High-speed cyclists ‘breathe in dangerous levels of air pollution – raising their risk of lung cancer and stroke’
One scientist has worked out the ideal speed to travel when you're cycling or walking through a busy city... to reduce the risk to your health
LYCRA louts who whizz through the city streets may be doing themselves more harm than good by breathing in too much air pollution as they exercise, experts claim.
High-speed cyclists and even brisk walkers breathe more deeply into their lungs, drawing in toxic road smog - and increasing their risk of lung cancer, stroke and other nasty illnesses.
But, on the flip side, travelling quickly means less time spent actually being exposed to pollution.
Air pollution now kills 16,355 people in Britain every single year, while studies suggest simply living near a busy road could cause your blood pressure to soar, possibly leading to a heart attack.
In a bid to reverse this trend, University of British Colombia scientists have worked out the optimal speeds for walking and cycling – to minimise their inhalation of air pollution while still getting the health benefits of exercise.
Facts on air pollution
* Air pollution increases the risk of asthma, stroke, respiratory disease and lung cancer.
* The latest figures revealed air pollution kills 16,355 Brits a year.
* Nine out of ten Brits are now living in areas where pollution is above the 'safe' limit.
How to reduce your pollution exposure
1. Avoiding busy roads could reduce the amount of pollution you breathe in by 70%.
2. Wearing a mask can help filter out large pollution particles, but they must be close fitting and not cause breathing difficulties.
3. Leave your car at home - you will be exposed to pollution while driving, too.
4. If possible, avoid cycling during rush hour.
5. Avoid waiting beside lorries and other large diesel vehicles at junction and when queuing.
Five simple steps from breathelondon.org/south-east/cycling
They reckon cyclists should ride between 7.5mph (12kph) and 12.4mph (20kph) on city roads, while pedestrians should walk at between 1.2mph (2kph) and 3.7mph (6kph).
The University of British Colombia's guide depends on age, with older people being advised to take it more slowly – and women shouldn't attempt to keep up with blokes.
Assistant Professor Dr Alex Bigazzi said: "The faster you move, the harder you breathe and the more pollution you could potentially inhale, but you also are exposed to traffic for a shorter period of time.
"This analysis shows where the sweet spot is."
The dirty dozen: The UK's most toxic cities
1. Port Talbot
2. Stanford Le-Hope
3. Glasgow
4. Leeds
5. London
6. Scunthorpe
7. Eastbourne
8. Nottingham
9. Oxford
10. Southampton
11. Middlesbrough
12. Stoke-on-Trent
The estimates were calculated using a US Census-based computer model of 10,000 people – and assume that people are travelling on flat roads or pavements.
For teenage female cyclists, the ideal speed is 7.8mph (12.5kph), while for young male cyclists it's 8.3mph (13.3mph).
For those between the ages of 20 and 60, the best speed was between 8mph (13kph) and 9.3mph (15kph).
For child and teenage pedestrians, the ideal walking pace is 1.9mph (3kph), while older people should strive to reach 2.5mph (4kph) to breathe in the least amount of pollution during each trip.
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Prof Bigazzi said: "If you move at much faster speeds than the MDS (minimum dose speeds), say, cycling around 6.2mph (10kph) faster than the optimal range, your inhalation of air pollution is significantly higher.
";The good news is, the MDS numbers align pretty closely with how fast most people actually travel."
He now plans further research of the MDS on real roads. The study was published in the International Journal of Sustainable Transportation.