Commuter exposure to ultrafine particles in different urban locations, transportation modes and routes

• Published in: Atmospheric environment (1994) 2013-10, Vol.77, p.376-384
• Main Authors: Ragettli, Martina S., Corradi, Elisabetta, Braun-Fahrländer, Charlotte, Schindler, Christian, de Nazelle, Audrey, Jerrett, Michael, Ducret-Stich, Regina E., Künzli, Nino, Phuleria, Harish C.
• Format: Article
• Language: English
• Subjects: Air pollution; Air. Soil. Water. Waste. Feeding; Applied sciences; Atmospheric pollution; Biological and medical sciences; Commuter; Environment. Living conditions; Exact sciences and technology; Medical sciences; Near-road exposure; Particle size; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Public health. Hygiene; Public health. Hygiene-occupational medicine; Switzerland; Ultrafine particles
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2013.05.003

A better understanding of ultrafine particle (UFP) exposure in different urban transport microenvironments is important for epidemiological exposure assessments and for policy making. Three sub-studies were performed to characterize personal exposure to UFP concentration and average particle size distribution diameters in frequently traveled commuter microenvironments in the city of Basel, Switzerland. First, the spatial variation of sidewalk UFP exposures within urban areas and transport-specific microenvironments was explored. Second, exposure to UFP concentration and average particle size were quantified for five modes of transportation (walking, bicycle, bus, tram, car) during different times of the day and week, along the same route. Finally, the contribution of bicycle commuting along two different routes (along main roads, away from main roads) to total daily exposures was assessed by 24-h personal measurements. In general, smaller average particle sizes and higher UFP levels were measured at places and for travel modes in close proximity to traffic. Average trip UFP concentrations were higher in car (31,784 particles cm−³) and on bicycle (22,660 particles cm−³) compared to walking (19,481 particles cm−³) and public transportation (14,055–18,818 particles cm−³). Concentrations were highest for all travel modes during weekday morning rush hours, compared to other time periods. UFP concentration was lowest in bus, regardless of time period. Bicycle travel along main streets between home and work place (24 min on average) contributed 21% and 5% to total daily UFP exposure in winter and summer, respectively. Contribution of bicycle commutes to total daily UFP exposure could be reduced by half if main roads are avoided. Our results show the importance of considering commuter behavior and route choice in exposure assessment studies. •UFP concentration and mean particle size were measured in transport environments.•Personal sampling included urban areas, five travel modes and two bicycle routes.•Highest UFP concentrations were measured in car and on bicycle, lowest in bus.•Bicycle commutes contributed notably (21% in winter) to 24-h UFP exposure.•Avoiding main roads reduced the contribution of bicycle commutes to total daily UFP.