GAW Report No. 205 - IGAC Project

CHAPTER 7 – OVERVIEW OF INTERNATIONAL COLLABORATIVE RESEARCH ACTIVITIES7.10 INTEGRATED FOCUS ON WEST AFRICAN CITIESC. Liousse (1) , C. Galy-Lacaux (1) , E. Assamoi (1) , A. Ndiaye (2) , B. Diop (3) , H. Cachier (4) , T. Doumbia (1, 2) ,P. Gueye (2) , N. Marchand (5) , A. Ehgere (5) , A. Baeza (6) , S. Val (6) , I. George (6) , V. Yoboué (7) , L. Sigha (8) ,J.P. Lacaux (1) , B. Guinot (1) , J.F. Léon (1) , R. Rosset (1) , P. Castéra (1) , E. Gardrat (1) , C. Zouiten (9) , C. Jambert (1) ,A. Diouf (2) , O. Koita (3) , I. Annesi-Maesano (10) , A. Didier (11) , S. Audry (9) , A. Konaré (7)(1) Laboratoire d'Aérologie, UMR 5560 CNRS/UPS, Toulouse, France(2) Université C. A. Diop, Dakar, Sénégal(3) Université de Bamako, Mali(4) LSCE, Gif sur Yvette, France(5) LCP, Université d’Aix Marseille, Marseille, France(6) LCTC Université Paris Diderot-Paris 7, France(7) LAPA, Université d’Abidjan, Ivory Coast(8) CRH, Yaoundé, Cameroon(9) LMTG, Toulouse, France(10) Faculté de Médecine Saint-Antoine, Paris, France(11) Hôpital Larrey, Toulouse, FranceIntegrated Focus on West African cities (Cotonou, Bamako, Dakar, Ouagadougou, Abidjan,Niamey): Emissions, Air Quality, and Health Impacts of gases and aerosols in the frame ofAMMA and POLCA international programmes.West African cities are largely devoid of dedicated air quality monitoring stations, togetherwith no significant application of regulations. However fossil fuel and biofuel emissions of gases andparticles are highly emitted from traffic, transportation, domestic fires, wastes, tailings and industrialactivities. These emissions result in very poor still degrading air quality, exacerbated by the weatherand climate conditions, as can be readily realized on site. Clearly, this picture is still darkening dueto rapid sprawling urban growth into African megacities. Ensuing air quality degradation thus raisessevere public health problems such as respiratory and cardiovascular ailments.The POLlution in the African Capitals (POLCA) programme under the IDAF (IGAC DEBITSAfrica) framework jointly with the Laboratoire d'Aérologie (LA) as well as several Africanlaboratories took place in eight African capitals (Abidjan, Dakar, Bamako, Niamey, Ouagadougou,Bangui, Brazzaville, Yaounde). The preliminary results have highlighted the pressing urbanpollution problem in West Africa. As shown in Figure 15, measurements showed highconcentrations of NO 2 , SO 2 , etc. that regularly exceed the WHO air quality limits [Liousse andGaly-Lacaux, 2010].Within the African Monsoon Multidisciplinary Analysis (AMMA) and MOUSSON programmes(2005 - 2009), field studies were organized for the short term (May 2005) in Cotonou, Benin and forthe long term (2007-2009) in Ouagadougou (Burkina Faso) focusing on gas and aerosolconcentration measurements. These programmes have also revealed quite high particulate matterlevels. In addition, combustion emission inventories have been developed for African fossil andbiofuel emission sources [Assamoi and Liousse, 2010] for 2005 and 2030 (Figure 18).This context has proven to offer a unique opportunity to develop the POLCA programme intoa trans-disciplinary study between emissions, air quality and health impacts in West African cities.POLCA is now supported by the CORUS programmes(http://www.ird.fr/fr/science/dsf/corus/english_termes_reference.pdf) under the auspices of theFrench Ministry of Foreign Affairs (MFA), in partnership with African organizations.Within this framework, we have constructed a new integrated methodology that includes: (1)combustion emission characterizations; (2) joint experimental determination of gas concentrations(such as NO 2 , SO 2 , NH 3 , HNO 3 , O 3 , COV), size differentiated aerosol chemistry (total mass) (Figure16) [Doumbia et al., 2011], organic fraction (PAH), carbonaceous particles, inorganic particles(sulphates, nitrates…) and elements traces (iron, lead…) from ultrafine to coarse size fractions(Figure 17) [Val et al., 2011], as well as in vitro toxicological measurements (oxidative stress272