1346 / 2019-08-09 17:06:02

Characterizing PM2.5 exposures in public transport micro-environments in Hong Kong

3、环境科学 > 专题2：环境健康与安全风险评估

Public transport micro-environments (TMEs) include various transportation modes (e.g., buses) and facilities associated with boarding or alighting from a mode (e.g., bus stops). Exposure to PM2.5 in TMEs is often highly elevated. Field sampling campaigns were conducted to quantify PM2.5 exposure concentrations in several typical TMEs in Hong Kong, including Mass Transit Railway (MTR), minibus, double-decker bus, and tramcar (on-road). Linear regression equations between PM2.5 concentrations measured by a DustTrak aerosol monitor and by a United States Environmental Protection Agency (USEPA) benchmark method were used to bias correct PM2.5 measurements. The calibrated data was analyzed to understand the infiltration of ambient PM2.5 into the different TMEs. Key findings include: (1) TME PM2.5 exposure concentrations are sensitive to transportation mode, ventilation operation, and proximity to nearby emission sources; and (2) the in-cabin spatial variability of PM2.5 concentration was observed for MTR and double-decker bus mainly due to the change of ventilation conditions. The results should be helpful for more accurately estimate TME PM2.5 exposures and can be used to improve the study design of sampling campaigns to quantify infiltration of ambient PM2.5 into TMEs.