Biomass burning in Africa: Role in atmospheric change and opportunities for emission mitigation

A review of available literature published on biomass burning and trace gas emissions in Africa reveals household biofuel use, land use and land-use change to be the most important trace gas emission sources in Africa, contributing about 4% to the overall global C~ budget. This may not be significant in so far as altering global climate through temperature rise is concerned. However, through the contribution of about 35% of the global photochemical ozone formation, biomass burning in Africa significantly influences important atmospheric processes. Although the total greenhouse gas emissions from Africa are very low compared to those of other continents, countries on the continent could still contribute to global greenhouse gas mitigation efforts through ways that could simultaneously deliver urgent development needs

Biofuel availability and domestic use patterns in Kenya

The annual domestic consumption levels and patterns of various common biofuels in Kenya were surveyed. The main fuelwood sources were farmland trees, indigenous forests, woodlands and timber off-cuts from plantations. In 1997, about 15.4 million tonnes of firewood (air-dried) were consumed and an equivalent of 17.1 million tonnes round wood wet weight (w/w) was converted to charcoal. In the same year, 1.4 million tonnes of a variety of crop residues were also consumed as domestic fuel. Biofuel availability was the major factor influencing the reported annual spatial species use and consumption patterns. Competing demand for the commonly-used tree species (mainly eucalyptus trees) for commercial and other purposes accounts, to a large extent, for the reported dwindling amounts. Communities in various regions have responded by gradually shifting to other available types including those in gazetted forests. Such a response strategy has implications on the long-term spatial and temporal biofuel use patterns

Biofuel consumption rates and patterns in Kenya

A questionnaire survey was conducted in rural and urban Kenya to establish biofuel consumption rates and patterns. The survey targeted households, commercial catering enterprises and public institutions such as schools and colleges. Firewood was the main biofuel used, mostly by rural households, who consumed the commodity at average consumption rates in the range 0.8–2.7 kg cap−1 day−1. Charcoal was mostly consumed by the urban households at weighted average rates in the range 0.18–0.69 kg cap−1 day−1. The consumption rates and patterns for these fuels by restaurants and academic institutions, and those for crop residues are also reported. The rates largely depended on the fuel availability but differed significantly among the three consumer groups and between rural and urban households. Other factors which may have influenced consumption rates are discussed. Although good fuelwood sufficiency was reported in the country in 1997, there were increasing difficulties in accessing these resources by most households, a situation having both short- and long-term implications for biofuel consumption rates and patterns

Detection of lightning-produced NO in the midlatitude upper troposphere during STREAM 1998

Simultaneous in situ measurements of NO, NOy, HNO3, CO, CO2, O3, and aerosols were performed in the midlatitude upper troposphere (UT) and lower stratosphere during the Stratosphere-Trophosphere Experiment by Aircraft Measurements (STREAM) 1998 summer campaign. The campaign focused on the region around Timmins in the Canadian province of Ontario (79.3°W, 48.2°N), close to the polar jet stream that rapidly transports trace species across the Atlantic Ocean. This paper focuses on the origin of total reactive nitrogen (NOy) in the UT, as our measurements show strong variations, which reflect large local sources. In situ production by lightning, stratospheric downdraft, aircraft emissions, and upward transport of polluted boundary layer air are discussed in two case studies as potential contributors. We use correlations among NO, NOy and CO to distinguish between transport form the boundary layer and in situ formations. Lightning production of NOx is found to be a strong contributor to the budget of NOy during high NOy episodes