They say that cycling is good for your wellbeing, and for environmental wellness. Not only do you get fitter; you also reduce your carbon footprint – win-win. However, when you’re cycling behind a fuming bus or taxi, and inhale that diesel-esque aroma, do you ever wonder: is this really the “wellness” option?
According to environmental wellness expert Peter Walker, ‘Cycling does remain many, many times better for your health than not cycling, even factoring in exposure to pollution and the risk of accident. What’s more surprising is that on two wheels you might even be exposed to less of the smelly stuff than those using other forms of transport. The more full answer is, inevitably, slightly mixed. Air pollution is a very real danger, with even conservative estimates gauging it prematurely kills almost 30,000 Britons a year, making it the most deadly public health hazard apart from smoking. And yet, experts say, there are a range of measures cyclists can take to limit their exposure, from taking quieter back routes, to cycling at particular times of the day. There’s even an argument that pollution masks, once common in cities like London but little seen these days, might help.’
With urban areas, the real villain behind the peril is the diesel engine, says Gary Fuller, an expert on air quality at King’s College London. Unlike petrol vehicles, which have somewhat cleaned up their emissions in recent years, diesels still emit lots of black carbon. Fuller warns, ‘People should be worrying about diesel traffic and particle exposure, and also about nitrogen dioxide. The thing about these is they haven’t really improved in urban areas for the last decade or so. We’ve managed to clean up air pollution emissions in terms of nitrogen dioxide from petrol cars. Buy a petrol car today and it will emit about four-tenths as much in oxides as a car you bought 10 or 12 years ago. But for diesels, despite the fact we have ever-tighter emissions standards the conditions in which the emissions test is performed doesn’t really reflect the real world.’
If you’re reading this and thinking: “That’s OK, I don’t live in London,” Fuller points out that diesel pollution is an issue for cyclists everywhere. ‘It’s not just a London problem,’ he says. ‘You can go out into apparently rural areas with an A-road travelling through a small village and you can find EU limits being exceeded.’ So, as a cyclist, what can you do to limit your exposure? Walker notes, ‘One simple idea is to take quieter back streets, where the concentration of some pollutants can be considerably lower than on main roads. As an illustration, the London Air website provides a live map of smog levels in the capital, showing how so much of it is clustered around big roads.’
It might also be a good idea to consider when you cycle, Fuller advises, as ozone can peak in the afternoon – especially in the summer – and this can have a significant effect on your lung wellness. ‘Ozone follows a distinct diurnal pattern,’ Fuller explains. ‘It’s always greatest in the mid to late afternoon. It’s not so much for urban cyclists but if you’re looking to have a day out on the bike maybe think about travelling in the morning and then the evening, avoiding the mid afternoon on the hottest, most polluted days. That can reduce your exposure quite a lot.’ King’s College London academic, Ian Mudway, an expert on respiratory toxicology, points to research that shows masks can filter out some smog. He comments, ‘I might say that people who wear them probably overestimate the benefits that they’re delivering, but I think there’s enough in that paper to say they make some difference.’
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