Davis M E, Blicharz A P, Hart J E, Laden F, Garshick E, Smith T J
Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, Massachusetts 02215, USA.
Environ Sci Technol. 2007 Oct 15;41(20):7152-8. doi: 10.1021/es071041z.
Diesel exhaust is a complex chemical mixture that has been linked to lung cancer mortality in a number of epidemiologic studies. However, the dose-response relationship remains largely undefined, and the specific components responsible for carcinogenicity have not been identified. Although previous focus has been on the particulate phase, diesel exhaust includes a vapor phase of numerous volatile organic compounds (VOCs) and aldehydes that are either known or suspected carcinogens, such as 1,3-butadiene, benzene, and formaldehyde. However, there are relatively few studies that quantify exposure to VOCs and aldehydes in diesel-heavy and other exhaust-related microenvironments. As part of a nationwide assessment of exposure to diesel exhaust in the trucking industry, we collected measurements of VOCs and aldehydes at 15 different U.S. trucking terminals and in city truck drivers (with 6 repeat site visits), observing average shift concentrations in truck cabs and at multiple background and work area locations within each terminal. In this paper, we characterize occupational exposure to 18 different VOCs and aldehydes, as well as relationships with particulate mass (elemental carbon in PM < 1 microm and PM2.5) across locations to determine source characteristics. Our results show that occupational exposure to VOCs and aldehydes varies significantly across the different sampling locations within each terminal, with significantly higher exposures noted in the work environments over background levels (p < 0.01). A structural equation model performed well in predicting terminal exposures to VOCs and aldehydes as a function of job, background levels, weather conditions, proximity to a major road, and geographic location (R2 = 0.2-0.4 work area; R2 = 0.5-0.9 background).
柴油尾气是一种复杂的化学混合物，在多项流行病学研究中已被证明与肺癌死亡率有关。然而，剂量反应关系在很大程度上仍不明确，且尚未确定导致致癌性的具体成分。尽管之前的研究重点是颗粒相，但柴油尾气还包括由众多挥发性有机化合物（VOCs）和醛类组成的气相，这些物质已知或疑似具有致癌性，如1,3 - 丁二烯、苯和甲醛。然而，相对较少的研究对柴油重度污染环境及其他与尾气相关的微环境中的VOCs和醛类暴露情况进行量化。作为对运输行业柴油尾气暴露情况进行的一项全国性评估的一部分，我们在美国15个不同的运输终点站以及城市卡车司机中（对6个重复站点进行了走访）收集了VOCs和醛类的测量数据，观察了卡车驾驶室以及每个终点站内多个背景和工作区域位置的平均轮班浓度。在本文中，我们描述了对18种不同VOCs和醛类的职业暴露情况，以及不同地点之间与颗粒物质量（PM < 1微米和PM2.5中的元素碳）的关系，以确定来源特征。我们的结果表明，每个终点站内不同采样地点的VOCs和醛类职业暴露差异显著，工作环境中的暴露水平明显高于背景水平（p < 0.01）。一个结构方程模型在预测终点站VOCs和醛类暴露情况方面表现良好，该暴露情况是工作、背景水平、天气条件、与主要道路的距离以及地理位置的函数（工作区域R2 = 0.2 - 0.4；背景区域R2 = 0.5 - 0.9）。
