ERS/ATS workshop report on respiratory health effects of household air pollution.

Exposure to household air pollution (HAP) from solid fuel combustion affects almost half of the world population. Adverse respiratory outcomes such as respiratory infections, impaired lung growth and chronic obstructive pulmonary disease have been linked to HAP exposure. Solid fuel smoke is a heterogeneous mixture of various gases and particulates. Cell culture and animal studies with controlled exposure conditions and genetic homogeneity provide important insights into HAP mechanisms. Impaired bacterial phagocytosis in exposed human alveolar macrophages possibly mediates several HAP-related health effects. Lung pathological findings in HAP-exposed individuals demonstrate greater small airways fibrosis and less emphysema compared with cigarette smokers. Field studies using questionnaires, air pollution monitoring and/or biomarkers are needed to better establish human risks. Some, but not all, studies suggest that improving cookstove efficiency or venting emissions may be associated with reduced respiratory symptoms, lung function decline in women and severe pneumonia in children. Current studies focus on fuel switching, stove technology replacements or upgrades and air filter devices. Several governments have initiated major programmes to accelerate the upgrade from solid fuels to clean fuels, particularly liquid petroleum gas, which provides research opportunities for the respiratory health community.

Biomass smoke exposure and chronic lung disease.

PURPOSE OF REVIEW: Approximately 3 billion people worldwide rely on coal and biomass fuel for cooking and heating. Biomass smoke exposure is associated with several chronic lung diseases, including chronic obstructive pulmonary disease (COPD), asthma-COPD overlap syndrome, usual interstitial pneumonitis, hut lung, and bronchial anthracofibrosis. Household air pollution primarily from biomass smoke is the biggest risk factor for COPD worldwide. Despite the significant burden of biomass smoke-related respiratory disease, the exposure is still underappreciated worldwide, especially in high-income countries. RECENT FINDINGS: Recent literature highlights the immunoinflammatory differences between biomass smoke-related COPD and tobacco smoke-related COPD that may lead to better understanding of the differences in the clinical phenotypes between the two entities, suggests an association with the recently recognized asthma-COPD overlap syndrome, and elucidates the burden of disease in high-income countries. SUMMARY: The current review focuses on the association between biomass smoke and common chronic respiratory diseases, discuss differences between biomass smoke-related COPD and tobacco smoke-related COPD, highlights chronic respiratory diseases that are specific for biomass smoke exposure such as hut lung and bronchial anthracofibrosis, and discusses the known impact of beneficial interventions.

Chronic obstructive pulmonary disease secondary to household air pollution.

Approximately 3 billion people around the world cook and heat their homes using solid fuels in open fires and rudimentary stoves, resulting in household air pollution. Household air pollution secondary to indoor combustion of solid fuel is associated with multiple chronic obstructive pulmonary disease (COPD) outcomes. The exposure is associated with both chronic bronchitis and emphysema phenotypes of COPD as well as a distinct form of obstructive airway disease called bronchial anthracofibrosis. COPD from household air pollution differs from COPD from tobacco smoke with respect to its disproportionately greater bronchial involvement, lesser emphysematous change, greater impact on quality of life, and possibly greater oxygen desaturation and pulmonary hypertensive changes. Interventions that decrease exposure to biomass smoke may decrease the risk for incident COPD and attenuate the longitudinal decline in lung function, but more data on exposure-response relationships from well-designed longitudinal studies are needed.