In COPD, the risk attributable to smoking is very variable according to published studies. A significant number shows that the risk of COPD in non-smokers is far from negligible. The links between COPD and pollution of the interior environment vary between developed and developing countries.
State of the art

In developing countries, numerous studies have shown a link between COPD and exposure to substances derived from the combustion of biomass fuels, particularly in women where the exposure is the greatest. Nevertheless, a cause and effect relationship has not always been demonstrated. In developed countries, there is no evidence of a role of exposure to domestic interior pollution in the genesis of COPD and interior pollutants such as NO2 and particulates seem only to aggravate already existing COPD.
Conclusion : Further studies are necessary to evaluate their role in COPD and explore the underlying mechanisms. Irritative phenomena could be involved.