The monitoring of human exposures to diesel exhaust continues to be a vexing problem for specialists seeking information on the potential health effects of this ubiquitous combustion product. Exposure biomarkers have yielded a potential solution to this problem by providing a direct measure of an individual's contact with key components in the exhaust stream. Spurred by the advent of new, highly sensitive, analytical methods capable of detecting substances at very low levels, there have been numerous attempts at identifying a stable and specific biomarker. Despite these new techniques, there is currently no foolproof method for unambiguously separating diesel exhaust exposures from those arising from other combustion sources. Diesel exhaust is a highly complex mixture of solid, liquid, and gaseous components whose exact composition can be affected by many variables, including engine technology, fuel composition, operating conditions, and photochemical aging. These factors together with those related to exposure methodology, epidemiological necessity, and regulatory reform can have a decided impact on the success or failure of future research aimed at identifying a suitable biomarker of exposure. The objective of this review is to examine existing information on exposure biomarkers for diesel exhaust and to identify those factors and trends that have had an impact on the successful identification of metrics for both occupational and community settings. The information will provide interested parties with a template for more thoroughly understanding those factors affecting diesel exhaust emissions and for identifying those substances and research approaches holding the greatest promise for future success.

中文翻译：

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影响柴油机尾气暴露可靠生物标志物鉴定的因素和趋势

对于寻求有关这种无处不在的燃烧产物的潜在健康影响的信息的专家来说，监测人体接触柴油机尾气的情况仍然是一个棘手的问题。暴露生物标志物通过直接测量个人与废气流中关键成分的接触，为这个问题提供了一个潜在的解决方案。在能够检测极低水平物质的新的、高度灵敏的分析方法的出现的推动下，已经有许多尝试来确定稳定和特异性的生物标志物。尽管有这些新技术，目前还没有万无一失的方法可以明确地将柴油机尾气暴露与其他燃烧源产生的暴露区分开来。柴油机尾气是一种高度复杂的固体、液体混合物，和气体成分，其确切成分会受到许多变量的影响，包括发动机技术、燃料成分、操作条件和光化学老化。这些因素连同与暴露方法、流行病学必要性和监管改革相关的因素，会对未来旨在确定合适的暴露生物标志物的研究的成败产生决定性影响。本次审查的目的是检查有关柴油机尾气暴露生物标志物的现有信息，并确定那些对成功确定职业和社区环境指标产生影响的因素和趋势。