Tollbooth Workers and Mobile Source-Related Hazardous Air Pollutants: How Protective Is the Indoor Environment?
详细信息 查看全文
- 作者：Amir Sapkota ; D'Ann Williams ; and Timothy J. Buckley
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：May 1, 2005
- 年：2005
- 卷：39
- 期：9
- 页码：2936 - 2943
- 全文大小：236K
- 年卷期：v.39,no.9(May 1, 2005)
- ISSN：1520-5851
文摘
Tollbooth workers are potentially exposed to high levelsof mobile source-related air pollutants due to the proximityand intensity of the source. To evaluate this workerhazard, we measured the concentration of air toxinsincluding volatile organic compounds (VOCs) and particle-bound polycyclic aromatic hydrocarbons (PAHs) insideand outside a Baltimore Harbor Tunnel tollbooth during thesummer of 2001. Mean outdoor benzene and1,3-butadiene concentrations varied by shift with themorning (10.7 and 19.8 
g/m3) exceeding afternoon (7.2and 14.9 g/m3) and the lowest levels observed during thenight (3.7 and 4.9 g/m3, respectively) when trafficvolume was the lowest. In comparison, considerableprotection was provided to workers by the indoor environmentwhere lower concentrations of 1,3-butadiene and benzenewere observed for all three shifts (2.9 and 6.7, 0.9 and3.2, and 0.9 and 2.4 g/m3, respectively). The greatestprotection offered by the tollbooth was observed duringthe afternoon shift (5-8-fold reduction in indoor concentration), whereas the morning and night shifts experiencedsimilar protection (2-4-fold reduction). Chlorinatedhydrocarbons were observed at higher concentrationswithin the tollbooth, indicating the presence of indoor sourcesand the opportunity for exposure mitigation. Levels ofPAHs were similarly reduced from outdoors (50 ng/m3) toindoors (15.4 ng/m3). The protective nature of the tollboothhighlighted in this study is likely due to the positive pressurecontrol ventilation system that was present at thisspecific facility, which represents 55% of tollbooths inMaryland. This study provides an estimate of tollboothworkers potential exposures to various mobile source-related pollutants and highlights the protective nature oftollbooths equipped with positive pressure control ventilationsystems.
g/m3) exceeding afternoon (7.2and 14.9 g/m3) and the lowest levels observed during thenight (3.7 and 4.9 g/m3, respectively) when trafficvolume was the lowest. In comparison, considerableprotection was provided to workers by the indoor environmentwhere lower concentrations of 1,3-butadiene and benzenewere observed for all three shifts (2.9 and 6.7, 0.9 and3.2, and 0.9 and 2.4 g/m3, respectively). The greatestprotection offered by the tollbooth was observed duringthe afternoon shift (5-8-fold reduction in indoor concentration), whereas the morning and night shifts experiencedsimilar protection (2-4-fold reduction). Chlorinatedhydrocarbons were observed at higher concentrationswithin the tollbooth, indicating the presence of indoor sourcesand the opportunity for exposure mitigation. Levels ofPAHs were similarly reduced from outdoors (50 ng/m3) toindoors (15.4 ng/m3). The protective nature of the tollboothhighlighted in this study is likely due to the positive pressurecontrol ventilation system that was present at thisspecific facility, which represents 55% of tollbooths inMaryland. This study provides an estimate of tollboothworkers potential exposures to various mobile source-related pollutants and highlights the protective nature oftollbooths equipped with positive pressure control ventilationsystems.