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

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• 作者：Martina S. Ragettli ; Elisabetta Corradi ; Charlotte Braun-Fahrl?nder ; Christian Schindler ; Audrey de Nazelle ; Michael Jerrett ; Regina E. Ducret-Stich ; Nino K¨¹nzli ; Harish C. Phuleria
• 关键词：Air pollution ; Ultrafine particles ; Commuter ; Near-road exposure ; Particle size ; Switzerland
• 刊名：Atmospheric Environment
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：77
• 期：Complete
• 页码：376-384
• 全文大小：2106 K

文摘

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.