windows) as potentially-important determinants of IAP (Brauer and Saxena, 2002, Moschandreas et al, 2002, Freeman and Sanez de Tajeda, 2002; ESMAP/World Bank, 2002; Heltberg, et al., 2003). In theory, many innovations in construction, space configuration and cooking practices could have significant effects on IAP. However, all systematic research on IAP seems to have focused on the use of clean fuels and improved stoves. We are not aware of any controlled, scientifically-monitored research on the relationships between structural arrangements and IAP in developing countries.

To promote better understanding of these relationships, we have conducted a controlled experiment in Bangladesh to test whether changes in construction materials, space configurations and cooking locations can have significant effects on IAP. This paper summarizes our results. The remainder of the paper is organized as follows. Section 2 discusses our controlled experiments, and describes how indoor air and the ambient environment have been monitored for this exercise. In Sections 3 and 4 we summarize our experimental results. Section 5 provides a summary and discussion of policy implications.

# **2. Controlled Experiments in Bangladesh**

Previous World Bank research in Bangladesh, using the latest air monitoring technology and a national household survey, has found that IAP is dangerously high for many poor families. Concentrations of 300 ug/m<sup>3</sup> or greater for respirable airborne particulates (PM10) are common in Bangladeshi households, implying widespread exposure to a serious health hazard (Dasgupta et al., 2006)<sup>2</sup> . The findings also suggest wide variation in indoor air quality based on fuels, cooking locations, construction materials and ventilation practices.

The potential importance of these factors prompted our follow-on program of direct experimentation, to overcome uncertainties about causation that are inevitably associated with cross-sectional survey analyses. The experiments focus on structural arrangements that are already common among poor households in Bangladesh, since the literature on interventions to promote clean fuels and improved stoves is replete with disappointments stemming from reluctance of poor families to adopt innovations that are unfamiliar, unsupported by existing services, and potentially costly to maintain.

The controlled experiments were conducted in Burumdi village of Narayanganj district. Village Burumdi is located approximately 27 km away from the center of Dhaka, the capital of Bangladesh in South-East direction. The distance of the village from the nearest secondary road is 3 km. At the time of the experiments, there were approximately 290 houses in the village with 1,600 inhabitants in total<sup>3</sup> .

Architects familiar with climatic conditions and cultural constraints faced by Bangladeshi households studied building materials, housing configurations and constructiontechniques in different regions of the country, and developed an appropriate set of structural options. Figure 1: Architectural Design: As-Built Drawings

> 2 By way of comparison, Galassi, Ostro, et al. (2000) find substantial health benefits for PM10 reduction in eight Italian cities whose annual concentrations are far lower: 45-55 ug/m<sup>3</sup> .

> 3 Most of the villagers are either self-employed in non-agricultural sectors (e.g., fisherman, rickshaw puller) or are service providers.

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