AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Characteristics of Personal Exposure to PM2.5 in Public Transportations in Beijing, China
CAIQING YAN, Mei Zheng, Qiaoyun Yang, Qunfang Zhang, Xinghua Qiu, Tong Zhu, Yifang Zhu, Peking University
Abstract Number: 657 Working Group: Aerosol Exposure
Abstract People living in megacities in China such as Beijing are exposed to higher levels of air pollutants due to large and dense population, diversified transportation modes, and longer exposure to roadway and railway emissions. This study examined pedestrians and commuters’ exposure to fine particulate matter (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) in different transportation modes including walking, taking subway and riding bus during two weeks of December 2011 in Beijing. Concentrations of PM2.5, particle number as well as PAHs were measured by DustTrak, CPC, and offline GC-MS, respectively. The results revealed particulate matter exposure level, including mass concentration and particle number, in Beijing subway was the highest. PM2.5 exposure levels in roadway transportation (including walking and riding bus) exhibited clear diurnal variation with higher level during commuting rush hours and lower at noon. However, particle number concentrations showed an opposite trend, peaking at noon but lower at rush hours. Particulate PAHs concentrations were about 2.5 times higher in roadway environment than subway system, and up to 17 times higher in polluted days with high ambient PM2.5 concentration compared to clean days. The results indicated that walking pedestrians were more susceptible to higher risks (about 1.3-3.4 times) than people using other commuting methods based on calculated benzo[a]pyrene toxic equivalents (BaP TEQs). Although subway commuters were exposed to the highest particulate matter exposure level, their BaP TEQs levels were lower than waling pedestrians. Some characteristic sources in China, such as roadside restaurants and barbecuing as well as smoking, were also strong sources for sudden and significant increase of particle number experienced by pedestrians.
Keywords: fine particulate matter, PAHs, transportation exposure, subway, bus, walking.