Linn W S, Avol E L, Peng R C, Shamoo D A, Hackney J D
Environmental Health Service, Rancho Los Amigos Medical Center, University of Southern California, Downey 90242.
Am Rev Respir Dis. 1987 Nov;136(5):1127-34. doi: 10.1164/ajrccm/136.5.1127.
To help assess respiratory health risks from sulfur dioxide (SO2) air pollution, we studied 24 normal, 21 atopic, 16 minimal/mild asthmatic, and 24 moderate/severe, medication-dependent asthmatic subjects classified according to history, lung function, allergy skin tests, serum IgE level, and airway reactivity to methacholine. All were exposed in a chamber (21 degrees C, 50% humidity) to 0.0, 0.2, 0.4, and 0.6 ppm SO2 in random order at 1-wk intervals; then exposures were repeated to test consistency of response. The 1-h exposures included three 10-min exercise periods (ventilation approximately 40 L/min). Physiologic response was measured early (approximately 15 min) and late (approximately 55 min) in exposure. Symptoms were evaluated during exposure and for 1 wk afterward. Normal and most atopic subjects showed little response at these SO2 levels. A few atopic subjects and many asthmatics developed bronchoconstriction and respiratory symptoms, but most were able to maintain their exercise. Effects were not markedly different between early and late measurements, nor between the first and second round of studies; however, late and second-round responses appeared slightly more favorable. No statistically significant effect of SO2 on symptoms was found 1 day or 1 wk after exposure. Minimal/mild asthmatics showed, on the average, slight responses at 0.0 ppm (attributable to exercise) and increasing responses at increasing SO2 concentrations. Moderate/severe asthmatics reacted more at 0.0 ppm, but their increments in response with increasing SO2 concentration were roughly similar to those of minimal/mild asthmatics. Thus, responses to SO2 per se were not strongly dependent on clinical severity of asthma, nor on SO2 exposure history during previous weeks.
为了评估二氧化硫（SO₂）空气污染对呼吸健康的风险，我们研究了24名正常受试者、21名特应性受试者、16名轻度/轻度哮喘患者以及24名中度/重度、依赖药物治疗的哮喘患者，这些受试者根据病史、肺功能、过敏皮肤试验、血清IgE水平以及对乙酰甲胆碱的气道反应性进行分类。所有人均在一个舱室（21摄氏度，湿度50%）中，以随机顺序每隔1周暴露于0.0、0.2、0.4和0.6 ppm的SO₂环境中；然后重复暴露以测试反应的一致性。1小时的暴露包括三个10分钟的运动时段（通气量约为40升/分钟）。在暴露早期（约15分钟）和晚期（约55分钟）测量生理反应。在暴露期间以及之后的1周内评估症状。正常受试者和大多数特应性受试者在这些SO₂水平下几乎没有反应。一些特应性受试者和许多哮喘患者出现了支气管收缩和呼吸道症状，但大多数人仍能维持运动。早期和晚期测量之间以及第一轮和第二轮研究之间的影响没有明显差异；然而，晚期和第二轮反应似乎略为有利。暴露后1天或1周，未发现SO₂对症状有统计学上的显著影响。轻度/轻度哮喘患者平均在0.0 ppm时显示出轻微反应（归因于运动），并随着SO₂浓度增加而反应增强。中度/重度哮喘患者在0.0 ppm时反应更强，但随着SO₂浓度增加其反应增量与轻度/轻度哮喘患者大致相似。因此，对SO₂本身的反应并不强烈依赖于哮喘的临床严重程度，也不依赖于前几周的SO₂暴露史。
