人体的呼吸道与外界环境中的空气要进行气体交换,即机体代谢需要的氧气必须从外界吸入,代谢的产物二氧化碳要随时排出体外,这是维持人体生存不可缺少、不能间断的生理活动。由于呼吸道经常会与空气中的各种细菌、霉菌、致敏原、烟雾、灰尘等接触,呼吸道还会受气候变化等因素的影响,因此容易受到损害。 The human body’s respiratory tract and the atmosphere in the environment to exchange gas, that is, the body needs oxygen from the outside inhalation, the metabolic products of carbon dioxide to be discharged at any time, which is indispensable to maintain human life, can not be interrupted physical activity. As the respiratory tract often with various bacteria in the air, mold, allergens, smoke, dust and other contact, the respiratory tract will be affected by climate change and other factors, and therefore vulnerable to damage.