Kleinman M T, Mautz W J
Air Pollution Health Effects Laboratory, University of California, Irvine 92717.
Res Rep Health Eff Inst. 1991 Oct(45):1-40; discussion 41-50.
The purpose of this study was to determine how changes in ventilation rate and in the entry route of air pollutants into the respiratory tract (nose versus mouth breathing) affected the respiratory tract uptake and penetration of inhaled gaseous and particulate pollutants associated with automobile emissions. Experiments were performed with female beagle dogs exposed while standing at rest or while exercising on a treadmill at 5 km/hour and a 7.5 percent grade. Dogs were exposed to nitrogen dioxide at concentrations of 1 and 5 parts per million (ppm), to formaldehyde at 2 and 10 ppm, and to an aerosol of ammonium nitrate particles (0.3 micron mass median aerodynamic diameter) at 1 mg/m3. Total respiratory system uptake and effects on breath time, expired tidal volume, fractional expiration time, minute ventilation, respiratory gas exchange, ventilation equivalents for oxygen and carbon dioxide, and dynamic pulmonary resistance and compliance were measured in exercising and resting dogs exposed for two hours to 5 ppm nitrogen dioxide and 10 ppm formaldehyde in combination with 1 mg/m3 of ammonium nitrate particles. Regional penetration of pollutants through oral and nasal airways and pollutant uptake in the lung were measured in a separate group of six tracheostomized dogs standing at rest while being exposed to nitrogen dioxide, formaldehyde, and ammonium nitrate particles. Hypercapnic stimulation was used to modify ventilation rates in the tracheostomized dogs while pollutant penetration and uptake were measured. Dogs exposed to 5 ppm of nitrogen dioxide at rest tended to breathe more rapidly (p less than 0.05) and more shallowly (a nonsignificant trend) than dogs exposed to purified air. The changes observed were similar in direction, but of smaller magnitude, to changes observed when the same dogs were exposed during exercise to ozone at 0.6 ppm in a separate study. Rapid-shallow breathing was not observed when the dogs were exposed during exercise to 5 ppm nitrogen dioxide. Dogs exposed to a mixture of 10 ppm formaldehyde and 1 mg/m3 ammonium nitrate particles during exercise showed a shift to larger tidal volume breathing, but the response was much less pronounced than the slow-deep breathing pattern response observed in a separate study of dogs exposed to 10 ppm formaldehyde alone. The total respiratory system uptake of formaldehyde from the formaldehyde and ammonium nitrate mixture was larger than that measured for 10 ppm of formaldehyde alone in another exercise and exposure study.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究的目的是确定通气率的变化以及空气污染物进入呼吸道的途径（经鼻呼吸与经口呼吸）如何影响与汽车排放相关的吸入气态和颗粒污染物在呼吸道的摄取和穿透。实验在雌性比格犬身上进行，这些犬在静止站立或在跑步机上以5公里/小时的速度、7.5%的坡度运动时接受暴露。犬分别暴露于浓度为百万分之一（ppm）的1和5的二氧化氮、2和10 ppm的甲醛以及浓度为1毫克/立方米的硝酸铵颗粒气溶胶（质量中位空气动力学直径为0.3微米）。在暴露于5 ppm二氧化氮和10 ppm甲醛并伴有1毫克/立方米硝酸铵颗粒两小时的运动和静止的犬中，测量了整个呼吸系统的摄取以及对呼吸时间、呼出潮气量、呼气分数时间、分钟通气量、呼吸气体交换、氧和二氧化碳的通气当量以及动态肺阻力和顺应性的影响。在另一组六只气管切开的犬静止站立并暴露于二氧化氮、甲醛和硝酸铵颗粒时，测量了污染物通过口腔和鼻腔气道的区域穿透以及在肺中的污染物摄取。在测量污染物穿透和摄取时，对气管切开的犬使用高碳酸血症刺激来改变通气率。与暴露于净化空气的犬相比，静止时暴露于5 ppm二氧化氮的犬往往呼吸更快（p小于0.05）且更浅（一种无显著意义的趋势）。观察到的变化方向相似，但幅度较小，与在另一项单独研究中这些犬在运动时暴露于0.6 ppm臭氧时观察到的变化相似。当犬在运动时暴露于5 ppm二氧化氮时，未观察到快速浅呼吸。运动时暴露于10 ppm甲醛和1毫克/立方米硝酸铵颗粒混合物的犬表现出向更大潮气量呼吸的转变，但该反应远不如在另一项单独研究中暴露于10 ppm单独甲醛的犬所观察到的慢深呼吸模式反应明显。在另一项运动和暴露研究中，从甲醛和硝酸铵混合物中摄取的甲醛总量大于单独测量的10 ppm甲醛的摄取量。（摘要截短至400字）
