iv scénario REF en 2030 avec des hausses de plus de 67% entre les années 2005 et 2030. Enfin, des... more iv scénario REF en 2030 avec des hausses de plus de 67% entre les années 2005 et 2030. Enfin, des tests de sensibilité ont été effectués sur l'année 2030, en considérant que les engins deux roues avaient tous des moteurs quatre temps au lieu des deux temps « actuels » en Afrique de l'Ouest et, en Afrique du Sud en appliquant les ratios de projections de la Pologne, typique de pays émergeants. Ces hypothèses de travail ont permis de réduire considérablement les émissions futures, surtout dans le scénario CCC. Enfin, nous avons simulé les concentrations ambiantes à partir des données de nos nouveaux inventaires 2005 en utilisant le modèle global TM5. Il ressort des résultats 2005 que ce modèle peut simuler de manière satisfaisante les concentrations en zones rurales, moins bien en zones urbaines. Ces différences peuvent s'expliquer par un maillage trop grossier du modèle (1° x 1°) et le site choisi (site trafic où les concentrations sont maximales). Du point de vue des épaisseurs optiques, le modèle fournit des ordres de grandeur satisfaisants avec cependant un positionnement encore imparfait des maxima en Afrique de l'Ouest et en Afrique Centrale. Pour l'albédo de simple diffusion, nos résultats sont encourageants, sachant que le carbone suie et le carbone organique sont seuls pris en compte dans notre modèle global TM5.
Abstract: Wildfires take a heavy toll on human health worldwide. Climate change may increase the ... more Abstract: Wildfires take a heavy toll on human health worldwide. Climate change may increase the risk of wildfire frequency. Therefore, in view of adapted preventive actions, there is an urgent need to further understand the health effects and public awareness of wildfires. We conducted a systematic review of non-accidental health impacts of wildfire and incorporated lessons learned from recent experiences. Based on the literature, various studies have established the relationship between one of the major components of wildfire, particulate matter (particles with diameter less than 10 µm (PM10) and less than 2.5 µm (PM2.5)) and cardiorespiratory symptoms in terms of Emergency Rooms visits and hospital
Municipal Solid Waste landfilling is the most common waste elimination in the developing countrie... more Municipal Solid Waste landfilling is the most common waste elimination in the developing countries in general and particularly in Côte d’Ivoire. However, gaseous emissions from waste landfilled constitute an environment and human health concern by contributing to greenhouse gas effects, odour problems, explosion and fire hazards as well as sources of air pollution. In this study, methane emissions rates from Akouédo (Abidjan) landfill have been estimated using three theoretical models such as Landfill Gas Emission Model (LandGEM, version 3.02), Intergovernmental Panel on Climate Change (IPCC) waste model and Solid Waste Emissions Estimation Tool (SWEET). Two types of parameters have been used to estimate methane emissions, default parameters and site-specific parameters. The results of simulations of the three models are compared as well as the results from their default and sitespecific parameters. Results show that LandGEM simulations using both default and site-specific parameter...
Recent simulations have shown a gap between observed and modeled aerosol optical depths above the... more Recent simulations have shown a gap between observed and modeled aerosol optical depths above the Guinean Gulf in West Africa, assuming the possible role of flaring emissions which are really important in this area and not accounted for in this work. It can be expected that these emissions also impact regional air quality and health. In this presentation, recent developments on flaring emission inventories for aerosols and gases obtained from DMSP satellite for the years 1990-2012 and validated over Nigeria will be presented and discussed in terms of temporal and spatial variability. By introducing such emission inventories in RegCM regional climatic model in addition to other anthropogenic sources (traffic, domestic fires, industries, charcoal making, biomass burning..) we will study the relative contributions of the different emissions sources on air quality, climate and health.
Road traffic emission inventories based on bottom-up methodology, are calculated for each road se... more Road traffic emission inventories based on bottom-up methodology, are calculated for each road segment from fuel consumption and traffic volume data obtained during field measurements in Yopougon. High emissions of black carbon (BC) from vehicles are observed at major road intersections, in areas surrounding industrial zones and on highways. Highest emission values from road traffic are observed for carbon monoxide (CO) (14.8 t/d) and nitrogen oxides (NOx) (7.9 t/d), usually considered as the major traffic pollution tracers. Furthermore, peak values of CO emissions due to personal cars (PCs) are mainly linked to the old age of the vehicle fleet with high emission factors. The highest emitting type of vehicle for BC on the highway is PC (70.2%), followed by inter-communal taxis (TAs) (13.1%), heavy vehicles (HVs) (9.8%), minibuses (GBs) (6.4%) and intra-communal taxis (WRs) (0.4%). While for organic carbon (OC) emissions on the main roads, PCs represent 46.7%, followed by 20.3% for W...
There are very few African regional inventories providing biofuel and fossil fuel emissions. With... more There are very few African regional inventories providing biofuel and fossil fuel emissions. Within the framework of the DACCIWA project, we have developed an African regional anthropogenic emission inventory including the main African polluting sources (wood and charcoal burning, charcoal making, trucks, cars, buses and two-wheeled vehicles, open waste burning, and flaring). To this end, a database on fuel consumption and emission factors specific to Africa was established using the most recent measurements. New spatial proxies (road network, power plant geographical coordinates) were used to convert national emissions into gridded inventories at a 0.1 • × 0.1 • spatial resolution. This inventory includes carbonaceous particles (black and organic carbon) and gaseous species (CO, NO x , SO 2 and NMVOCs) for the period 1990-2015 with a yearly temporal resolution. We show that all pollutant emissions are globally increasing in Africa during the period 1990-2015 with a growth rate of 95 %, 86 %, 113 %, 112 %, 97 % and 130 % for BC, OC, NO x , CO, SO 2 and NMVOCs, respectively. We also show that Western Africa is the highest emitting region of BC, OC, CO and NMVOCs, followed by Eastern Africa, largely due to domestic fire and traffic activities, while Southern Africa and Northern Africa are the highest emitting regions of SO 2 and NO x due to industrial and power plant sources. Emissions from this inventory are compared to other regional and global inventories, and the emissions uncertainties are quantified by a Monte Carlo simulation. Finally, this inventory highlights key pollutant emission sectors in which mitigation scenarios should focus on. The DACCIWA inventory (
A number of campaigns have been carried out to establish the emission factors of pollutants from ... more A number of campaigns have been carried out to establish the emission factors of pollutants from fuel combustion in West Africa, as part of work package 2 ("Air Pollution and Health") of the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) FP7 program. Emission sources considered here include wood (hevea and iroko) and charcoal burning, charcoal making, open trash burning, and vehicle emissions, including trucks, cars, buses and two-wheeled vehicles. Emission factors of total particulate matter (TPM), elemental carbon (EC), primary organic carbon (OC) and volatile organic compounds (VOCs) have been established. In addition, emission factor measurements were performed in combustion chambers in order to reproduce field burning conditions for a tropical hardwood (hevea), and obtain particulate emission factors by size (PM 0.25 , PM 1 , PM 2.5 and PM 10). Particle samples were collected on quartz fiber filters and analyzed using gravimetric method for TPM and thermal methods for EC and OC. The emission factors of 58 VOC species were determined using offline sampling on a sorbent tube. Emission factor results for two species of tropical hardwood burning of EC, OC and TPM are 0.98 ± 0.46 g kg −1 of fuel burned (g kg −1), 11.05 ± 4.55 and 41.12 ± 24.62 g kg −1 , respectively. For traffic sources, the highest emission factors among particulate species are found for the two-wheeled vehicles with two-stroke engines (2.74 g kg −1 fuel for EC, 65.11 g kg −1 fuel for OC and 496 g kg −1 fuel for TPM). The largest VOC emissions are observed for two-stroke two-wheeled vehicles, which are up to 3 times higher than emissions from light-duty and heavyduty vehicles. Isoprene and monoterpenes, which are usually associated with biogenic emissions, are present in almost all anthropogenic sources investigated during this work and could be as significant as aromatic emissions in wood burning (1 g kg −1 fuel). EC is primarily emitted in the ultrafine fraction, with 77 % of the total mass being emitted as particles smaller than 0.25 µm. The particles and VOC emission factors obtained in this study are generally higher than those in the literature whose values are discussed in this paper. This study underlines the important role of in situ measurements in deriving realistic and representative emission factors.
A regional fossil fuel and biofuel emission inventory for particulates has been developed for Afr... more A regional fossil fuel and biofuel emission inventory for particulates has been developed for Africa at a resolution of 0.25° x 0.25° for the year 2005. The original database of Junker and Liousse (2008) was used after modification for updated regional fuel consumption and emission factors. Consumption data were corrected after direct inquiries conducted in Africa, including a new emitter
h i g h l i g h t s Review of methods used to assess wildfire exposure and related health impact.... more h i g h l i g h t s Review of methods used to assess wildfire exposure and related health impact. Discussion of uncertainties of exposure assessment in the literature. Application of methods which allowed to have emissions at local area.
International Journal of Environmental Research and Public Health, 2014
Wildfires take a heavy toll on human health worldwide. Climate change may increase the risk of wi... more Wildfires take a heavy toll on human health worldwide. Climate change may increase the risk of wildfire frequency. Therefore, in view of adapted preventive actions, there is an urgent need to further understand the health effects and public awareness of wildfires. We conducted a systematic review of non-accidental health impacts of wildfire and incorporated lessons learned from recent experiences. Based on the literature, various studies have established the relationship between one of the major components of wildfire, particulate matter (particles with diameter less than 10 µm (PM 10) and less than 2.5 µm (PM 2.5)) and cardiorespiratory symptoms in terms of Emergency Rooms visits and hospital
Emissions of gases and particles from the combustion of fossil fuels and biofuels in Africa are e... more Emissions of gases and particles from the combustion of fossil fuels and biofuels in Africa are expected to increase significantly in the near future due to the rapid growth of African cities and megacities. There is currently no regional emissions inventory that provides estimates of anthropogenic combustion for the African continent. This work provides a quantification of the evolution of African combustion emissions from 2005 to 2030, using a bottom-up method. This inventory predicts very large increases in black carbon, organic carbon, CO, NO x , SO 2 and non-methane hydrocarbon emissions if no emission regulations are implemented. This paper discusses the effectiveness of scenarios involving certain fuels, specific to Africa in each activity sector and each region (western, eastern, northern and southern Africa), to reduce the emissions. The estimated trends in African emissions are consistent with emissions provided by global inventories, but they display a larger range of values. African combustion emissions contributed significantly to global emissions in 2005. This contribution will increase more significantly by 2030: organic carbon emissions will for example make up 50% of the global emissions in 2030. Furthermore, we show that the magnitude of African anthropogenic emissions could be similar to African biomass burning emissions around 2030.
Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of clima... more Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of climate at Lamto (6.13°N, 5.02°W) in Côte d’Ivoire. A combined pluviothermal index is used to identify climate regions of West Africa. The interdecadal change of the climate is analyzed along with a discussion on the West African Monsoon (WAM) circulation. The impact of vegetation is also analyzed. It is shown that Lamto has mainly a subhumid climate but, in some particular years, this area has a humid climate. Two decades (1962–1971 and 2002–2011) exhibit rainfall excess and the last three ones (1972–1981, 1982–1991, and 1992–2001) show a rainfall deficit that affected West Africa in the early 1970s. The meridional wind field from 1000 hPa to 700 hPa is used to study the WAM variability. The level of the WAM is the lowest (~860–890 hPa) during the active period of the northern wind coming from the Sahara desert (November–February). During 1962–1971 and 2007–2009, the depth of the monsoon at ...
Real time measurements of Black Carbon (BC) in PM 2.5 aerosols were performed during AMMA and POL... more Real time measurements of Black Carbon (BC) in PM 2.5 aerosols were performed during AMMA and POLCA programs, between 2005 and 2010 in Cotonou (Benin), Dakar (Senegal), Bamako (Mali), and Yaounde (Cameroon). Indeed, BC was chosen as a metric because of its interest as an urban pollutant. The instrumented sites are representative of the traffic source. At Dakar, BC concentrations are high from November to April (13,000 AE 3500 ng m À3) and lower from May to September (8000 AE 3200 ng m À3). In dry season (NovembereApril), high BC concentrations occurred as a result of northeasterly long-range transport of polluted air masses over West Africa, in addition to local emissions. However, during wet season (MayeSeptember) reduced traffic levels, school vacations and wet deposition processes contribute to lower BC concentration levels. Measured diurnal BC peak concentrations, at all sites, mainly occur during morning and evening rush-hour periods, indicating the paramount role of traffic. Highest values are observed between 5e9 a.m. and from 5 p.m. to 9 p.m. depending on the site, while lowest are occurred at night time and middle afternoon when activities of the population are reduced. BC source apportionment from absorption measurements also confirmed the relative importance of traffic (88%) versus biomass burning (12%). Also, BC measurements were functions of days of the week, with highest values occurring on Fridays and lowest ones on Sundays. Spatial variations associated to BC levels are very different from one site to another, revealing different types of sources with strong variations at the regional scale. It appears that mean BC concentrations in Dakar are lower by a factor of two, compared to those observed in Bamako, but remain higher than in some other West African sites (e.g. Cotonou, Yaounde). Overall, BC concentrations in our different sites are comparable to reported European and Asian megacity levels. Finally, using measured BC/PM 2.5 ratios, we have estimated PM 2.5 mass concentrations in Dakar from June 2008 to June 2009 to be 44.4 AE 14.3 mg m À3 , well above the WHO (2005) threshold of 10 mg m À3. This paper clearly highlights high pollution levels in West African large cities, with potential important impacts on the health of the regional population.
This pollution mainly derives from road traffic emissions with, in some capitals (e.g. Cotonou), ... more This pollution mainly derives from road traffic emissions with, in some capitals (e.g. Cotonou), the strong contribution of two-wheel vehicles. Two key questions arise: are presently available emission inventories (e.g. Junker, C., Liousse, C., 2008. A global emission inventory of carbonaceous aerosol from historic records of fossil fuel and biofuel consumption for the period 1860e1997.
African biomass burning emission inventories for gaseous and particulate species have been constr... more African biomass burning emission inventories for gaseous and particulate species have been constructed at a resolution of 1 km by 1km with daily coverage for the 2000-2007 period. These inventories are higher than the GFED2 inventories, which are currently widely in use. Evaluation specifically focusing on combustion aerosol has been carried out with the ORISAM-TM4 global chemistry transport model which includes a detailed aerosol module. This paper compares modeled results with measurements of surface BC concentrations and scattering coefficients from the AMMA Enhanced Observations period, aerosol optical depths and single scattering albedo from AERONET sunphotometers, LIDAR vertical distributions of extinction coefficients as well as satellite data. Aerosol seasonal and interannual evolutions over the 2004-2007 period observed at regional scale and more specifically at the Djougou (Benin) and Banizoumbou (Niger) AMMA/IDAF sites are well reproduced by our global model, indicating that our biomass burning emission inventory appears reasonable.
iv scénario REF en 2030 avec des hausses de plus de 67% entre les années 2005 et 2030. Enfin, des... more iv scénario REF en 2030 avec des hausses de plus de 67% entre les années 2005 et 2030. Enfin, des tests de sensibilité ont été effectués sur l'année 2030, en considérant que les engins deux roues avaient tous des moteurs quatre temps au lieu des deux temps « actuels » en Afrique de l'Ouest et, en Afrique du Sud en appliquant les ratios de projections de la Pologne, typique de pays émergeants. Ces hypothèses de travail ont permis de réduire considérablement les émissions futures, surtout dans le scénario CCC. Enfin, nous avons simulé les concentrations ambiantes à partir des données de nos nouveaux inventaires 2005 en utilisant le modèle global TM5. Il ressort des résultats 2005 que ce modèle peut simuler de manière satisfaisante les concentrations en zones rurales, moins bien en zones urbaines. Ces différences peuvent s'expliquer par un maillage trop grossier du modèle (1° x 1°) et le site choisi (site trafic où les concentrations sont maximales). Du point de vue des épaisseurs optiques, le modèle fournit des ordres de grandeur satisfaisants avec cependant un positionnement encore imparfait des maxima en Afrique de l'Ouest et en Afrique Centrale. Pour l'albédo de simple diffusion, nos résultats sont encourageants, sachant que le carbone suie et le carbone organique sont seuls pris en compte dans notre modèle global TM5.
Abstract: Wildfires take a heavy toll on human health worldwide. Climate change may increase the ... more Abstract: Wildfires take a heavy toll on human health worldwide. Climate change may increase the risk of wildfire frequency. Therefore, in view of adapted preventive actions, there is an urgent need to further understand the health effects and public awareness of wildfires. We conducted a systematic review of non-accidental health impacts of wildfire and incorporated lessons learned from recent experiences. Based on the literature, various studies have established the relationship between one of the major components of wildfire, particulate matter (particles with diameter less than 10 µm (PM10) and less than 2.5 µm (PM2.5)) and cardiorespiratory symptoms in terms of Emergency Rooms visits and hospital
Municipal Solid Waste landfilling is the most common waste elimination in the developing countrie... more Municipal Solid Waste landfilling is the most common waste elimination in the developing countries in general and particularly in Côte d’Ivoire. However, gaseous emissions from waste landfilled constitute an environment and human health concern by contributing to greenhouse gas effects, odour problems, explosion and fire hazards as well as sources of air pollution. In this study, methane emissions rates from Akouédo (Abidjan) landfill have been estimated using three theoretical models such as Landfill Gas Emission Model (LandGEM, version 3.02), Intergovernmental Panel on Climate Change (IPCC) waste model and Solid Waste Emissions Estimation Tool (SWEET). Two types of parameters have been used to estimate methane emissions, default parameters and site-specific parameters. The results of simulations of the three models are compared as well as the results from their default and sitespecific parameters. Results show that LandGEM simulations using both default and site-specific parameter...
Recent simulations have shown a gap between observed and modeled aerosol optical depths above the... more Recent simulations have shown a gap between observed and modeled aerosol optical depths above the Guinean Gulf in West Africa, assuming the possible role of flaring emissions which are really important in this area and not accounted for in this work. It can be expected that these emissions also impact regional air quality and health. In this presentation, recent developments on flaring emission inventories for aerosols and gases obtained from DMSP satellite for the years 1990-2012 and validated over Nigeria will be presented and discussed in terms of temporal and spatial variability. By introducing such emission inventories in RegCM regional climatic model in addition to other anthropogenic sources (traffic, domestic fires, industries, charcoal making, biomass burning..) we will study the relative contributions of the different emissions sources on air quality, climate and health.
Road traffic emission inventories based on bottom-up methodology, are calculated for each road se... more Road traffic emission inventories based on bottom-up methodology, are calculated for each road segment from fuel consumption and traffic volume data obtained during field measurements in Yopougon. High emissions of black carbon (BC) from vehicles are observed at major road intersections, in areas surrounding industrial zones and on highways. Highest emission values from road traffic are observed for carbon monoxide (CO) (14.8 t/d) and nitrogen oxides (NOx) (7.9 t/d), usually considered as the major traffic pollution tracers. Furthermore, peak values of CO emissions due to personal cars (PCs) are mainly linked to the old age of the vehicle fleet with high emission factors. The highest emitting type of vehicle for BC on the highway is PC (70.2%), followed by inter-communal taxis (TAs) (13.1%), heavy vehicles (HVs) (9.8%), minibuses (GBs) (6.4%) and intra-communal taxis (WRs) (0.4%). While for organic carbon (OC) emissions on the main roads, PCs represent 46.7%, followed by 20.3% for W...
There are very few African regional inventories providing biofuel and fossil fuel emissions. With... more There are very few African regional inventories providing biofuel and fossil fuel emissions. Within the framework of the DACCIWA project, we have developed an African regional anthropogenic emission inventory including the main African polluting sources (wood and charcoal burning, charcoal making, trucks, cars, buses and two-wheeled vehicles, open waste burning, and flaring). To this end, a database on fuel consumption and emission factors specific to Africa was established using the most recent measurements. New spatial proxies (road network, power plant geographical coordinates) were used to convert national emissions into gridded inventories at a 0.1 • × 0.1 • spatial resolution. This inventory includes carbonaceous particles (black and organic carbon) and gaseous species (CO, NO x , SO 2 and NMVOCs) for the period 1990-2015 with a yearly temporal resolution. We show that all pollutant emissions are globally increasing in Africa during the period 1990-2015 with a growth rate of 95 %, 86 %, 113 %, 112 %, 97 % and 130 % for BC, OC, NO x , CO, SO 2 and NMVOCs, respectively. We also show that Western Africa is the highest emitting region of BC, OC, CO and NMVOCs, followed by Eastern Africa, largely due to domestic fire and traffic activities, while Southern Africa and Northern Africa are the highest emitting regions of SO 2 and NO x due to industrial and power plant sources. Emissions from this inventory are compared to other regional and global inventories, and the emissions uncertainties are quantified by a Monte Carlo simulation. Finally, this inventory highlights key pollutant emission sectors in which mitigation scenarios should focus on. The DACCIWA inventory (
A number of campaigns have been carried out to establish the emission factors of pollutants from ... more A number of campaigns have been carried out to establish the emission factors of pollutants from fuel combustion in West Africa, as part of work package 2 ("Air Pollution and Health") of the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) FP7 program. Emission sources considered here include wood (hevea and iroko) and charcoal burning, charcoal making, open trash burning, and vehicle emissions, including trucks, cars, buses and two-wheeled vehicles. Emission factors of total particulate matter (TPM), elemental carbon (EC), primary organic carbon (OC) and volatile organic compounds (VOCs) have been established. In addition, emission factor measurements were performed in combustion chambers in order to reproduce field burning conditions for a tropical hardwood (hevea), and obtain particulate emission factors by size (PM 0.25 , PM 1 , PM 2.5 and PM 10). Particle samples were collected on quartz fiber filters and analyzed using gravimetric method for TPM and thermal methods for EC and OC. The emission factors of 58 VOC species were determined using offline sampling on a sorbent tube. Emission factor results for two species of tropical hardwood burning of EC, OC and TPM are 0.98 ± 0.46 g kg −1 of fuel burned (g kg −1), 11.05 ± 4.55 and 41.12 ± 24.62 g kg −1 , respectively. For traffic sources, the highest emission factors among particulate species are found for the two-wheeled vehicles with two-stroke engines (2.74 g kg −1 fuel for EC, 65.11 g kg −1 fuel for OC and 496 g kg −1 fuel for TPM). The largest VOC emissions are observed for two-stroke two-wheeled vehicles, which are up to 3 times higher than emissions from light-duty and heavyduty vehicles. Isoprene and monoterpenes, which are usually associated with biogenic emissions, are present in almost all anthropogenic sources investigated during this work and could be as significant as aromatic emissions in wood burning (1 g kg −1 fuel). EC is primarily emitted in the ultrafine fraction, with 77 % of the total mass being emitted as particles smaller than 0.25 µm. The particles and VOC emission factors obtained in this study are generally higher than those in the literature whose values are discussed in this paper. This study underlines the important role of in situ measurements in deriving realistic and representative emission factors.
A regional fossil fuel and biofuel emission inventory for particulates has been developed for Afr... more A regional fossil fuel and biofuel emission inventory for particulates has been developed for Africa at a resolution of 0.25° x 0.25° for the year 2005. The original database of Junker and Liousse (2008) was used after modification for updated regional fuel consumption and emission factors. Consumption data were corrected after direct inquiries conducted in Africa, including a new emitter
h i g h l i g h t s Review of methods used to assess wildfire exposure and related health impact.... more h i g h l i g h t s Review of methods used to assess wildfire exposure and related health impact. Discussion of uncertainties of exposure assessment in the literature. Application of methods which allowed to have emissions at local area.
International Journal of Environmental Research and Public Health, 2014
Wildfires take a heavy toll on human health worldwide. Climate change may increase the risk of wi... more Wildfires take a heavy toll on human health worldwide. Climate change may increase the risk of wildfire frequency. Therefore, in view of adapted preventive actions, there is an urgent need to further understand the health effects and public awareness of wildfires. We conducted a systematic review of non-accidental health impacts of wildfire and incorporated lessons learned from recent experiences. Based on the literature, various studies have established the relationship between one of the major components of wildfire, particulate matter (particles with diameter less than 10 µm (PM 10) and less than 2.5 µm (PM 2.5)) and cardiorespiratory symptoms in terms of Emergency Rooms visits and hospital
Emissions of gases and particles from the combustion of fossil fuels and biofuels in Africa are e... more Emissions of gases and particles from the combustion of fossil fuels and biofuels in Africa are expected to increase significantly in the near future due to the rapid growth of African cities and megacities. There is currently no regional emissions inventory that provides estimates of anthropogenic combustion for the African continent. This work provides a quantification of the evolution of African combustion emissions from 2005 to 2030, using a bottom-up method. This inventory predicts very large increases in black carbon, organic carbon, CO, NO x , SO 2 and non-methane hydrocarbon emissions if no emission regulations are implemented. This paper discusses the effectiveness of scenarios involving certain fuels, specific to Africa in each activity sector and each region (western, eastern, northern and southern Africa), to reduce the emissions. The estimated trends in African emissions are consistent with emissions provided by global inventories, but they display a larger range of values. African combustion emissions contributed significantly to global emissions in 2005. This contribution will increase more significantly by 2030: organic carbon emissions will for example make up 50% of the global emissions in 2030. Furthermore, we show that the magnitude of African anthropogenic emissions could be similar to African biomass burning emissions around 2030.
Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of clima... more Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of climate at Lamto (6.13°N, 5.02°W) in Côte d’Ivoire. A combined pluviothermal index is used to identify climate regions of West Africa. The interdecadal change of the climate is analyzed along with a discussion on the West African Monsoon (WAM) circulation. The impact of vegetation is also analyzed. It is shown that Lamto has mainly a subhumid climate but, in some particular years, this area has a humid climate. Two decades (1962–1971 and 2002–2011) exhibit rainfall excess and the last three ones (1972–1981, 1982–1991, and 1992–2001) show a rainfall deficit that affected West Africa in the early 1970s. The meridional wind field from 1000 hPa to 700 hPa is used to study the WAM variability. The level of the WAM is the lowest (~860–890 hPa) during the active period of the northern wind coming from the Sahara desert (November–February). During 1962–1971 and 2007–2009, the depth of the monsoon at ...
Real time measurements of Black Carbon (BC) in PM 2.5 aerosols were performed during AMMA and POL... more Real time measurements of Black Carbon (BC) in PM 2.5 aerosols were performed during AMMA and POLCA programs, between 2005 and 2010 in Cotonou (Benin), Dakar (Senegal), Bamako (Mali), and Yaounde (Cameroon). Indeed, BC was chosen as a metric because of its interest as an urban pollutant. The instrumented sites are representative of the traffic source. At Dakar, BC concentrations are high from November to April (13,000 AE 3500 ng m À3) and lower from May to September (8000 AE 3200 ng m À3). In dry season (NovembereApril), high BC concentrations occurred as a result of northeasterly long-range transport of polluted air masses over West Africa, in addition to local emissions. However, during wet season (MayeSeptember) reduced traffic levels, school vacations and wet deposition processes contribute to lower BC concentration levels. Measured diurnal BC peak concentrations, at all sites, mainly occur during morning and evening rush-hour periods, indicating the paramount role of traffic. Highest values are observed between 5e9 a.m. and from 5 p.m. to 9 p.m. depending on the site, while lowest are occurred at night time and middle afternoon when activities of the population are reduced. BC source apportionment from absorption measurements also confirmed the relative importance of traffic (88%) versus biomass burning (12%). Also, BC measurements were functions of days of the week, with highest values occurring on Fridays and lowest ones on Sundays. Spatial variations associated to BC levels are very different from one site to another, revealing different types of sources with strong variations at the regional scale. It appears that mean BC concentrations in Dakar are lower by a factor of two, compared to those observed in Bamako, but remain higher than in some other West African sites (e.g. Cotonou, Yaounde). Overall, BC concentrations in our different sites are comparable to reported European and Asian megacity levels. Finally, using measured BC/PM 2.5 ratios, we have estimated PM 2.5 mass concentrations in Dakar from June 2008 to June 2009 to be 44.4 AE 14.3 mg m À3 , well above the WHO (2005) threshold of 10 mg m À3. This paper clearly highlights high pollution levels in West African large cities, with potential important impacts on the health of the regional population.
This pollution mainly derives from road traffic emissions with, in some capitals (e.g. Cotonou), ... more This pollution mainly derives from road traffic emissions with, in some capitals (e.g. Cotonou), the strong contribution of two-wheel vehicles. Two key questions arise: are presently available emission inventories (e.g. Junker, C., Liousse, C., 2008. A global emission inventory of carbonaceous aerosol from historic records of fossil fuel and biofuel consumption for the period 1860e1997.
African biomass burning emission inventories for gaseous and particulate species have been constr... more African biomass burning emission inventories for gaseous and particulate species have been constructed at a resolution of 1 km by 1km with daily coverage for the 2000-2007 period. These inventories are higher than the GFED2 inventories, which are currently widely in use. Evaluation specifically focusing on combustion aerosol has been carried out with the ORISAM-TM4 global chemistry transport model which includes a detailed aerosol module. This paper compares modeled results with measurements of surface BC concentrations and scattering coefficients from the AMMA Enhanced Observations period, aerosol optical depths and single scattering albedo from AERONET sunphotometers, LIDAR vertical distributions of extinction coefficients as well as satellite data. Aerosol seasonal and interannual evolutions over the 2004-2007 period observed at regional scale and more specifically at the Djougou (Benin) and Banizoumbou (Niger) AMMA/IDAF sites are well reproduced by our global model, indicating that our biomass burning emission inventory appears reasonable.
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