Smoking

We know that smoking damages the cilia lining the lungs. As a result, a smoker’s lungs are not as effective at sweeping dust and bacteria out of the lungs.

This animation demostrates how the cilia in the lungs of a non-smoker protect the lung.

These tiny hair-like structures lining the inside of the bronchial tubes are constantly engaged in this sweeping motion, moving dust, bacteria, and viruses up and out of the lungs. Compare this to the cilia action inside the lungs of a smoker.

Since the smoker’s lungs are not as effective at sweeping dust, viruses, and bacteria up and out of the lungs, the smoker is more susceptible to frequent lung infections.