Aerosol and VOC emission factor measurements for African anthropogenic sources

Abstract

Abstract. 15A 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 and charcoal burning, charcoal making, open waste burning, and vehicles including trucks, cars, buses and two-wheeled vehicles. Emission factors of total particulate matter, black carbon, primary organic carbon and non-methane volatile organic compounds (NMVOC) have been 20established. In addition, emission factor measurements were performed in combustion chambers in order to reproduce field burning conditions for tropical hardwood, and obtain particulate emission factors by size (PM0.25, PM1, PM2.5 and PM10).Aerosol samples were collected on quartz filters and analysed using gravimetric and thermal methods. The emission factors of 50 NMVOC species were determined using systematic off-line sampling. Emission factors from wood burning for black carbon, organic carbon and total particulate matter were 0.8 ± 0.4 g/kg of dry matter (dm), 9.29 ± 3.82 g/kg dm and 34.54 ± 25 20.6 g/kg dm, respectively. From traffic sources, the highest emission factors for all particulate species were emitted from two wheeled vehicles with two-stroke engines (2.74 g/kg fuel for black carbon, 65.11 g/kg fuel for organic carbon and 496 g/kg fuel for total particulate matter). The emissions of NMVOCs were lower than those of particles for all sources aside from traffic. The largest NMVOC emissions were observed for two-stroke two-wheeled vehicles, which were up to three times higher than emissions from light-duty and heavy-duty vehicles. Isoprene and monoterpenes, which are usually associated with 30 biogenic emissions, were present in almost all anthropogenic source categories and could be as significant as aromatic emissions in wood burning (1 g/kg dm). Black carbon was primarily emitted in the ultrafine fraction, with 77% of the total mass being emitted as particles smaller than 0.25 µm. This study observed higher particle and NMVOC emission factors than Atmos. Chem. Phys. Discuss., https://doi

Mass concentration, optical depth and carbon composition of particulate matter in the major southern West African cities of Cotonou (Benin) and Abidjan (Côte d'Ivoire)

“…The emission factor (EF) for PM 2.5 and carbonaceous species depends on fuel type and combustion. Keita et al (2017) give a factor of 2 between EF and hard and soft wood. Moreover Shen et al (2013) show that EF for PM and OC can be a factor of 2 higher for humid wood, which can be the case during season W, W and D as wood is stored outside.…”