Cycle paths can be used as a route for active transportation or simply to cycle for physical activity and leisure. However, exposure to air pollutants can be boosted while cycling, in urban environments, due to the proximity to vehicular emissions and elevated breathing rates. The objective of this work was to assess the exposure of a cyclist to particles and to chemical elements by combining real-time aerosol mass concentration reading equipment and biomonitoring techniques. PM₁₀ and PM_2.5 were measured on three cycle paths located in Lisbon, during weekdays and weekends and during rush hours and off-peak hours resulting in a total of 60 campaigns. Lichens were exposed along cycle paths for 3 months, and their element contents were measured by instrumental neutron activation analysis using the k₀ methodology (k₀-INAA). Using a bicycle commute route of lower traffic intensity and avoiding rush hours or other times with elevated vehicular congestion facilitate a reduction in exposure to pollutants. The implementation of cycle paths in cities is important to stimulate physical activity and active transportation; however, it is essential to consider ambient air and pollutant sources to create safer infrastructures.

Active commuting has great health, environment, economic, and social benefits. However, cyclists are at risk for exposure to vehicle-related air pollutants due to their proximity to vehicle traffic and elevated respiratory rates. Consequently, more information on differences in inhaled doses between different transport modes is needed. The aim of this study is to assess and map the exposure of travelers to air pollutants using different transportation modes and to consider minute ventilation variablity and travel duration for the calculation of inhaled dose. Particulate matter (PM10, PM4, PM2.5 and PM1), CO, volatile organic compound (VOC), CO₂, and O₃ were measured between December 2013 and March 2014 in a total of 75 travels performed by bus, metro, car, bicycle, and motorcycle at five periods of the day (8, 11, 14, 17:30, and 21 h). Results showed that car drivers and bus passengers in urban streets may be exposed to higher pollutant levels than cyclists traveling in the same streets. However, this enhanced air pollution exposure is compensated by the higher ventilation rates of cyclists, which presented the highest inhaled doses. To reduce exposure concentrations, spatial and temporal separation of cyclists from motorized vehicle traffic should be achieved with separated bicycle facilities, low volume routes, and off-peak travel.