• Smoking: Tobacco smoking is one of the chief causes of COPD. Smoking causes 90% of cases of COPD by producing inflammation of airway walls, exacerbating mucus production and interfering with normal functioning of air sacs.
• Air Pollution: Cooking fires fueled by coal or biomass fuels and urban air pollution increase the risk of exacerbations of COPD. Air pollution due to industries from various sources like coal mining, gold mining, cotton textile industries, fumes from welding, etc. cause occupational hazards in people working in these industries.
• Genetics: A family history of smokers has been observed to be one of the causes of COPD. Also, an inherited protein deficiency called alpha-1 antitrypsin may increase the risk of COPD, but it is a rare condition.