AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Commuter’s Air Pollution Exposure: Ventilation Rate and Urban Design Are Major Factors in Cyclist’s Elevated Intake
NICHOLAS GOOD, Jennifer Peel, John Volckens, Colorado State University
Abstract Number: 294 Working Group: Aerosol Exposure
Abstract High air pollution exposures are often experienced when commuting. Cyclists may experience particularly high doses of air pollution as their ventilation rates are elevated. Few studies of commuter air pollution exposures have accounted for ventilation rate in a realistic setting. In this study, we quantify the differences in cyclist’s and driver’s air pollution exposure accounting for inhalation under realistic conditions and assess whether air pollution intake can be practically mitigated by choice of route.
Personal exposure to black carbon (BC), carbon monoxide (CO), PM2.5 (the mass of particles < 2.5μm in diameter), and particle number (PN) were measured for 45 commuters over approximately 700 commutes. Each commuter drove and cycled to and from their workplace via direct and alternative routes designed to lower exposure levels. Commuter’s inhalation was modeled using their measured heart rate. Trip duration and minute ventilation rate are major determinates of commuter’s exposure. On comparable direct routes cyclists inhaled: 460% [95% Confidence Interval (CI): 306%, 638%] more BC, 98% [95% CI: 38%, 173%] more CO, 727% [95% CI: 435%, 1073%] more PM2.5, and 552% [95% CI: 263%, 1010%] more PN than when driving. By taking routes that avoid traffic cyclists saw relatively small reductions in the amount of pollution they inhaled: -36% [95% CI: -53%, -8%] less BC, -44% [95% CI: -63%, -15%] less CO, -26% [95% CI: -53%, 15%] less PM2.5, and -9% [95% CI: -46%, 62%] less PN. Relatively modest differences in commuter’s mean exposure levels are strongly modified by differences in their route and mode dependent minute ventilation rate and trip duration. The available alternative routes, designed to separate cyclists from their main source of exposure (motor vehicles), are of limited use.