Comparison of Carbon Monoxide and Particulate Matter Emissions from Residential Burnings of Pelletized Biofuels and Traditional Solid Fuels

Widespread use of solid fuels affects indoor/outdoor air quality, human health, and climate change significantly. Replacing traditional solid fuels with affordable cleaner fuels is a challenge for most developing countries. In this study, carbon monoxide (CO) and particulate matter (PM) emissions and financial costs of a potential cleaner fuel-pelletized biofuels were compared to those of traditional solid fuels, including coal, crop residue, and wood, and a conventional modern fuel, liquid petroleum gas (LPG), in terms of fuel-mass-based emission factor (EF), delivered-energy-based emission factor (EFE), and delivered-energy-based cost (C-E). The combustions of pelletized fuels and LPG had not only relatively higher thermal efficiencies but also lower EFs, leading to much lower EFE of these cleaner fuels. The adoption of pelletized fuels burned in a modern pellet burner could reduce pollutant emissions significantly in comparison to traditional solid fuels. When both EFE and C-E are taken into consideration, it could be found that the nearly free ordinary biomass fuels and high-cost coals had much higher pollutant emissions, while LPG was the most expensive, although it would produce the lowest emission. Pelletized fuels appear to be a good alternative in rural households because of not only lower pollutant emissions but also relatively low cost. Future studies, including but not limited to emission measurements, potential reductions in air concentrations and health outcome, systematic cost-benefit analysis, and identification of key enablers and barriers affecting the large-scale uptake, are strongly recommended.