Severe Pulmonary Disease Associated with Electronic CigaretteProduct Use Interim Guidance MMWR Emphysema vs. Chronic Bronchitis: What's the Difference? Smoking poses severe dangers to lung health, including: 1. Lung Cancer Smoking is the leading cause of lung cancer, increasing the risk of developing this deadly disease. 2. Chronic Obstructive Pulmonary Disease ( Association of electronic cigarette use and risk of COPD: a systematic review and meta analysis npj Primary Care Respiratory Medicine