Fiedler N, Kelly-McNeil K, Mohr S, Lehrer P, Opiekun R E, Lee C, Wainman T, Hamer R, Weisel C, Edelberg R, Lioy P J
UMDNJ-Robert Wood Johnson Medical School, Department of Environmental and Community Medicine, Piscataway, New Jersey 08854, USA.
Environ Health Perspect. 2000 Aug;108(8):753-63. doi: 10.1289/ehp.00108753.
The 1990 Clean Air Act mandated oxygenation of gasoline in regions where carbon monoxide standards were not met. To achieve this standard, methyl tertiary butyl ether (MTBE) was increased to 15% by volume during winter months in many locations. Subsequent to the increase of MTBE in gasoline, commuters reported increases in symptoms such as headache, nausea, and eye, nose, and throat irritation. The present study compared 12 individuals selected based on self-report of symptoms (self-reported sensitives; SRSs) associated with MTBE to 19 controls without self-reported sensitivities. In a double-blind, repeated measures, controlled exposure, subjects were exposed for 15 min to clean air, gasoline, gasoline with 11% MTBE, and gasoline with 15% MTBE. Symptoms, odor ratings, neurobehavioral performance on a task of driving simulation, and psychophysiologic responses (heart and respiration rate, end-tidal CO(2), finger pulse volume, electromyograph, finger temperature) were measured before, during, and immediately after exposure. Relative to controls, SRSs reported significantly more total symptoms when exposed to gasoline with 15% MTBE than when exposed to gasoline with 11% MTBE or to clean air. However, these differences in symptoms were not accompanied by significant differences in neurobehavioral performance or psychophysiologic responses. No significant differences in symptoms or neurobehavioral or psychophysiologic responses were observed when exposure to gasoline with 11% MTBE was compared to clean air or to gasoline. Thus, the present study, although showing increased total symptoms among SRSs when exposed to gasoline with 15% MTBE, did not support a dose-response relationship for MTBE exposure nor the symptom specificity associated with MTBE in epidemiologic studies.
1990年的《清洁空气法》规定，在未达一氧化碳标准的地区，需对汽油进行加氧处理。为达到这一标准，许多地方在冬季将甲基叔丁基醚（MTBE）的添加量提高至15%（体积比）。汽油中MTBE添加量增加后，通勤者报告出现了诸如头痛、恶心以及眼睛、鼻子和喉咙不适等症状。本研究将12名根据与MTBE相关的自我症状报告（自我报告敏感者；SRSs）选出的个体，与19名无自我报告敏感症状的对照者进行了比较。在一项双盲、重复测量、对照暴露实验中，受试者分别暴露于清洁空气、汽油、含11% MTBE的汽油以及含15% MTBE的汽油中15分钟。在暴露前、暴露期间和暴露后，分别测量了症状、气味评级、驾驶模拟任务中的神经行为表现以及心理生理反应（心率、呼吸频率、呼气末二氧化碳、手指脉搏容积、肌电图、手指温度）。与对照者相比，SRSs在暴露于含15% MTBE的汽油时报告的总症状显著多于暴露于含11% MTBE的汽油或清洁空气时。然而，这些症状差异并未伴随神经行为表现或心理生理反应的显著差异。当将含11% MTBE的汽油暴露与清洁空气或汽油暴露进行比较时，未观察到症状、神经行为或心理生理反应的显著差异。因此，本研究虽然表明SRSs在暴露于含15% MTBE的汽油时总症状有所增加，但并不支持MTBE暴露的剂量反应关系，也不支持流行病学研究中与MTBE相关的症状特异性。
