Linn W S, Shamoo D A, Avol E L, Whynot J D, Anderson K R, Venet T G, Hackney J D
Arch Environ Health. 1986 Sep-Oct;41(5):292-6. doi: 10.1080/00039896.1986.9936699.
Twenty-one mildly asthmatic volunteers were exposed to 0, 0.3, 1.0, and 3.0 ppm nitrogen dioxide (NO2) in purified background air in an environmental control chamber. Exposures were separated by 1-wk periods and occurred in random order. Each lasted 1 hr and included three 10-min bouts of moderately heavy exercise (mean ventilation rate 41 L/min). Exposure temperature was near 22 degrees C and relative humidity near 50%. Specific airway resistance and maximal forced expiratory performance were measured preexposure, after the initial exercise, and near the end of exposure. Bronchial reactivity was assessed immediately following exposure, by normocapnic hyperventilation with subfreezing air. Symptoms were recorded on questionnaires before, during, and for 1-wk after each exposure. Exercise induced significant bronchoconstriction regardless of NO2 level. No statistically significant untoward response to NO2 was observed at any exposure concentration. This negative finding agrees with our previous results, but contrasts with findings elsewhere of respiratory dysfunction after exposure to 0.3 ppm. The discrepancy is presently unexplained, but it may relate to different severity of asthma in different subject groups.
21名轻度哮喘志愿者在环境控制室的纯净背景空气中分别暴露于0、0.3、1.0和3.0 ppm的二氧化氮（NO₂）环境中。暴露之间间隔1周，且以随机顺序进行。每次暴露持续1小时，包括三次10分钟的中等强度运动（平均通气率41升/分钟）。暴露温度接近22摄氏度，相对湿度接近50%。在暴露前、初次运动后以及暴露接近结束时测量比气道阻力和最大用力呼气性能。暴露后立即通过用冷空气进行正常碳酸通气来评估支气管反应性。在每次暴露前、暴露期间以及暴露后1周内，通过问卷记录症状。无论NO₂水平如何，运动均会引起显著的支气管收缩。在任何暴露浓度下均未观察到对NO₂有统计学意义的不良反应。这一阴性结果与我们之前的结果一致，但与其他地方关于暴露于0.3 ppm后出现呼吸功能障碍的研究结果形成对比。目前尚无法解释这种差异，但可能与不同受试者组中哮喘的严重程度不同有关。
