African anthropogenic combustion emission inventory: specificities and uncertainties

Abstract:

Fossil fuel and biofuel emissions of gases and particles in Africa are expected to significantly increase in the near future, particularly due to the growth of African cities. In addition, African large savannah fires occur each year during the dry season, mainly for socio-economical purposes.

In this study, we will present the most recent developments of African anthropogenic combustion emission inventories, stressing African specificities.

(1)A regional fossil fuel and biofuel inventory for gases and particulates will be presented for Africa at a resolution of 0.25° x 0.25° from 1990 to 2012. For this purpose, the original database of Liousse et al. (2014) has been used after modification for emission factors and for updated regional fuel consumption including new emitter categories (waste burning, flaring) and new activity sectors (i.e. disaggregation of transport into sub-sectors including two wheel ). In terms of emission factors, new measured values will be presented and compared to litterature with a focus on aerosols. They result from measurement campaigns organized in the frame of DACCIWA European program for each kind of African specific anthropogenic sources in 2015, in Abidjan (Ivory Coast), Cotonou (Benin) and in Laboratoire d’Aérologie combustion chamber. Finally, a more detailed spatial distribution of emissions will be proposed at a country level to better take into account road distributions and population densities.

(2) Large uncertainties still remain in biomass burning emission inventories estimates, especially over Africa between different datasets such as GFED and AMMABB. Sensitivity tests will be presented to investigate uncertainties in the emission inventories, applying methodologies used for AMMABB and GFED inventories respectively.

Then, the relative importance of each sources (fossil fuel, biofuel and biomass burning inventories) on the budgets of carbon monoxide, nitrogen oxides, sulfur dioxide, black and organic carbon, and volatile organic compounds emission will be discussed for the years 1990-2012 at the region (West and Central Africa) and country (Ivory Coast and Benin) level and compared to existing inventories. Finally, a first tentative estimation of uncertainties will be conducted allowing to vary fuel consumption and emission factors for gases and particles.