Cycling and Air Pollution

Cycling is generally regarded as the healthier and more environmentally friendly mode of travelling. But how safe are cyclists? We already know that cyclists are vulnerable road users and so are at greater risk of injury if they are involved in an accident. But what about their exposure to toxic fumes? Following on from the previous article on the damaging effects of diesel cars on the environment, this blog will look at emissions statistics and whether these emissions can cause harm to cyclists.

Road use statistics

The Department for Transport’s Road Use statistics from 2016, show that cyclists travelled over 3.5 billion miles that year, a number which has been on the increase for at least the last 20 years.[1] The increase in miles travelled could be indicative of an uptake in cycling, or that existing cyclists are travelling much further than they were before.

Almost 70% of these road miles were on urban minor and ‘A’ roads.[2] Comparing this to the total number of vehicle miles on urban roads, we can see that cycles only make up 2% of traffic on these roads. The other 98% of traffic on these roads consists of cars, vans, lorries and other vehicles which no doubt spew harmful fumes into the environment.


Are these fumes harmful to cyclists?

There is no dispute that air pollution can have negative impacts on human health and the environment[3], but exactly how harmful are these fumes?

Professor Chris Griffiths, GP and co-director of Asthma UK Centre for Applied Research, told the Guardian that he approves of the new toxicity charges being imposed on diesel cars driving in London, due to the level of harm they can cause to people’s lungs.[4] According to Professor Griffiths, the poor air quality increases the likelihood of a respiratory illness developing, especially in children.

This is reinforced by Dr Steve Iley, Medical Director of Bupa, in stating that air pollutants are linked to serious health problems such as chronic obstructive pulmonary disease (COPD), respiratory infections and lung cancer.[5] He also identifies that people are at a higher risk of ingesting these pollutants while exercising, as people breathe harder while they are exercising. From this viewpoint, cycling amidst high volumes of traffic can end up causing irreparable damage to your respiratory system.


Should we cycle in the city if it’s so harmful?

Cyclists shouldn’t have to wear a mask if they want to ride in the city, in fact, Dr Iley points out that masks can be counter-intuitive if not worn properly and can make breathing more difficult.[6] Equally, the levels of air pollution should not deter people from cycling in the city. The best advice in the opinion of Dr Iley and his colleague Dr Luttrell, is to plan your route so that you avoid the busier, more congested roads, or to journey at less busy times of the day.[7]

There is some argument that the benefits of cycling outweigh the negative effects of air pollution. Air pollution contributes to a significant number of premature deaths in the UK each year, but alternatively, regular exercise reduces the risk of diabetes, heart disease and several cancers.[8] So which has a greater impact on human health: air pollution or cycling?


Do the benefits of cycling outweigh the harmful effects of air pollution?

According to a study conducted by scientists at Cambridge University, there are more health benefits from cycling to work than there are negative effects from air pollution.[9]

The study suggests that it is only in some of the worlds most polluted cities where the detrimental effects of air pollution are more significant than the benefits of doing exercise. For example, in some cities in India, as little as 30 minutes cycling a day can undo the benefits of cycling.[10]

In fact, one of the study’s co-authors, Dr Audrey de Nazelle from the centre of environmental policy at Imperial College London claims that ‘the good news is that across the world, in 99% of cities it is safe to cycle for up to two hours a day.’[11] This provides some reassurance for cyclists on their morning commute to work. It was also claimed that ‘people in western cities such as London, Paris or New York would never reach the point where air pollution’s negatives outweigh exercise’s positives in the long term.’[12] Based on the evidence of this study it would appear that the benefits of cycling in UK cities and towns do outweigh the potential harm that air pollution can cause to your health.


Are there less harmful modes of transport?

Cycling and walking are regarded as the healthiest modes of transport, in terms of the amount of exercise done. However, it may also be the case that they are the healthiest modes of transport when talking about their exposure to air pollution.

An experiment conducted by the Healthy Air campaign in 2014 shows that cyclists who take much quieter routes during rush hour, experience far less air pollution than people who travel by car. [13] People travelling by car experienced the most exposure to pollution, whereas people who walk quieter routes experienced the least exposure to pollution. [14]

This study reconfirms the views of Dr Iley that quieter routes are less polluted, and so the healthiest mode of transport is to walk through quieter routes. In saying this, the experiment shows that cycling is still much better than driving or taking public transport.


What can be done to reduce the number of deaths caused by air pollution?

Around 40,000 deaths a year can be attributed to air pollution in the UK.[15] But what can actually be done to reduce the number of deaths?

The sustainable transport charity, Sustrans, has found that the number of deaths caused by air pollution could be reduced by over 12,000 within the next decade if the government reaches its goal to get more people walking and cycling.[16] In addition to this, saving over £900 million in associated costs may also be possible. Sustrans believes that investment in cycling and walking infrastructure is essential in order to combat the pollution crisis with the CEO urging the government to ‘prioritise investment in active travel as part of wider urgent action to make air safe again.’[17]



Air pollution has links to many respiratory illnesses and causes many deaths per year. Looking at the harmful effects of emissions, it may be easy to assume that cyclists are at a greater risk of harm as they are relatively exposed to the elements and breathe harder as they exercise. However, the reality is quite different, as the benefits of cycling outweigh the harmful effects that air pollution can have. It is only in the cities that are heavily polluted, in which cycling can cause more harm than good.

When looking at the alternatives, cyclists are exposed to less air pollution than drivers are. However, this still leaves motorists and those who use public transport at greater risk of feeling the damaging effects of air pollution. To tackle the overall problem of air pollution, investment in cycling and walking infrastructure may be required at Government level. This will help to reduce the number of deaths which occur and the amount of people who suffer with pollution related illnesses.



[1] Department for Transport, ’Road Traffic Estimates in Great Britain: 2016’ (Published 27th April 2017) 2 <>

[2] Department for Transport, ’Road Traffic Estimates in Great Britain: 2016’ (Published 27th April 2017) 18 <>

[3] Department for Environment, Food and Rural Affairs, ‘Air quality statistics in the UK 1987 to 2016’ (Published 27th April 2017) 2 <>

[4] The Guardian, ‘Air pollution is killing us. As a GP I welcome this new charge on drivers’ (Published 23rd October 2017) <>

[5] Bupa, ‘Air pollution in our cities: what you need to know’ (Published 16th January 2017) <>

[6] Bupa, ‘Air pollution in our cities: what you need to know’ (Published 16th January 2017) <>

[7] Bupa, ‘Air pollution and cycling: do I need to worry?’ (Published 10th July 2017) <>

[8] BBC News, ‘Air pollution: Benefits of cycling and walking outweigh harm – study’ (Published 5th May 2016) <>

[9] Cycling Weekly, ‘Benefits of cycling to work outweigh damage caused by pollution, study claims’ (Published 5th May 2016) <>

[10] The Guardian, ‘Tipping point: revealing the cities where exercise does more harm than good’ (Published 13th February 2017) <>

[11] The Guardian, ‘Benefits of cycling and walking “outweigh air pollution risk” in cities’ (Published 5th May 2016) <>

[12] The Guardian, ‘Tipping point: revealing the cities where exercise does more harm than good’ (Published 13th February 2017) <>

[13] Healthy Air, ‘Which transport option is the healthiest?’ (Published 12th August 2014) <>

[14] Healthy Air, ‘Which transport option is the healthiest?’ (Published 12th August 2014) <>

[15] Royal College of Physicians, Every Breath We Take: the Lifelong Impact of Air Pollution (Published 23rd February 2016) 3 <>

[16] Sustrans, The Role of Walking and Cycling in Solving the UK’s Air Quality Crisis (Published 4th December 2017) <>

[17] Sustrans, ‘Hitting UK cycling targets can prevent thousands of deaths from air pollution – new findings’ (Published 4th December 2017) <>