Research Portal

July 1, 2022

Measuring Pedestrian Exposure to PM-2.5: Case of the Seattle, Washington, International District

Bae, Chang-hee Christine; Sinha, Debmalya. (2016). Measuring Pedestrian Exposure to PM-2.5: Case of the Seattle, Washington, International District. Transportation Research Record, 2570, 139 – 147.

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Traffic-related air pollution is dangerous to human health. Although transportation and land use planning policies often focus on making walking more attractive, there is a lack of research on pedestrian exposure to air pollution levels. This research focused on pedestrian exposure to particulate matter with a diameter of 2.5 mu m or less (PM-2.5) in the International District (ID) adjacent to downtown Seattle, Washington. Several types of equipment were used: (a) a portable nephelometer (Radiance Research M903) mounted on a backpack (arranged by the Puget Sound Clean Air Agency); (b) an AirCasting mobile application (by Habitmap) in a cell phone to record the researcher's location and exposure levels while walking; and (c) a GoPro Hero camera to record visual images of the surrounding built environment, traffic volume, and other activities. The field data were collected three times a day (morning, midday, and evening) for one week in winter (December 31, 2014-January 9, 2015) and one week in spring (March 21-30, 2015) on selected routes in the ID. The study found seasonal and time-of-day variability of exposure levels: there were higher PM-2.5 concentration levels during the winter (57.77 mu g/m(3)) than in the spring (6.99 mu g/m(3)), and higher levels in the morning (25 mu g/m(3)) than in the evening (17 mu g/m(3)). Also, the average PM-2.5 levels of ID data were slightly higher (20.7 mu g/m(3)) than those at the nearest U.S. Environmental Protection Agency monitoring station (19.0 mu g/m(3)). The researchers concluded that the key contributors of pedestrian exposure to air pollution are traffic, construction activities, and smokers on sidewalks.


Particulate Air-pollution; Long-term Exposure; Particle Number; Fine; Quality; Health; Pm2.5; Risk; Road