| Charcoal is a processed-biomass fuel used for household cooking and space heating in many parts of the developing world, particularly the African continent, where cleaner fuels such as petroleum products or electricity are unavailable or unaffordable. In this dissertation I developed and tested methods for the quantification of the airborne emissions from several types of charcoal-making kilns commonly used throughout the developing world. Complete carbon balances and emission factors (amount of pollutant emitted per unit activity) for carbon dioxide, methane, carbon monoxide, hydrocarbons, and particulates were experimentally determined for several kiln types in Thailand, Kenya, and Brazil. The relationships between kiln type, operator know-how, kiln efficiency, and greenhouse gas emissions were examined. The charcoal-making emission factors determined herein were combined with existing data on charcoal and fuelwood stove emissions. Empirical relationships (exponential and linear fits) were derived for greenhouse gas emissions, indoor air pollutant emissions, and fuelwood use versus charcoal kiln and charcoal stove efficiencies, as well as versus fuelwood stove efficiency. These three impacts were combined to form the charcoal and fuelwood impact (CFI) index, which was then used to compare the impact of charcoal use to that of fuelwood use over a range of kiln and stove efficiencies. The CFI index showed that the environmental and human health impacts of charcoal and fuelwood are likely quite comparable, that neither is definitively cleaner than the other. What was clearly elucidated by the CFI index were the substantial benefits of achieving higher efficiencies, due to either kiln operator expertise, improved kilns, or improved stoves. The CFI index also demonstrated that even if maximum efficiencies are achieved, the environmental and human health effects of both the charcoal and fuelwood cycles are vastly greater than those from biogas or petroleum fuels such as liquefied petroleum gas (LPG) and kerosene. Hence, neither charcoal nor fuelwood should be considered a sustainable, nor preferable, household fuel choice. Rising awareness of and concern for the global environment and international health provide a mechanism for assisting poor households with the transition away from such dirty fuels. |
