Background: Biomass burning and inefficient cookstoves contribute significantly to indoor air pollution (IAP) and pose outstanding public health issues (Sidhu M.K. et al. Sci. Total Environ 2017;586:419?429). There are still major knowledge gaps in associating IAP exposure with health impacts.

Objectives: A randomized control study was conducted to assess the impact of replacing traditional cooking by improved cookstoves (Save80) on IAP and lung function.

Methods: 907 study participants in two rural communities in Rwanda cooked with traditional (n= 557) or Save80 (n=350) for 32 months. Health data were collected using a questionnaire. Spirometry was performed, including measurements of FVC, FEV1, FEV1/FVC ratio and PEF. The composition of IAP, e.g., black carbon (BC), particle number, and mass concentration, was measured in 45 households before and after the shift to Save80 stoves.

Results: Transitioning to Save80 reduced the cooking time and IAP exposure by 30% and 50%, respectively. In houses with indoor kitchens, BC exposure ranged from 40 to 300 ?g m^-3 h^-1 for traditional methods, and reduced to a range of 16 to 230 ?g m^-3 h^-1 when using Save80.The Save80 group showed significant reduction of coughing and mucus production (p<0,01). Acceptable spirometry collected from 848 (520 vs. 328) participants revealed an increase of mean FVC in the Save80 group (2,83L vs. 2,73L, p<0,05) and mean FVC/Pred FVC (89% vs. 86%, p<0,05).

Conclusions: Results indicate that improved cookstoves reduce exposure to IAP and impact lung function in the study site. The chemical composition of IAP will be analyzed to estimate years of life lost. Further studies, especially to investigate long-term outcomes, are needed.