Emphysema vs. Chronic Bronchitis: Key Differences (2026) 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 ( What Is COPD? An Overview of COPD MyHeart Emphysema vs. Chronic Bronchitis: What's the Difference? Elevated risk of developing COPD with e cigarette use: Study