Short-term exposure to PM10, PM2.5, ultrafine particles and CO2 for passengers at an intercity bus terminal

The Taipei Bus Station is the main transportation hub for over 50 bus routes to eastern, central, and southern Taiwan. Daily traffic volume at this station is about 2500 vehicles, serving over 45,000 passengers daily. The station is a massive 24-story building housing a bus terminal, a business hotel, a shopping mall, several cinemas, offices, private residential suites, and over 900 parking spaces. However, air quality inside this bus terminal is a concern as over 2500 buses are scheduled to run daily. This study investigates the PM10, PM2.5, UFP and CO2 levels inside and outside the bus terminal. All measurements were taken between February and April 2010. Measurement results show that coarse PM inside the bus terminal was resuspended by the movement of large numbers of passengers. The fine and ultrafine PM in the station concourse were from outside vehicles. Moreover, fine and ultrafine PM at waiting areas were exhausted directly from buses in the building. The CO2 levels at waiting areas were likely elevated by bus exhaust and passengers exhaling. The PM10, PM2.5 and CO2 levels at the bus terminal were lower than Taiwan's EPA suggested standards for indoor air quality. However, UFP levels at the bus terminal were significantly higher than those in the urban background by about 10 times. Therefore, the effects of UFPs on the health of passengers and workers must be addressed at this bus terminal since the levels of UFPs are higher than > 1.0 x 10(5) particles cm(-3). (C) 2011 Elsevier Ltd. All rights reserved.