Household use of unprocessed solid fuels (wood, dung, crop residues/grasses, and coal) for cooking and heating exposes large proportions of people in developing countries to high levels of toxic air pollutants indoors. Indoor smoke contains some of the same pollutants found in tobacco smoke and in ambient air, which have been linked with serious health consequences. There is growing evidence that exposure to indoor smoke can cause serious respiratory and other adverse health effects, but the quantity and quality of scientific literature vary considerably by type of health outcome. There is compelling evidence linking indoor smoke to acute respiratory infections in children and chronic obstructive pulmonary disease (COPD) or chronic bronchitis in women. But, the evidence linking indoor smoke to asthma, tuberculosis, lung cancer, and adverse pregnancy outcomes is limited and sometimes conflicting; and evidence linking indoor smoke to cataract and blindness, otitis media, lung fibrosis, and cardiovascular disease is weak or nonexistent. Many of the studies use indirect measures of smoke exposure and reported measures of health outcomes, do not adequately account for confounding and interactions, and few address gender aspects of smoke exposure and its health effects. Differences in gender roles result in differential exposures to indoor smoke among males and females; and gender differences in nutritional status, treatment, and care result in differential effects of these exposures. Moreover, there are biological and genetic differences between males and females that mediate the effects of smoke exposure on health. There is need to improve both the quality and quantity of research in this area, using better study designs, direct measures of smoke exposure, and clinical measures of health outcomes. To reduce exposures to indoor smoke, there is need to promote widespread use of cleaner fuels, provide improved cookstoves, and inform people about potential health risks, especially to women and young children.

Household use of unprocessed solid fuels (wood, dung, crop residues/grasses, and coal) for cooking and heating exposes large proportions of people in developing countries to high levels of toxic air pollutants indoors. Indoor smoke contains some of the same pollutants found in tobacco smoke and in ambient air, which have been linked with serious health consequences. There is growing evidence that exposure to indoor smoke can cause serious respiratory and other adverse health effects, but the quantity and quality of scientific literature vary considerably by type of health outcome. There is compelling evidence linking indoor smoke to acute respiratory infections in children and chronic obstructive pulmonary disease (COPD) or chronic bronchitis in women. But, the evidence linking indoor smoke to asthma, tuberculosis, lung cancer, and adverse pregnancy outcomes is limited and sometimes conflicting; and evidence linking indoor smoke to cataract and blindness, otitis media, lung fibrosis, and cardiovascular disease is weak or nonexistent. Many of the studies use indirect measures of smoke exposure and reported measures of health outcomes, do not adequately account for confounding and interactions, and few address gender aspects of smoke exposure and its health effects. Differences in gender roles result in differential exposures to indoor smoke among males and females; and gender differences in nutritional status, treatment, and care result in differential effects of these exposures. Moreover, there are biological and genetic differences between males and females that mediate the effects of smoke exposure on health. There is need to improve both the quality and quantity of research in this area, using better study designs, direct measures of smoke exposure, and clinical measures of health outcomes. To reduce exposures to indoor smoke, there is need to promote widespread use of cleaner fuels, provide improved cookstoves, and inform people about potential health risks, especially to women and young children.