Smoking slowly damages your lungs, often without clear symptoms at first. Every cigarette releases thousands of toxic chemicals that enter your airways and lungs. Over time, this damage becomes serious and sometimes Systematic review with meta analysis of the epidemiological evidence relating smoking to COPD, chronic bronchitis and emphysema BMC Pulmonary Medicine Springer Nature Link Medical Marijuana for the Treatment of COPD Cannabis & COPD The Troubling Truth About COPD and Vaping University of Maryland Medical System Health Hub Medicor Research Inc.