NITROGEN DIOXIDE AND HOUSEHOLD AIR POLLUTION FROM BIOMASS AND LIQUEFIED PETROLEUM GAS COOKSTOVES

Problem Statement: Household air pollution (HAP) from biomass cookstoves is a leading contributor to the global burden of disease. Current research and intervention efforts have focused on PM2.5 and CO as the pollutants from biomass emissions that are most relevant to public health. However, little is known about the emissions, exposures, and health effects of nitrogen dioxide (NO2) from biomass cookstoves or from cleaner-cooking alternatives. This dissertation aimed to 1) characterize NO2 concentrations in kitchens with biomass cookstoves, 2) examine the multi-pollutant exposure-response relationships between PM2.5, CO, and NO2 and lung function among women with biomass stoves, and 3) evaluate the longitudinal impact of a liquefied petroleum gas (LPG) stove intervention on NO2 concentrations. Methods: We conducted a randomized, controlled field trial of a biomass-to-LPG cookstove intervention among women with biomass cookstoves in Puno, Peru. In the first manuscript, we measured NO2 kitchen area concentrations and personal exposures in homes with biomass cookstoves at baseline. In the second manuscript, we measured lung function via spirometry, PM2.5, and CO, and we analyzed the multi-pollutant exposure-response associations between pollutants and lung function at baseline. In the third manuscript, we measured NO2 kitchen area concentrations and personal exposure in both arms of the intervention trial throughout the intervention period to assess the longitudinal impact of a biomass-to-LPG intervention on NO2 exposures. Results: In our first study, we observed high NO2 concentrations in homes with biomass cookstoves which far exceed WHO indoor hourly and annual guidelines. In our second study, we observed independent associations between lung function parameters and both NO2 and CO. In our third study, we found that a biomass-to-LPG intervention reduced NO2 exposures, but kitchen area NO2 concentrations in homes with LPG stoves remained above WHO guidelines. Conclusions: Biomass cookstoves in the Peruvian Andes produce NO2 emissions which far exceed WHO guidelines. These exposures may have negative effects on respiratory function, independent of PM2.5 and CO. While LPG stoves reduced NO2 exposure, indoor concentrations remained above WHO guidelines. Further research is warranted to inform the promotion of LPG stoves as a safe and effective public health intervention