 Cigarette smoking causes an increase in inflammation in the lungs. In about 20 of smokers this inflammation leads to damage in lungs including making holes in the lung tissue. This damage can not be repaired and these people find it very difficult to breathe. One of the problems with this disease called chronic obstructive pulmonary disease, or COPD for short, is that by the time patients visit their doctor with symptoms, the damage has already been done. At the moment, there is no way to predict which smokers will go on to develop COPD. The aim of this research is to look at smokers who breathe normally and use an imaging technique called a CT scan, to look at their lungs in more detail. Some of these people will have spots on their scan which may be caused by inflammation. We want to look at the cells at these spots to see if they make more proteins and enzymes that cause lung damage when compared to people that do not have these spots. We would then be able to predict which smokers are likely to develop COPD and treat them early before they have damaged their lungs. 