Ideal speed for cyclists and pedestrians to reduce pollution inhalation
Riding a bike is fun and great exercise too. It’s a fantastic way to get about and enjoy the scenery without causing any carbon emissions.
The transport sector is the largest contributor of greenhouse gases in Australia with an annual growth rate of 1.5%
The pollution caused by vehicles affects everybody including the 3.6 million Australians who ride a bike each week, counteracting the health benefits that they derive from cycling, as they inhale most of the air pollution.
The ideal speed for cyclists is between 12 to 15 kilometres per hour to minimise inhalation of toxic air pollutants and still derive health benefits of exercise.
Pedestrians and cyclists are most at risk as inhalation doses are high due to high breathing rates. But they are exposed to pollution for a shorter period of time compared to those that walk or cycle slower.
This analysis made researchers at The Department of Civil Engineering of The University of British Columbia, Canada realise that there must be an optimum speed which cyclists and pedestrians can move at to minimise inhalation of air pollution and still benefit from the activity undertaken. This is the ideal speed linked to the least pollution risk.
For this study the researchers used a sampled synthetic population of 10,000 people from the 2012 USA population census data to calculate ideal Travel speed or the minimum dose speed (MDS) for various age and sex groups. To determine the MDS, researchers derived data from previously established models of human ventilation and energy expenditure and applied different parameters at varying road grades. However the effects of stops, acceleration and ground-level wind was left for future study.
The MDS for female cyclists under the age of 20 was calculated at 12.5 kilometres per hour on average on a flat road. For male cyclists the MDS was 13.3 kilometres per hour for under 20’s. For the older age group of 20-60 years, the MDS was 13 kilometres for females and 15 kilometres for male cyclists.
Female and male pedestrians under 20 should walk at an average of 3 kilometres an hour whereas older pedestrian should walk at an average of 4 kilometres an hour to breath in the least amount of pollution.
The good news is that ideal speeds match pretty closely to actual cycling and walking speeds of people. But if the speed increases, then pollution inhalation will be significantly higher which will be detrimental to health.
With this kind of research, you now know what speeds are ideal for your walk or a bike ride through the city for you to reap benefits of your activity with the least amount of risk from pollution inhalation.
Getting up an about is leisurely, relaxing and healthy too and now you can do it at the best speed to minimise the risks from pollution.
Source: International Journal of Sustainable Transportation
