The Fort Collins Commuter Study: Impact of route type and transport mode on personal exposure to multiple air pollutants

Abstract

Traffic-related air pollution is associated with increased mortality and morbidity, yet few studies have examined strategies to reduce individual exposure while commuting. The present study aimed to quantify how choice of mode and route type affects personal exposure to air pollutants during commuting. We analyzed within-person difference in exposures to multiple air pollutants (black carbon (BC), carbon monoxide (CO), ultrafine particle number concentration (PNC), and fine particulate matter (PM2.5)) during commutes between the home and workplace for 45 participants. Participants completed 8 days of commuting by car and bicycle on direct and alternative (reduced traffic) routes. Mean within-person exposures to BC, PM2.5, and PNC were higher when commuting by cycling than when driving, but mean CO exposure was lower when cycling. Exposures to CO and BC were reduced when commuting along alternative routes. When cumulative exposure was considered, the benefits from cycling were attenuated, in the case of CO, or exacerbated, in the case of particulate exposures, owing to the increased duration of the commute. Although choice of route can reduce mean exposure, the effect of route length and duration often offsets these reductions when cumulative exposure is considered. Furthermore, increased ventilation rate when cycling may result in a more harmful dose than inhalation at a lower ventilation rate.

Characteristics and applications of small, portable gaseous air pollution monitors

“…These three gases are common criteria urban air pollutants that have been widely analyzed in the recent scientific literature and can be harmful to human health (e.g. Castell et al, 2013;Deville Cavellin et al, 2015;Good et al, 2015;Lin et al, 2015). The air pollution monitors were chosen based upon the availability and accessibility of the comparable information.…”

“…In order to advance environmental and human health studies, mobile air pollution monitors are increasingly used to obtain more accurate personal exposure estimates. Studies show that personal sampling of air pollution is preferable when attempting to accurately measure human exposure (Good et al, 2015;Steinle et al, 2013;Weichenthal et al, 2011;Zartarian et al, 2007), and that a high spatiotemporal resolution is required to correct for misinterpretation of actual exposure (Baxter et al, 2013;Kumar et al, 2013). Although there is a lack of concrete information on the effective use of such sensors by individuals and communities, specific vulnerable populations in urban areas could benefit from these sensor systems (e.g.…”

“…While there are many small monitors that measure particulate matter (PM) that have been widely used in mobile monitoring studies, these are not the focus of this review. For detailed reviews and further information on research and applications regarding PM spatial assessments and monitoring, the reader is referred to Jova sevi c-Stojanovi c et al (2015) and Gozzi et al (2015).…”

“…Honicky et al (2008) highlighted various challenges with the quality of air pollution sensor data from networked mobile monitors, challenges that include privacy, interference of user behavior, location coverage, calibration accuracy, and social aspects of mobile sensing. An active area of research involves examining the fundamental science behind collection methods, variability of common air pollutants in urban areas, and testing and validation of methods not using crowdsourcing (Cao and Thompson, 2016;Good et al, 2015;Mead et al, 2013;Van den Bossche et al, 2015). Here, researchers routinely cite the need for post-processing methods, such as background normalization, event detection, and corrections for sensor drift over long time scales to be applied for accurate assessment of measurements.…”

“…For example, Good et al (2015) studied the impact of route choice on air pollution exposure utilizing many separate instruments including small particle monitors, a CO sensor, and heart rate monitor, yet the techniques used were more advanced than those affordable or feasible for average citizens. However, the researchers provided notable findings, wherein a commute by car resulted in 15e20% higher exposures to CO than a commute by bicycle, consistent with related studies (De Nazelle et al, 2012;Kaur et al, 2005).…”