While the health benefits of exercise via cycling are estimated to substantially exceed any health impacts related to air pollution exposure or injuries from traffic accidents, cyclists are known to experience elevated exposures to traffic-related air pollutants. In addition, our research on cycling motivators and deterrents identified air pollution and traffic as major factors influencing the choice to make a trip by bicycle.
The objective of this study is to investigate the relationship between traffic-related air pollution exposure and respiratory and cardiovascular health impacts in commuting cyclists. Specifically, we are
- determining commuting cyclists’ exposure to traffic-related air pollutants (PM 2.5, PM10, ultrafine particulate) while cycling along two different bicycle routes in the city of Vancouver;
- estimating the pollutant dose received by each cyclist, and relating this to the health effects observed; and
- determining if there is a change in lung function, endothelial function, and C-reactive protein level related to the level of air pollution exposure and dose.
An article in the Huffington Post outlines the issues.
This study uses a randomized (single) blinded crossover design. Each subject bicycles along two separate routes, while air pollutant levels along each of the routes are measured. Before and after each cycling session, subjects’ lung function and endothelial dysfunction are measured and a blood sample is collected. While cycling, subjects wear a heart rate monitor, and a cycling computer measures and records their work rate. At the end of each cycling session subjects’ minute ventilation is measured and related to their heart rate and work rate by cycling in the laboratory on a stationary bike while breathing into a respirometer. The health endpoints are microvascular function, lung function and markers of inflammation.
In comparisons of health indicators after cycling downtown versus residential routes, cyclists had decreased endothelial function 1 hour after cycling on the more polluted downtown route. The downtown route had levels of ultra fine particulates ~ 60% higher than the residential route.
Active transportation is a non-polluting form of transportation, and is increasingly encouraged by public health agencies as a way to improve air quality as well as physical fitness. While exercise is promoted as healthy behaviour, cyclists may experience high doses of air pollution due to their elevated breathing rates and cycling in proximity to traffic, especially during periods of elevated air pollution. We will assess the potential health impacts of cyclists’ exposures, and learn if route choice impacts inhaled pollutant dose and cardiopulmonary health effects. The information from this study may be useful for providing advice to the public regarding where and when to cycle in order to achieve health benefits while at the same time minimizing potential adverse impacts related to air pollution exposure.