Bicycle Network: Health Matters
Pollution and you
Worried about sucking in traffic fumes while riding? Simon Vincett investigates air pollution and how bike riders can deal with it.
You might think that traffic fumes affect bike riders more than anyone else, what with all that heavy breathing and apparently high exposure. But a recent Australian study has found that motorists are exposed to more harm.
The good news
A 2004 Sydney study, published in the Health Promotion Journal of Australia, looked at the exposure levels of commuters using different modes of transport - including cycling and driving - to five air pollutants (benzene, toluene, ethylbenzene, xylene and nitrogen dioxide).
The study found that motorists registered the highest levels for all pollutants except nitrogen dioxide, while "cycling commuters had significantly lower levels of exposure to benzene compared with car commuters".
Dr Chris Rissel of the Central Sydney Area Health Service, one of the authors of the study, explains: "There are two competing explanations for our findings: the tunnel effect, where everybody is travelling in the same polluted corridors, and the leaking of the exhaust and fuel systems into vehicles."
So while cyclists are often able to take routes with little or no motor traffic and produce no pollution themselves, motorists get a double dose from vehicles around them and their own cars. High levels of benzene exposure for motorists in particular can be due only to the leaking of their own vehicle fuel system.
A similar European study in 1995, found that "even when account is taken of effort (a cyclist breathes on average two to three times as much as a motorist), the cyclist emerges as the victor of this comparison" (quoted in Cycling: the way ahead for cities and towns).
Victorian health professional Dr Jan Garrard points out that a regular cyclist is better able to deal with air pollution as well: "Physical activity enhances the immune system, so in general terms a fit person will have a stronger immune system".
The Sydney study concludes with a key recommendation that "people travelling to work in peak-hour periods should use alternatives to cars to reduce their exposure to air pollutants, and also to reduce the exposure of other commuters by reducing their contribution to car emissions".
The harsh reality
Air pollution is undeniably a danger to health. Chris Marden commuted by bicycle to his Biochemical Engineering job at CSIRO for 15 years, from Elsternwick to South Melbourne initially, then 10km every day to Clayton and back.
After more than a decade of cycle commuting, Marden developed a respiratory condition called Sarcoidosis, an inflammation of the lungs that cut his breathing capacity to one quarter and permanently scarred his lungs.
"My doctors don't know what caused the condition - it's an auto-immune reaction, to do with the lymph system, and not easy to pin down to a precise cause - but the car fumes don't help," Marden explains.
Marden was prescribed anti-inflammatory medication and gave up riding during the worst bouts of the condition. Unfortunately he found the only other viable means of commuting to work was by car.
A paper prepared for VicHealth, The relationship between transport and health, corroborates the link between air pollution and respiratory diseases when it points out "it is accepted that the pollutants contribute to exacerbating or triggering an existing condition or tendency".
Dealing with pollution
You don't have to stay too far away from busy roads to avoid the worst exposure to pollution. Even the elevated position of upright bikes helps keep riders out of harm's way. Vehicle emissions quickly dissipate. The EPA Victoria points out that "levels [of vehicle emissions] are highest in regions with high traffic densities such as the CBD, inner-Melbourne residential areas and along major arterial routes".
Try these techniques:
Take paths, local roads and routes with less motor traffic whenever possible
Ride before or after peak hour
Keep some distance from motor vehicle exhausts
Move out in front of motor vehicles when stopped at lights.
Chertok, Michael, Voukelatos, Alexander, Sheppeard, Vicky and Rissel, Chris 2004 'Comparison of air pollution for five commuting modes in Sydney - car, train, bus, bicycle and walking' Health Promotion Journal of Australia vol. 15, pp. 63-7.
Dekoster, J and Schollaert, U 1999 Cycling: the way ahead for cities and towns European Commission, Luxembourg.
Van Wijnen, Verhoeff, Van Bruggen, Henk 1995 'The exposure of cyclists, car drivers and pedestrians to traffic-related air pollutants' International Archives of Occupational and Environmental Health vol. 67, pp. 187-93.
www.vichealth.vic.gov.au/rhadmin/articles/files/vhtransch2.doc (Accessed June 05; link expired) See Publications: Planning healthy environments
www.epa.vic.gov.au/Air/Issues/pub426.asp (Accessed May 05; link expired) See Motor vehicle emissions and air quality
London Cyclist Blog on Cycling masks and the shocking results
We market a very effective Personal Nasal Filter developed through NASA which contains activated carbon/cellulose filters. These filters inserted into the nasal cavities trap particles of exhaust fumes and smoke to protect the health of the wearer whilst cycling. nasalfilters.net