Chronic obstructive pulmonary disease, or COPD for short, will be 3rd biggest killer in the world by 2020. The major cause of this disease is cigarette smoking, but only about 15-20% of smokers will develop COPD. In this disease, the lung becomes damaged and patients can not breathe properly. This damage can not be repaired therefore at the moment there are no good treatements for COPD. By the time a patient visits their doctor with symptoms the damage is already done. Therefore in this study we want to look at the lungs of smokers that feel well and can breathe normally. We believe that much of the damage to the lung in COPD is caused by inflammation. In particular, there are more inflammatory cells called macrophages in the lungs of these patients. These macrophages normally protect the lung when we inhale particles like dust and are also inportant to fight infections. In COPD, these macrophages are out of control and produce huge amounts of enzymes that break down lung tissue and more proteins that cause inflammation. We want to see if we can find these macrophages in the lungs of smokers before they get COPD. Recently, a 5 and a half year study showed that some smokers that can breathe normally have increased inflammation in their lungs. This can be seen using a scan called a CT scan. On the CT scan, these areas look like spots. When these smokers had another scan 5 and half years later, in some cases these spots had become holes in their lung. This is called emphysema and is one of the characteristics of COPD. We want to know whether the macrophages in these smokers cause this damage. If this is the case, we have two separate findings from this study. Firstly, we could look at macrophages and predict which smokers will develop COPD and secondly, try and develop new treatments to stop the macrophages from producing all proteins that cause inflammation.