People don't just have to worry about outdoor air pollution; they need to take measures even to reduce air pollution indoors. In this study associations between indoor air pollutants and building ventilation or cooking are being observed.
The study found that the local outdoor levels of certain pollutants and ozone were the most important determinants of indoor levels of the same air pollutants.
"Ample burning of wood in small-scale room heaters and sauna stoves is likely to increase chronic personal exposures in the neighborhood to particulate matter that contains substantial amounts of soot and hazardous organic compounds like polycyclic organic hydrocarbons. This exposure does not take place only while staying outdoors but also indoors at home due to the effective passage of the small particles through the building shield," the authors wrote.