استفاده از روش جهانی تجزیه و تحلیل هزینه فایده برای مداخله کاهش آلودگی هوا در محیط داخلی در نپال، کنیا و سودان: بینش ها و چالش ها

Indoor air pollution from burning solid fuels for cooking is a major environmental health problem in developing countries, predominantly affecting children and women. Traditional household energy practices also contribute to substantial time loss and drudgery among households. While effective interventions exist, levels of investment to date have been very low, in part due to lack of evidence on economic viability. Between 2004 and 2007, different combinations of interventions – improved stoves, smoke hoods and a switch to liquefied petroleum gas – were implemented in poor communities in Nepal, Sudan and Kenya. The impacts were extensively evaluated and provided the basis for a household-level cost-benefit analysis, which essentially followed the methodology proposed by the World Health Organization. The results suggest that interventions are justified on economic grounds with estimated internal rates of return of 19%, 429% and 62% in Nepal, Kenya and Sudan, respectively. Time savings constituted by far the most important benefit followed by fuel cost savings; direct health improvements were a small component of the overall benefit. This paper describes the methodology applied, discusses the findings and highlights the methodological challenges that arise when a global approach is applied to a local programme.

More than three billion people worldwide depend on solid fuels, including biomass (i.e., wood, dung and agriculture residues) and coal, to meet their basic energy needs such as cooking, boiling water and heating (WHO, 2006). These solid biomass fuels lie at the bottom of the ‘energy ladder’ (WHO, 2006), and their inefficient combustion releases high concentrations of hundreds of health-damaging pollutants, such as particulate matter (PM) and carbon monoxide (CO). There is abundant evidence supporting the relationship between this indoor air pollution (IAP) and a broad range of health problems, in particular childhood acute lower respiratory infections (ALRI), chronic obstructive pulmonary disease (COPD) and lung cancer (where coal is used) (Smith et al., 2004). Moreover, studies have linked IAP exposure to a variety of other health outcomes, such as low birth weight and stillbirth (Pope et al., 2010), tuberculosis (Slama et al., 2010), asthma, cataracts (Bruce et al., 2000) and high blood pressure (McCracken et al., 2007b). Based on a comparative risk assessment undertaken by the World Health Organization (WHO), IAP is responsible for 1.6 million global deaths and 2.7% of the global burden of disease annually (WHO, 2006). A majority of the population living in the poorest countries of sub-Saharan Africa and South Asia continues to rely on solid fuels, and these countries also shoulder the largest share of the health burden. A number of technologies are available to solve the IAP problem. Switching from traditional to modern fuels, such as liquefied petroleum gas (LPG), biogas and ethanol, brings about the largest reductions in IAP. In many poor rural communities, however, access to these alternatives is limited by availability and affordability, and biomass remains the most practical fuel. Here, improved stoves – provided they are adequately designed, installed and maintained – can reduce IAP considerably. Stove location, housing construction and better ventilation are also partial remedies. All of these interventions have the potential to deliver a wide range of other benefits for poverty reduction and environmental sustainability. Despite the critical role household energy use plays for socio-economic development and the magnitude of the health effects, in particular among women and children, the problem has been largely ignored. The reasons are likely to be manifold, including low awareness about the health impacts of IAP among the affected populations and limited availability of locally appropriate and affordable cleaner cooking technologies. One reason for the lack of international recognition is the shortage of evidence on the effectiveness and cost-effectiveness of different solutions and on reliable mechanisms for their delivery. Showing that improved household energy interventions can be economically efficient should contribute to stimulating investment nationally and internationally, and to widespread adoption locally. The present study, carried out in Kenya, Sudan and Nepal, sought to understand how poor local communities could overcome the barriers that prevent them from accessing interventions to reduce IAP. A key output was to analyse the economic viability of various IAP-alleviating technologies using cost benefit analysis (CBA). We adapted the CBA guidelines developed by the WHO to a household perspective in these local settings. This report also describes the challenges that arise when global guidelines are applied and modified in the context of a specific local project, reviews methodological strengths and limitations, and compares findings with those of other CBA studies.

We carried out a household-perspective CBA for single- and mixed IAP-alleviating interventions in three distinct settings in Kenya, Sudan and Nepal. For all three, benefits exceed costs over a ten-year intervention period, suggesting that several household energy interventions not only produce health benefits but also make good economic sense. Benefit-cost ratios and internal rates of return vary markedly between settings. Similarly, the distribution of benefits shows considerable variation, mainly according to whether fuel is purchased or collected, and as a result of the amount of cooking time saved. One notable and consistent observation is the relatively small contribution from direct health benefits accruing due to reductions in IAP exposure. Arguably, several of our assumptions are subject to considerable uncertainty. While we did not conduct formal one-way or probabilistic sensitivity analysis, given the distribution of benefits it is clear that overall cost-benefit results are much affected by valuation of time savings and choice of discount rate. Valuing time savings more conservatively (for example, at ½ GNI per capita or at the minimum wage rate rather than at GNI per capita) would reduce economic efficiency in all three countries; in Nepal, it may result in the costs of the intervention exceeding its benefits. Some household perspective cost-benefit analyses employ discount rates exceeding 10%. The very high internal rates of return for Kenya and Sudan suggest that such a change would not affect our conclusions about economic efficiency; in Nepal, on the other hand, a discount rate of 19% would result in a net present value of zero and even higher discount rates would yield a negative net present value. Several of the challenges we encountered when conducting a ‘real-life’ CBA will need to be tackled. In particular, planning for CBA by selecting appropriate target populations and collecting data in the context of an ongoing development programme, whose natural evolution must not be disrupted, is critical. Household-level CBA should include a broader range of benefits and drawbacks as perceived by householders, including general aspects of well-being and impacts on the local and, where applicable, global environment. The assessment and valuation of health benefits also warrants further attention, in particular in relation to health benefits included, true incidence and prevalence of different diseases and levels of healthcare provision. Finally, future CBAs undertaken as part of local programmes should more formally examine the impact of uncertainties in assumptions about key parameters on results, and explore alternative ways of valuing benefits including willingness-to-pay. In this study, CBA results were used as a means of providing feedback to participating households, the implementing agency and the funding agency. They show that it pays off, from a household perspective, to invest in improved household energy. Nevertheless, high upfront investment costs for smoke hoods, improved biomass stoves or cleaner-fuel stoves represent a barrier that prevents poor households from adopting—and IAP continues to be one of the main causes of ill-health in poor communities of developing countries. Therefore, using the economic efficiency argument in the pursuance of policy development and implementation at national, regional and international levels are all the more important. We hope that our study, along with many more such studies, will help to secure more widespread political and policy attention to the issue, to develop more flexible and locally appropriate commercial approaches and to open up new ways of funding for the promotion of IAP-alleviating interventions.