Domestic smoke exposure is associated with alveolar macrophage particulate load

Indoor air pollution is associated with impaired respiratory health. The pre-dominant indoor air pollutant to which two billion of the world's population is exposed is biomass fuel smoke. We tested the hypothesis that reported smoke exposure in men and women is associated with increased alveolar macrophage uptake of biomass smoke particulates. Healthy volunteers attending for research bronchoscopy in Malawi completed a questionnaire assessment of smoke exposure. Particulate matter visible in alveolar macrophages (AM) was quantified using digital image analysis. The geometric mean of the percentage area of the cytoplasm occupied by particulates in 50 cover-slip adherent AM was calculated and termed particulate load. In 57 subjects (40 men and 17 women) there was a significant difference between the particulate load in groups divided according to pre-dominant lighting form used at home (anovaP = 0.0009) and type of cooking fuel (P = 0.0078). Particulate load observed in macrophages is associated with the reported type of biomass fuel exposure. Macrophage function in relation to respiratory health should now be investigated in biomass smoke exposed subjects.