[Etiological and exacerbation factors for COPD. Air pollution].

Recently, it has been found that the number of patients with chronic obstructive pulmonary disease (COPD) who do not have a history of smoking is higher than expected, and a number of factors affect the development of COPD. Although adequate evidence for the relation of ambient air pollution, including the presence of particulate matter (PM2.5), with the development of COPD is lacking, higher mortality from respiratory and cardiovascular diseases has been reported among patients exposed to air pollution for a long time. In addition, several reports have pointed out the possibility that acute exacerbation of COPD can be caused by short-term exposure to air pollution. Tobacco smoke is the main cause of highly concentrated PM2.5 indoors, and second hand smoke is related with the development of COPD and the high mortality from COPD. In developing countries, biomass fuel combustion contributes to COPD, especially among housewives who do not smoke.