Emphysema is an example of a chronic change. Here is a list of the changes that happen in your lungs and airways when you smoke: 1  The cells that produce mucus in your lungs and airways grow in size and number. 2  As a result, the amount of mucus increases.3  The mucus is also thicker.mphysema is an example of a chronic change. Here is a list of the changes that happen in your lungs and airways when you smoke: 1  The cells that produce mucus in your lungs and airways grow in size and number. 2  As a result, the amount of mucus increases.