Physical characterization of particulate matter emitted from wood combustion in improved and traditional cookstoves

Experiments were conducted to investigate the particle characteristics emitted from 10 wood types combusted in a traditional and an improved cookstove. The performance of the cookstoves has been assessed on the basis of their thermal efficiency using water boiling test (WBT). An aerosol spectrometer (GRIMM 1.108) was used for particulate matter sampling which provides real time data of size resolved particle concentrations. Variation in particle size distribution during different combustion phases was also analyzed. Particle size distribution (PSD) with respect to number, surface area and volume was studied to find out most dominant PM size range along with PM emission factors (EFs). Improved, top feed, cookstove was found to perform better than the traditional cookstove, both in terms of thermal efficiency and emissions. Around 99% of the particles were found in the fine range of 0.3-1 mu m for both the cookstoves. Count median diameter (CMD) for improved cookstove was found to be 1.47 (with 3.76 as Geometric standard deviation (GSD)) as compared to 1.55 (with 3.73 as GSD) for the traditional cookstove, indicating a shift towards fine range particles. The total particle-number emission factor (TPNEF) and mass emission factor (MEF) for ten wood types were higher in traditional cookstove with an average value of 2.7 x 10(13) kg(-1) and 6.17 g kg(-1) respectively. In case of improved cookstove TPNEF and MEF were found to be 7.6 x 10(12) kg(-1) and 0.72 g kg(-1) respectively indicating significant decrease in PM emissions. The size range of particles was also validated with scanning electron microscopy (SEM) by calculating actual size of the primary particles emitted from the combustion of a particular wood type. The findings of this study highlight the effect of cookstove design on resultant particle emissions and their distribution in various size ranges. (C) 2013 International Energy Initiative. Published by Elsevier Inc. All rights reserved.