Abstract
Indoor air pollution (IAP) is dangerously high for many poor families in Bangladesh. Concentrations of 300 ug/m3 for respirable airborne particulates (PM10) or greater are common in Bangladeshi households, implying widespread exposure to a serious health hazard.
To promote a better understanding of IAP, in 2003, the World Bank’s research department has investigated the IAP in Bangladesh using the latest air monitoring technology and a national household survey (IAP Research, Phase I). The analysis of determinants of IAP verifies the IAP reducing potential of clean fuels (kerosene, natural gas, etc.), but the nationwide survey results revealed: Poor households in Bangladesh (like in other parts of Asia and Latin America) almost always use “dirty” biomass fuels, because in most rural areas, clean fuels are not available at all. Even where a clean fuel is available, poor households prefer and use “dirty” fuels because the relative price of the “clean” fuel is simply too high. Improved stoves for biomass combustion could help but, as other studies in Asia and Latin America have also discovered, the World Bank survey found almost no adoption of improved stoves despite widespread promotional efforts in Bangladesh. Households report non-adoption for a variety of reasons, including capital and maintenance costs, inconvenience, and incompatibility with food preparation traditions. Thus, neither clean fuels nor improved stoves offer strong prospects for reducing IAP in the rural area in near future.
Fortunately, the World Bank study has identified another option that looks much more promising. In Bangladesh, common variations in certain household characteristics -- construction materials, space configurations, cooking locations and use of doors and windows -- have produced large differences in IAP exposure. As a result, some poor households using “dirty” fuels enjoy indoor air quality normally associated with clean fuels, while others suffer from pollution levels ten times the international safe standard. Since many poor households already have some of the relevant characteristics, they are clearly acceptable and affordable in Bangladesh. The IAP-Phase I research, therefore, has tentatively concluded that a national “clean household” promotion program, combined with effective public education on the associated health benefits, could reduce IAP exposure to much safer levels for many poor families.
Although the general results are quite robust, the first-round research has only been able to consider a subset of feasible measures that might yield significant benefits in this context. Before proposing a national “clean household” program to policy makers, one needs to establish a broader and more rigorously-confirmed set of clean characteristics as well as to assess their cost effectiveness in different regions of Bangladesh. Current research in Bangladesh has conducted a program of direct, controlled experimentation and cost-effectiveness analysis that will provide the needed evidence. The experimentation of the research is confined to structural arrangements(building materials, cooking locations, window/ door configurations etc.) that are already common among poor households in Bangladesh.
The World Bank study has used two types of equipment: real-time monitors that record PM10 at 2-minute intervals, and air samplers that measure 24-hour average PM10 concentrations.
1. The real-time monitoring instrument is the Thermo Electric Personal DataRAM (pDR-1000). The pDR-1000 uses a light scattering photometer (nephelometer) to measure airborne particle concentrations. The operative principle is real-time measurement of light scattered by aerosols, integrated over as wide a range of angles as possible. At each location, the instrument operated continuously, without intervention, for a 24-hour period to record PM10 concentrations at 2-minute intervals.
2. The other instrument used in the study is the Airmetrics MiniVol Portable Air Sampler (Airmetrics, 2004), a more conventional device that samples ambient air for 24 hours. While the MiniVol is not a reference method sampler, it gives results that closely approximate data from U.S. Federal Reference Method samplers. The MiniVols were programmed to draw air at 5 liters/minute through PM10 particle size separators (impactors) and then through filters. The particles were caught on the filters, and the filters were weighed pre- and post exposure with a microbalance.
