So how do they work? When you take a breath, air travels through your lungs using tubes called airways, or bronchi. The airways funnel to sacs, called alveoli, where your red blood cells absorb all the oxygen your body needs.那么，它们是如何起作用的呢？当你吸气时，空气通过称为气道或支气管的管道进入肺部。气道最终通向被称为肺泡的气囊，红血球就在这里吸收身体所需的全部氧气。

But if you have asthma, the muscles around your airways may tighten, the lining of your airways may get inflamed, and your lungs may make too much of the mucus they use to trap dust and germs. Essentially, this clogs the pipes and makes it difficult to exhale.但如果你患有哮喘，气道周围的肌肉可能会收缩，气道内壁可能发炎，而肺部可能会产生过多的黏液——这种黏液原本用于捕捉灰尘和病菌。结果就像管道被堵住一样，使呼气变得困难。

Rescue inhalers deliver a medication called a bronchodilator that quickly relaxes these muscles, making it easier to breathe. These bronchodilators are short acting, lasting around four hours.急救型吸入器会输送一种名为“支气管扩张剂”的药物，它能迅速放松这些肌肉，使呼吸变得顺畅。这类支气管扩张剂属于短效药物，作用时间大约为四小时。

Rescue inhalers can be used for COPD, too. COPD is a catch-all term to describe the most common breathing conditions, like emphysema and chronic bronchitis, which people often have at the same time.急救型吸入器同样可以用于治疗慢性阻塞性肺病（COPD）。COPD 是一个总称，用来描述最常见的呼吸系统疾病，如肺气肿和慢性支气管炎，这两种疾病往往会同时出现。

In emphysema, repeated exposure to smoke or irritating particles breaks the inner walls of the alveoli. Because there's less surface area for blood and oxygen to interact, less oxygen makes its way to your bloodstream, causing you to constantly feel out of breath.在肺气肿中，长期接触烟雾或刺激性颗粒会破坏肺泡的内壁。由于血液与氧气交换的表面积减少，进入血液的氧气也随之减少，因此患者会持续感到呼吸困难。