Published: February 18, 2011 r2011 American Chemical Society 2428 dx.doi.org/10.1021/es1029415 | Environ. Sci. Technol. 2011, 45, 2428–2434 ARTICLE pubs.acs.org/est Evaluation of Mass and Surface Area Concentration of Particle Emissions and Development of Emissions Indices for Cookstoves in Rural India Manoranjan Sahu, †,‡ John Peipert, ‡,§,^ Vidhi Singhal, † Gautam N. Yadama, § and Pratim Biswas* ,† † Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental and Chemical Engineering, Campus Box 1180 Washington University in St. Louis, St. Louis, Missouri 63130, United Staytes § George Warren Brown School of Social Work, Campus Box 1196, Washington University in St. Louis, St. Louis, Missouri 63130, United States ^ Foundation of Ecological Security, Gujarat 38801, India b S Supporting Information ABSTRACT: Mass-based dose parameters (for example, PM 2.5 ) are most often used to characterize cookstove particulate matter emissions. Particle surface area deposition in the tracheobronchial (TB) and alveolar (A) regions of the human lung is also an important metric with respect to health effects, though very little research has investigated this dose parameter for cookstove emissions. Field sampling of cookstove emissions was performed in two regions of rural India, wherein PM 2.5 , particulate surface area concentration in both TB and A regions, and carbon monoxide (CO) were measured in 120 households and two roadside restaurants. Novel indices were developed and used to compare the emissions and efficiency of several types of household and commercial cookstoves, as well as to compare mass-based (PM 2.5 ) and surface area-based measurements of particle concentration. The correlation between PM 2.5 and surface area concentration was low to moderate: Pearson’s correlation coefficient (R) for PM 2.5 vs surface area concentration in TB region is 0.38 and for PM 2.5 vs surface area concentration in A region is 0.47, indicating that PM 2.5 is not a sufficient proxy for particle surface area concentration. The indices will also help communicate results of cookstove studies to decision makers more easily. ’ INTRODUCTION Over 2 billion people use biomass to cook, boil water, for heating, and other household needs, 1,2 and this number is expected to increase over the next decades. 3 This enormous scale of household biomass energy use demands attention from the public health and development communities given the known adverse impacts of the emissions from biomass cookstoves. 4-15 For decades, governments and NGOs have attempted to disseminate improved household stoves in devel- oping nations in order to facilitate more efficient and less harmful household cooking practices. 6 In this effort, alterations have been made to traditional biomass cookstoves commonly used in rural areas, and new, nonbiomass using stoves have also been offered. In the case of India, it is recognized that the disseminated improved stoves have not met their efficiency or emissions objectives, 7 and a very low fraction has been adopted for use. 8 A recent evaluation by the Ministry of New and Renewable Energy (MNRE), Government of India has resulted in the launch of a new national biomass cookstove initiative. 9 Extant research on cookstoves has analyzed several emissions types to investigate their health effects. Mass-based dose param- eters, especially PM 2.5 , are used most often to characterize cook- stove particle emissions. 10,11 Small particles usually have low mass compared to large particles but have large surface areas and, therefore, their concentrations are not accurately reflected in the mass concentration of the particles. Studies of particle emissions from noncookstove sources indicate that the surface area (SA) of smaller particles deposited in the lungs is an important dose parameter in determining health effects. 12-14 Park et al. 15 evaluated the exposure metrics by classifying them into ranks based on the different aerosol concentrations measured during cooking in kerosene or liquefied petroleum gas in residences in India. The analysis indicated that exposure ranking by mass and surface area was similar but was different when number concen- trations were used, thus illustrating the importance of selecting the exposure metric most relevant in evaluating adverse health impacts. 15 Ultrafine particles with diameters between 10 and 400 nm, where the deposition curves (International Commission on Radiological Protection (ICRP) model) exhibit their maxima, are of particular interest in studying health effects. 16 To the best of our knowledge, surface area has not been studied as a dose metric for biomass cookstove particle emissions in the past due to the unavailability of appropriate instruments. Recent develop- ments in design of an instrument to measure the surface area concentration of particles deposited in regions of the lung allow more health relevant measurements to be taken. 17 Field measurements of cookstove efficiency and emissions often produce a large set of disparately parametrized data. Indices can standardize these disparate factors or quantities for easier Received: August 26, 2010 Accepted: January 20, 2011 Revised: December 14, 2010