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臭氧是光化学烟雾中主要的氧化物,它可增强健康者和哮喘患者的支气管反应性。作者研究低浓度臭氧能否增强特应性哮喘患者气道对过敏原的反应性。轻症特应性哮喘患者7例,6例为非吸烟者,1例已戒烟,平均年龄40±13岁,有哮喘季节发作史,豚草或牧草皮肤试验阳性。乙酰甲胆碱激发试验浓度为使FEV_1下降20％(PC20)或40％的肺活量下降40％(PC40V40p)。过敏原激发试验浓度为使FEV_1下降15％(PC15)。12天的实验分4个阶段,每阶段3天,第1、3天作乙酰甲胆碱试验,第2天行单盲联合试验。对照组吸入空气1h接着吸入过敏原稀释液;过敏原组吸入空气1h接着吸入过敏原;臭氧组吸入臭氧1h接着吸入过敏原稀释液;臭氧或过敏原组吸入臭氧1h接着吸入过敏原。吸入的臭氧浓度保持在0.12±0.02ppm。每次吸入成倍浓度的过敏原2min,吸入后10min测定FEV_1,至FEV_1下降15％以上为止。观察时实验室内臭氧平均浓度0.006～0.008ppm,
Ozone is a major oxide in photochemical smog that enhances bronchial reactivity in both healthy and asthmatic patients. The authors investigated whether low concentrations of ozone could enhance airway responsiveness to allergens in patients with atopic asthma. Seven patients with mild atopic asthma, six non-smokers, one patient who had quit smoking, with an average age of 40 ± 13 years, had a history of asthma seizures and a positive ragweed or pasture skin test. The methacholine challenge test concentration was a 40% reduction in the vital capacity (PC40V40p) for a 20% decrease in FEVl (PC20) or 40%. The concentration of allergen challenge test was 15% reduction in FEV 1 (PC15). The 12-day experiment was divided into 4 stages, with 3 days in each stage, methacholine test on the first and third days, and single blind combination test on the second day. The control group inhaled air 1h and then inhaled allergen diluent; inhaled air allergen group 1h then inhaled allergens; ozone group inhaled ozone 1h then inhaled allergen diluent; ozone or allergen group inhaled ozone 1h then inhaled allergens. Inhaled ozone concentration was maintained at 0.12 ± 0.02ppm. Each inhalation of doubled concentration of allergens 2min, 10min after inhalation measured FEV_1, to FEV_1 decreased by 15% or so far. Observed when the average ozone concentration in the laboratory 0.006 ~ 0.008ppm,