Limited data suggest that outdoor air pollution (such as ambient air pollution or traffic related air pollution) and indoor air pollution (such as second hand smoking and biomass fuel combustion exposure) are associated with the development of chronic obstructive pulmonary disease (COPD) but there is insufficient evidence to prove a causal relationship at this stage.

It also appears that outdoor air pollution is a significant environmental trigger for acute exacerbation of COPD, leading to increasing symptoms, emergency department visits, hospital admissions and even mortality. Improving ambient air pollution and decreasing indoor biomass combustion exposure by improving home ventilation are effective measures that may substantially improve the health of the general public.