Comparison of Commuter Exposure to Particulate Matters and Carbon Monoxide by Four Transportation Tools in Taipei City

Abstract

MS7-02 Introduction: This study examined in-vehicle concentration and commuter exposures of particulate matter (PM) and carbon monoxide (CO) in 4 transportation modes: bus, car, motorcycle, and mass rapid transit (MRT). Methods: Personal exposures to air pollutants (PM1.0, PM1.0–2.5, PM2.5–10, PM10, and CO) were simultaneously measured in 4 means of transportation on 4 routes during the morning and evening rush hours during weekdays from January to April 2005 in Taipei. GRIMM Dust Monitors and Draeger Miniwarn were, respectively, used to record PM concentrations with 4 size ranges and CO every minute. We used video or logbooks to record unusual events such as bus door open time, idle time at a traffic light for car and motorcycle commuters, and walking periods for MRT commuter, which could influence PM and CO concentrations. We then calculated commuters’ yearly inhaled doses of PM and CO by combining in-vehicle concentrations, commuting time, and commuters’ ventilation rate. Results: The in-vehicle mass concentration of PM1.0, PM1.0–2.5, PM2.5–10, and PM10 was highest in motorcycle followed by bus, MRT, and car. The in-vehicle concentrations of PM1.0 in motorcycle, bus, MRT, and car were 39.5 μg/m3, 28.5 μg/m3, 24.9 μg/m3, and 18.3 μg/m3. For car drivers, the concentrations of PM and CO showed little variation, even during unusual events. For motorcycle riders, the concentrations of PM and CO were higher while stopping at traffic lights than while moving. For MRT commuters, the concentrations of PM and CO were higher while walking outdoors than while riding the MRT. Adult commuters’ annual PM1.0 doses were 10.3 mg by motorcycle, 7.4 mg by bus, 3.9 mg by MRT, and 5.7 mg by car. Their annual CO doses were 2.3 g by motorcycle, 1.1 g by bus, 0.1 g by MRT, and 5.4 g by car. Discussion and Conclusion: Motorcyclists have higher PM and CO exposures than private car drivers and public transportation riders while commuting in Taipei. The vehicle exhausts seem to be the main sources of commuters’ exposure to PM and CO in Taipei.