The health benefits of walking and cycling outweigh the negative effects of poor air quality, even in cities like London with high levels of air pollution, according to a new study.
Researchers from Cambridge University calculated that ‘air pollution risks will not negate the health benefits of active travel in the vast majority of urban areas worldwide’.
They said the new evidence strengthens the case for supporting cycling even in polluted cities, which can in turn can help reduce vehicle emissions.
The study supported the case for cycling infrastructure
Senior author Dr James Woodcock said: ‘Whilst this research demonstrates the benefits of physical activity in spite of air quality, it is not an argument for inaction in combatting pollution. It provides further support for investment in infrastructure to get people out of their cars and onto their feet or their bikes – which can itself reduce pollution levels at the same time as supporting physical activity.’
Although active travel such as walking and cycling is a way for people to increase their physical activity, concern has been raised about the risk from air pollution in urban environments.
A recent report suggested that air pollution, much of which comes from transport, contributes to around 40,000 early deaths in the UK every year.
Previous studies conducted in developed countries found that the health benefits of active travel are greater than the risks, but these were undertaken in areas of relatively low pollution, and their applicability to more polluted cities, particularly in emerging economies, has been unclear.
The new study is the first to model the risks and benefits of walking and cycling across a range of air pollution concentrations around the world.
The researchers calculated that only 1% of cities in the World Health Organization’s Ambient Air Pollution Database had pollution levels so high that the risks of air pollution could start to overcome the benefits of physical activity after half an hour of cycling every day.
Dr Marko Tainio, who led the study, said: ‘Our model indicates that in London health benefits of active travel always outweigh the risk from pollution. Even in Delhi, one of the most polluted cities in the world – with pollution levels ten times those in London – people would need to cycle over five hours per week before the pollution risks outweigh the health benefits.’
