Concentrations of ultrafine particles at a highway toll collection booth and exposure implications for toll collectors.
Research regarding the magnitude of ultrafine particle levels at highway toll stations is limited. This study measured ambient concentrations of ultrafine particles at a highway toll station from October 30 to November 1 and November 5 to November 6, 2008. A scanning mobility particle sizer was used to measure ultrafine particle concentrations at a ticket/cash tollbooth. Levels of hourly average ultrafine particles at the tollbooth were about 3-6 times higher than those in urban backgrounds, indicating that a considerable amount of ultrafine particles are exhausted from passing vehicles. A bi-modal size distribution pattern with a dominant mode at about <6 nm and a minor mode at about 40 nm was observed at the tollbooth. The high amounts of nanoparticles in this study can be attributed to gas-to-particle reactions in fresh fumes emitted directly from vehicles. The influences of traffic volume, wind speed, and relative humidity on ultrafine particle concentrations were also determined. High ambient concentrations of ultrafine particles existed under low wind speed, low relative humidity, and high traffic volume. Although different factors account for high ambient concentrations of ultrafine particles at the tollbooth, measurements indicate that toll collectors who work close to traffic emission sources have a high exposure risk.
Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, 84 Gungjuan Rd, Taishan, Taipei 24301, Taiwan. yhcheng@mail.mcut.edu.tw
Yu-Hsiang
YH
Cheng
Cheng-Hsiung
CH
Huang
Hsiao-Lin
HL
Huang
Chuen-Jinn
CJ
Tsai
D000393:Air Pollutants / Q000032:analysis*; D000395:Air Pollutants, Occupational / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D008685:Meteorological Concepts; D016273:Occupational Exposure / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D014186:Transportation
D000393:Air Pollutants; D000395:Air Pollutants, Occupational; D052638:Particulate Matter