Chronic obstructive pulmonary disease (COPD) is not a single disease, but rather a category of several diseases, such as chronic bronchitis and emphysema, that impede air from getting to the lungs. It is a progressive, chronic condition, which means that it gets worse over time. There are various causes of this illness, including smoking and long term exposure to airborne pollutants. The inhaler for COPD is the most common form of treatment, mainly because it is such an effective way of delivering the medication.