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Background: 2.8 billion people cook with solid fuels, resulting in almost 3 million premature deaths from household air pollution (HAP). To date, no systematic assessment of impacts on HAP of 'improved' stove and clean fuel interventions has been conducted., Objective: This systematic review synthesizes evidence for changes in kitchen and personal PM 2.5 and carbon monoxide (CO) following introduction of 'improved' solid fuel stoves and cleaner fuels in low- and middle-income countries (LMIC)., Methods: Searches of published and unpublished literature were conducted through databases and specialist websites. Eligible studies reported mean (24 or 48h) small particulate matter (majority PM 2.5 ) and/or CO. Eligible interventions were solid fuel stoves (with/without chimneys, advanced combustion), clean fuels (liquefied petroleum gas, biogas, ethanol, electricity, solar) and mixed. Data extraction and quality appraisal were undertaken using standardized forms, and publication bias assessed. Baseline and post-intervention values and percentage changes were tabulated and weighted averages calculated. Meta-analyses of absolute changes in PM and CO were conducted., Results: Most of the 42 included studies (112 estimates) addressed solid fuel stoves. Large reductions in pooled kitchen PM 2.5 (ranging from 41% (29-50%) for advanced combustion stoves to 83% (64-94%) for ethanol stoves), and CO (ranging from 39% (11-55%) for solid fuel stoves without chimneys to 82% (75-95%) for ethanol stoves. Reductions in personal exposure of 55% (19-87%) and 52% (-7-69%) for PM 2.5 and CO respectively, were observed for solid fuel stoves with chimneys. For the majority of interventions, post-intervention kitchen PM 2.5 levels remained well above WHO air quality guideline (AQG) limit values, although most met the AQG limit value for CO. Subgroup and sensitivity analyses did not substantially alter findings; publication bias was evident for chimney stove interventions but this was restricted to before-and-after studies., Conclusions: In everyday use in LMIC, neither 'improved' solid fuel stoves nor clean fuels (probably due to neighbourhood contamination) achieve PM 2.5 concentrations close to 24-hour AQG limit values. Household energy policy should prioritise community-wide use of clean fuels., (Copyright © 2017. Published by Elsevier Ltd.)

Background: Around 2.4 billion people use traditional biomass fuels for household cooking or heating. In 2006, the International Agency for Research on Cancer (IARC) concluded emissions from household coal combustion are a Group 1 carcinogen, while those from biomass were categorised as 2A due to epidemiologic limitations. This review updates the epidemiologic evidence and provides risk estimates for the 2010 Global Burden of Disease study., Methods: Searches were conducted of 10 databases to July 2012 for studies of clinically diagnosed or pathologically confirmed lung cancer associated with household biomass use for cooking and/or heating., Findings: Fourteen eligible studies of biomass cooking or heating were identified: 13 had independent estimates (12 cooking only), all were case-control designs and provided 8221 cases and 11 342 controls. The ORs for lung cancer risk with biomass for cooking and/or heating were OR 1.17 (95% CI 1.01 to 1.37) overall, and 1.15 (95% CI 0.97 to 1.37) for cooking only. Publication bias was not detected, but more than half the studies did not explicitly describe a clean reference category. Sensitivity analyses restricted to studies with adequate adjustment and a clean reference category found ORs of 1.21 (95% CI 1.05 to 1.39) for men (two reports, compiling five studies) and 1.95 (95% CI 1.16 to 3.27) for women (five reports, compiling eight studies). Exposure-response evidence was seen for men, and higher risk for women in developing compared with developed countries, consistent with higher exposures in the former., Conclusions: There is now stronger evidence for biomass fuel use causing lung cancer, but future studies need better exposure assessment to strengthen exposure-response evidence., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

In the Comparative Risk Assessment (CRA) done as part of the Global Burden of Disease project (GBD-2010), the global and regional burdens of household air pollution (HAP) due to the use of solid cookfuels, were estimated along with 60+ other risk factors. This article describes how the HAP CRA was framed; how global HAP exposures were modeled; how diseases were judged to have sufficient evidence for inclusion; and how meta-analyses and exposure-response modeling were done to estimate relative risks. We explore relationships with the other air pollution risk factors: ambient air pollution, smoking, and secondhand smoke. We conclude with sensitivity analyses to illustrate some of the major uncertainties and recommendations for future work. We estimate that in 2010 HAP was responsible for 3.9 million premature deaths and ∼4.8% of lost healthy life years (DALYs), ranking it highest among environmental risk factors examined and one of the major risk factors of any type globally.