| Summary: | 博士 === 國立陽明大學 === 環境與職業衛生研究所 === 105 === MRT station is one of the major public transports in the big city, and millions of passengers used MRT every day. Passengers may expose indoor air pollutants. Many studies have shown that the concentration of PM in the MRT station is higher than outdoor air, and its composition is different from outdoor. The aim of this study was to understand the distribution of air pollutants in the MRT station and analysis composition of PM. Furthermore, the MRT tunnel washing was evaluated for the removal of PM.
Using real time equipment measured the indoor air quality of the station. The components of PM were analyzed at the tunnel, platform and exit on MRT station. Finally, tunnel washing performance was evaluated within an MRT tunnel.
This study measured the indoor air quality of underground platforms at 10 metro stations of the Taipei Rapid Transit system (TRTS) in Taiwan, including humidity, temperature, carbon monoxide (CO), carbon dioxide (CO2), formaldehyde (HCHO), total volatile organic compounds (TVOCs),ozone (O3), airborne particulate matter (PM10 and PM2.5), bacteria and fungi. Results showed that the CO2, CO and HCHO levels met the stipulated standards as regulated by Taiwan’s Indoor Air Quality Management Act (TIAQMA). However, elevated PM10 and PM2.5 levels were measured at most stations. TVOCs and bacterial concentrations at some stations measured in summer were higher than the regulated standards stipulated by Taiwan’s Environmental Protection Administration. Further studies should be conducted to reduce particulate matters, TVOCs and bacteria in the air of subway stations.
Then this study, both PM10 and PM2.5 concentrations in Taipei Rapid Transit System (TRTS) decreased sequentially from the tunnels to the platforms to the entrances/exists, of which PM concentrations were still higher than those in ambient. The mainly metal components of the suspended particulates in TRTS were composed of Fe, Ba, Cu, Mn, Mg, Al, Cr, Zn, Ni and Pb. The Mn/Fe ratios in PM10 and PM2.5 were similar to the material specifications and composition of tracks, steel wheels and collector shoes as well as were from 0.012 to 0.020.
The monitoring results showed an increase in PM10 and PM2.5 concentrations after tunnel washing. The average concentrations of PM10 and PM2.5 during operation hours on the first day after tunnel washing increased by 144.9% and 152.9%, respectively, higher than those on the day before tunnel washing. The maximum increased concentrations were by 133.4% and 140.1% for PM10 and PM2.5, respectively. However, the average concentrations of PM10 and PM2.5 during operation hours on the second day after tunnel washing decreased by 81.2% and 79.3%, respectively, compared with those on the day before tunnel washing. The maximum decreased concentrations were by 67.2% and 67.0% for PM10 and PM2.5, respectively. In the long-term observation, the tunnel washing for PM10 was reduced by 45.9% than original concentrationand about 3.5 months as well as for PM2.5 was reduced by 71.3% about 2 months.
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