the most common and harmful types of air pollution are particulate matter (mostly from road traffic and industry) and nitrogen dioxide (largely from vehicles and power stations).

Dr de Nazelle says: “In the centre of London, about 50 per cent of NO2 and particulate matter is from road transport. Transport is where we can have the most impact at a local level.”

A spokesperson for Defra (the Department for Environment, Food & Rural Affairs) says: “We are firmly committed to improving the UK’s air quality and cutting harmful emissions. That’s why we have committed more than £2bn since 2011 to increase the uptake of ultra-low emissions vehicles, support greener transport schemes and set out how we will improve air quality through a new programme of Clean Air Zones. We will update our air quality plans in the spring.”

London Mayor Sadiq Khan promised to reduce air pollution by introducing an ultralow emission zone, more electric charging points, and more electric or hybrid buses.

Since 2010 the BHF has provided £3.2m to research the link between air pollution and heart and circulatory disease. David McColgan, BHF UK policy lead for air pollution, says: “We want to elevate the debate around air pollution and tackle poor air quality across the country. Air pollution is a priority in our prevention agenda.” 

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