在有损于人体健康的生产环境中,为了防止酸雾、毒气及粉尘等的危害,人们使用了多种型式的防毒面具。这类防毒面具的结构都设有密封性能良好的面罩、防尘过滤器、导气软管、压缩空气过滤器及固定元件等。但它们都以密封的面罩或半面罩形式,全部罩住并紧贴呼吸器官和视觉器官,使 In the detrimental to human health production environment, in order to prevent the hazards of acid mist, gas and dust, people use a variety of types of gas masks. The structure of such gas masks are equipped with a good sealing performance mask, dust filter, air hose, compressed air filters and fixed components. But they are all in the form of a sealed mask or half-mask, all covering and in close proximity to the respiratory and visual organs