A multi-modal study of factors influencing the exposure and uptake of vehicle air pollution while commuting in Auckland City

Abstract

An ever increasing amount of evidence is emerging to link air pollution to adverse health effects, and a major portion of this pollution is encountered while commuting. This highlights the need to investigate the relationship between commuting and pollution uptake, as current air quality assessments are based on stationary monitors. Studies suggest that fixed monitoring stations are not representative of the true dose experienced by individuals, due to the fact that people are highly mobile. The modes of commuting tested were the car, bicycle, running and the university shuttle, and pollution levels were based on CO, as portable and inexpensive monitoring equipment is now available. It was recognized that the level of activity a person is undergoing will impact their pollution uptake, as will the commuting time. Hence not only were average exposures considered in the study but also the dose and uptake of commuters following the same route, at approximately the same time. Other factors considered were whether time of day, day of the week, type of environment and levels of CO encountered by shuttle drivers in a working day. Further facets of the study included a case study on wind speed effects and the evaluation of the representativeness of fixed monitoring stations. Results indicated that the most favourable modes of transport in terms of average CO exposure were the active modes, followed by the shuttles and then the car. The opposite was found to be true when considering the dose and uptake, and this was attributable to the increased breathing factor and commute times of the active modes. The results of the study further indicate that time of day, day of the week and road type are not as important in terms of CO uptake as is proximity to the road. This suggests that should the eco-friendly active modes of transport be advocated, the runners and cyclists need to be a sufficient distance from the road in order to ensure their uptakes of pollutants are minimised. Levels of CO in Auckland City recorded by the FMS were found to be minimal, and well below recommended guidelines.