Photo credit: Alvaro Tapia Hidalgo

 A pilot study last month shifted the spotlight back onto cycling and air pollution. Led by Prof Jonathan Grigg from Barts and the London School of Medicine, the study looked at 5 cyclists and 5 pedestrians, all healthy commuters aged between 18-40. According to this sample, cyclists were found to have 2.3 times the amount of black carbon in their lungs compared with pedestrians.

Many media outlets went into a flurry following the release of this study: BBC featured a headline stating that “Cyclists inhale double the soot”. Rather ironically, the Green Car Website in the UK touted a headline, “Why it may not be so healthy to cycle".

But before jumping to conclusions, it’s important to dig a little deeper into the literature around pollution and cycling. It should be remembered that this study compared walking and cycling, and not cycling and other forms of transport.  I had a chat to my colleague Benoit Blondel (ECF Health and Policy Officer) about whether or not my daily commute was killing me. Surely it must be better than getting into a car?

Benoit told me that: “For many years, studies have measured air pollution exposure levels associated with different modes of transport. Overall, air pollution exposures experienced by car drivers were found to be modestly higher than those experienced by cyclists”

But the situation isn’t all rosy. Benoit tells me that cyclists breathe harder and faster and so carbon (soot) may be higher in cyclists. The difference in exposure between cyclists and car drivers depends on a large number of factors. Indeed factors such as journey time should also be given attention. For example, a cyclist may travel quicker than a car in rush hour. This in theory could result in less exposure. Research has also shown that cyclists on quieter roads also have less exposure than those in carbon powered buses or cars. 

Perhaps a more sensible voice came from the Wall Street Journal who delved a little deeper than simplistic headlines in an article entitled: “A Different Spin on the Dangers of Urban Cycling”

The reporter noted that “The carbon figure was based on only a handful of cyclists in London” and “The five cyclists were older than the five non-cyclists, on average, and might have spent more time outside, and exposed to emissions, than those who didn't bike to work. The study didn't account for this disparity”. Indeed it should be remembered that this was a pilot study, and only had a sample size of ten people. 

At the end of the day however, the question should be whether or not the health benefits of cycling outweigh the risks? The author of the recent study, Prof Grigg stated that “"I still strongly suspect the benefit of cycling is going to outweigh the risks of inhaling more carbon.”

Grigg is right. According to research last year from the University of Utrecht, a 7.5 kilometre daily bicycle commute will wipe off 21 days of your life because of air pollution. But this is counter balanced by an 8 month average gain due to increased physical activity. So, for the cyclist, health benefits beat health harm by a factor of about 10.

In fact, perhaps this recent study could act as a catalyst for more cycling. We need to improve air quality reduce pollution at the source, and in many cities it is private motor vehicles that are the main contributors to air pollution.

If only the headlines stated: “Study finds that cars are killing us: Governments should push for more cyclists”. 

About the Author

Julian Ferguson is the Communications Officer for the European Cyclists’ Federation. Originally hailing from Australia and a keen bicycle advocate, he plans one day to ride his bicycle from Brussels to Melbourne