Cycling and Exposure to Air Pollution

If you really care about the quality of London’s air, it is not enough to just harangue Mayor Boris on the weakness of his air quality strategy. If you do as he does and actually get on your bike then you are surely doing your bit to reduce air pollution in the capital.

Cycling is good exercise too. Remember, we are advised to take 30 minutes of moderately vigorous exercise five times a week on average, to optimise physical and mental health (the duration and intensity varying with your age and level of health and fitness, of course). Did you know cycling uses up to 650 calories an hour and that makes it great for weight loss and body toning? Another benefit of cycling is that it may help boost your levels of vitamin D through exposure to sunlight (there’s mounting evidence that low levels of vitamin D are implicated in many chronic diseases, and the sunshine vitamin is important for far more than just bone health). Cycling is a good use of your time as well. I discovered that the same four-mile journey in central London by bike takes just over half the time it takes in a car.

Of course, we all worry about safety when cycling. There’s good advice on the London Cycling Campaign website about how to behave on the road and how to get yourself properly kitted out for cycling. But you might also be concerned that cycling in London puts your long-term health at risk by exposure to air pollution. A recent study published in The Lancet is hardly reassuring - for it suggests that exposure to air pollution through cycling (or driving) to work might be a significant factor in triggering a heart attack. While there are lots of other risk factors for heart disease, and cycling, in general, improves your heart health, I think cyclists need to be given more information on the potential risks of pollution on the road.

A recent piece on BBC News highlights some of the issues. It points out that cyclists breathe more deeply, because of the physical exertion of cycling, than car users or people on public transport do; this might lead to cyclists inhaling more of the particulate matter that has been linked to heart and lung problems. But other research suggests that the limited ventilation inside a car or bus leads to higher exposure to pollutions, while cyclists are less exposed because they are in motion most of the time. Which is more important? We need some proper studies! One thing is for sure, you have to be careful when comparing driving in a car to riding a bike, scooter or motorcycle when it comes to exposure to air pollution. The reason is that most cars have proper filters in their ventilation systems so that the actual exposure to particle pollution is significantly limited if they are using the cars ventilation or air conditioning system.

If you are on a bike, scooter or motorcycle, here are ways of minimising your exposure to air pollution:

• Plan your routes so you keep away from heavy traffic and traffic jams, commuter routes, and main roads.
• Try to keep as much distance from cars and buses in front of you.
• Seek out tree-lined avenues and parks. Trees and green spaces counteract pollution.
• Notice the routes black cabs take to avoid traffic - they will show you the best short cuts.
• When you are at the traffic lights, do not get stuck downwind of vehicles’ exhaust pipes - adjust your position so you are in front of vehicles, not behind (although not in front of the lights, of course).