Cycling In A City Is Always Good For You, Despite The Pollution, Research Claims

Cycling In A City Is Always Good For You, Despite The Pollution, Research Claims

The benefits of physical activity from walking or cycling in British cities will always outweigh the risks of air pollution and injuries, scientists say. According to one study, it causes 9,500 premature deaths a year in the capital. Another report said it kills 40,000 a year nationwide.

You’re probably also aware that cycling and walking are good for you. But are they still good for you if you live in a major – and majorly polluted – city? The answer, according to a new study, is yes.

The study was carried out by scientists at the University of Cambridge and published in the journal Preventive Medicine, and it looked at whether “active travel” (cycling and walking) still does more good than harm if it means it exposes you to more air pollution. It compared the effect on “all-cause mortality” – how likely you are to die for any reason in a given period – of raised pollution levels versus active travel.

It found that even in the most polluted cities, cycling and walking is good for you.

The authors looked at the concentration of fine particulates in the air, measured in micrograms per cubic metre (μg/m3), as a measure of how polluted the air was in general. Then they used data from previous studies to estimate how harmful those levels of pollution would be. Delhi in India was the most polluted, at 153μg/m3.

“According to the WHO [World Health Organization], which collects data on air pollution in cities, there are 17 cities which have over 89mcg/m3 on average,” Dr Marko Tainio, one of the authors of the study. “Ten are in India.” (There are other cities with high pollution that aren’t included in the WHO’s data.)

But even in those cities, the study found, walking is better than not – the benefits to your health of doing exercise outweigh the costs. Cycling is also better, but, Tainio said, “cycling is more physically demanding on average than walking, so you’re inhaling more, so you get more [particulates] through your lungs”. That means up to an hour or so a day of cycling is good for you, according to the study, but after that the risks start to outweigh the benefits.

In less polluted cities – such as London and other British or Western cities – the study found that however much you cycle, it never stops being good for you.

“When we were looking at the London air pollution levels, cycling and walking was beneficial even if you were doing 16 hours a day,” said Tainio. He said he and his colleagues stopped looking beyond 16 hours, because it was unrealistic that people would be cycling that much.

The benefit is even clearer if instead of cycling or walking, you would otherwise have been taking your car.

Of course, air pollution isn’t the only risk cycling poses. But the authors say that, even when you take into account the danger of accidents, the benefits still hugely outweigh the risks.


Adapted from