Dynamics-aerosol-chemistry-cloud interactions in West Africa
Research Publications
Air Pollution and Health
01 June 2018
Particle and VOC emission factor measurements for anthropogenic sources in West Africa
Publication: Atmos. Chem. Phys., 18, 7691-7708 ()
DOI Number: 10.5194/acp-18-7691-2018
Author: Sekou Keita, Cathy Liousse, Véronique Yoboué, Pamela Dominutti, Benjamin Guinot, Eric-Michel Assamoi, Agnès Borbon, Sophie L. Haslett, Laetitia Bouvier, Aurélie Colomb, Hugh Coe, Aristide Akpo, Jacques Adon, Julien Bahino, Madina Doumbia, Julien Djossou, Corinne Galy-Lacaux, Eric Gardrat, Sylvain Gnamien, Jean F. Léon, Money Ossohou, E. Touré N’Datchoh, and Laurent Roblou
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 (PM0:25,
PM1, PM2:5 and PM10). 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 0.980.46 g kg??1 of fuel burned (g kg??1), 11.054.55
and 41.1224.62 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.