Review of Urban Bicyclists' Intake and Uptake of Traffic-Related Air Pollution

Abstract

Bicycling as a mode of transportation is enjoying a boost in many urban areas around the world. Although there are clear health benefits of increased physical activity while bicycling, bicyclists may experience increased inhalation of traffic-related air pollutants. Bicyclists have two to five times higher respiration rates than travelers in motorized vehicles and this difference increases with bicycle travel speed and exertion level. The main goal of this work is to review the state of knowledge regarding urban bicyclists' intake and uptake of traffic-related air pollution and to identify key knowledge gaps. This review includes not only bicyclists' exposure to air pollution concentrations but also respiration rates, intake doses (the amount of pollutant that is inhaled), and uptake doses (the amount of pollutant that is incorporated into the body). Research gaps and opportunities for future research are discussed. This is the first review to specifically address bicyclists' health risks from traffic-related air pollution and to explicitly include intake and uptake doses in addition to exposure concentrations for travelers.

Dynamic Ventilation and Power Output of Urban Bicyclists

“…Ventilation volumes are presented at ambient temperature and pressure, which allows direct application for inhalation rate estimates. Mean ventilation rate of 22.4 lpm (liters per minute) is in good agreement with past studies of bicyclist inhalation (2). The average sampling conditions were 17 kph travel speed (without stops), 19 °C (range: 11-25 °C), 75% relative humidity (range: 57-91%), and 1.8 mps wind speed (range: 0.6-3.6 mps).…”

“…Beyond inhalation rate, particle deposition and location of gas absorption in the respiratory tract are affected by the relative values of and , in addition to other factors such as fraction oral breathing (2).…”

Estimating the inhaled dose of pollutants during indoor physical activity

“…The solubility of the gaseous pollutants determines the absorption and the diffusion rates and particle size influence deposition fraction in the lungs (Bigazzi and Figliozzi, 2014). Smaller particles enhanced the deposition and hygroscopic aerosols will absorb water vapor from the lungs, thus growing in size and consequently changing their deposition properties (Winkler-Heil et al, 2014).…”

Variability of Black Carbon and Ultrafine Particle Concentration on Urban Bike Routes in a Mid-Sized City in the Po Valley (Northern Italy)

“…However, due to their proximity to the traffic source, cyclists might be exposed to higher concentrations of traffic-related atmospheric pollutants [4]. Some studies that directly compared the exposure concentrations, i.e., the concentrations to which a person is exposed, among different urban transport modes [5][6][7], reported contrasting results and highlighted the dependency of the exposure levels on a large number of variables, such as road characteristics and meteorological conditions [8][9][10][11][12]. However, most of the available evidence for urban cycling suggests that: (i) the higher the volume of motorized traffic the greater the cyclists' exposure to traffic-related pollutants, and in particular to ultrafine particles (UFPs, diameter smaller than 0.1 µm) and black carbon (BC); and (ii) bicycle paths that offer lateral separation between the cyclists and the motorized traffic reduce the concentration they are exposed to, as increased exposure concentrations are associated with increased proximity to traffic [13].…”