Health and Climate Change 1 Public health benefits of strategies to reduce greenhouse-gas emissions: household energ

Energy used in dwellings is an important target for actions to avert climate change. Properly designed and implemented, such actions could have major co-benefits for public health. To investigate, we examined the effect of hypothetical strategies to improve energy efficiency in UK housing stock and to introduce 150 million low-emission household cookstoves in India. Methods similar to those of WHO’s Comparative Risk Assessment exercise were applied to assess the effect on health that changes in the indoor environment could have. For UK housing, the magnitude and even direction of the changes in health depended on details of the intervention, but interventions were generally beneficial for health. For a strategy of combined fabric, ventilation, fuel switching, and behavioural changes, we estimated 850 fewer disability-adjusted life-years (DALYs), and a saving of 0·6 megatonnes of carbon dioxide (CO2), per million population in 1 year (on the basis of calculations comparing the health of the 2010 population with and without the specified outcome measures). The cookstove programme in India showed substantial benefits for acute lower respiratory infection in children, chronic obstructive pulmonary disease, and ischaemic heart disease. Calculated on a similar basis to the UK case study, the avoided burden of these outcomes was estimated to be 12 500 fewer DALYs and a saving of 0·1–0·2 megatonnes CO2-equivalent per million population in 1 year, mostly in short-lived greenhouse pollutants. Household energy interventions have potential for important co-benefits in pursuit of health and climate goals. Introduction Climate change presents a formidable challenge to societies throughout the world.1–3 Targets to limit the global temperature rise to around 2°C and the risk of dangerous climate change to a low level present a very challenging abatement path, needing a worldwide peak in greenhouse-gas emissions within only a few years and a steep fall that would halve emissions by around 2050.4 Even this target might be insufficiently ambitious. We employ the widely used term greenhouse gases, although since some anthropogenic climate-active atmospheric species are aerosols, greenhouse pollutants is a more accurate term. Most important of the climate-active aerosols produced by human activities are black carbon, sulphate, and organic carbon particles, which have important although not identical health effects, but quite different climate implications.5 Published Online November 25, 2009 DOI:10.1016/S0140- 6736(09)61713-X This is the first in a Series of six papers about health and climate change London School of Hygiene and Tropical Medicine, London, UK (P Wilkinson FRCP, Prof B G Armstrong PhD, Prof A Haines FMedSci, C Tonne ScD, Z Chalabi PhD); School of Public Health, University of California, Berkeley, CA, USA (Prof K R Smith PhD, H Adair BS); Bartlett School of Graduate Studies (Prof M Davies PhD, I Hamilton MSc, I Ridley PhD), and Energy Institute (M Barrett PhD, Prof T Oreszczyn PhD), University College London, London, UK; and Division of Public Health, University of Liverpool, Liverpool, UK (N Bruce PhD) Correspondence to: Dr Paul Wilkinson, PEHRU, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK Key messages • Many important health and climate outcomes are related to the products of incomplete combustion that are emitted from traditional solid fuel use in developing countries, even when little carbon dioxide (CO2) is produced overall. • Sustained national programmes to promote modern low-emissions stove technology for burning of local biomass fuels in poor countries provide a highly cost-beneficial means to potentially avert millions of premature deaths and hundreds of millions of tonnes of CO2-equivalent greenhouse pollutants. Such programmes could help countries to achieve Millennium Development Goals and climate targets, and offer one of the strongest climate–health links with respect to co-benefits. • Improvements in the efficiency of UK household energy use could, if implemented correctly, have appreciable benefits for population health, mainly arising from improved indoor air quality and control of winter indoor temperatures. (Continues in next column) (Continued from previous column) • For UK housing interventions, the magnitude and even direction of effects on health depend on how energy efficiency measures are implemented and maintained. Potential for adverse health outcomes arises from increases in indoor concentrations of pollutants, including radon and environmental tobacco smoke, in dwellings with energy efficiency measures that reduce air exchange; and increased ingress of outdoor particle pollutants with higher air exchange rates in dwellings fitted with mechanical ventilation systems unless there is effective filtering of air. • Household energy interventions in low-income settings have greater potential to improve public health than do those in high-income countries, but household energy interventions in high-income settings have potential for greenhouse-gas reduction per dwelling and are vital for achievement of climate abatement targets worldwide. Series 10 Urgent and profound changes in power generation and energy use in all sectors are therefore necessary, especially in high-income countries, where a halving of emissions is needed by 2030.4,6 Action to reduce energy use by households and in buildings is especially important because of the scale of their contribution to greenhouse-gas emissions and the opportunities for emissions reduction. Currently, energy use in UK residential buildings is estimated to account for around 140 megatonnes of carbon dioxide (CO2) emissions,4,7 or around 26% of the country’s total (table 1). Substantial reductions in these emissions are achievable with present technology and through energy efficiency, behavioural change, and low-carbon power generation.4 In low-income countries, where per head emissions are low, global principles of equitable burden sharing imply that less contraction in greenhouse-gas emissions is necessary compared with high-income countries, and even, in some cases, an increase to a sustainable per head worldwide average. But even in such settings, efficiency and cleanliness of household energy use can be improved, with both greenhouse-pollutant reductions and direct health benefits from reduced indoor and outdoor air pollution. Improvement of combustion efficiency of solid household fuels (biomass and coal) used by poor populations of developing countries is one of the greatest opportunities for health co-benefits worldwide and was amon