A person can get lung disease through a number of different ways such as through smoking, pollutants in the air, breathing in smoke from a fire, breathing in fumes that are dangerous etc.
Lung disease can also occur through bacterial infections as well.
So it's possible to get lung disease even when you never smoked cigarettes in your life but of course you could still get lung disease from inhaling second hand smoke.
You can also get lung disease through being infected with the bacteria Mycobacterium tuberculosis which is a slowly progressive pneumonia.
Emphysema which is also a lung disease results from damage to the fragile connections between alveoli which is most commonly caused by smoking but you can still get it from breathing in smoke from other people or through the air from fires.