Biomass burning aerosol emissions from vegetation fires: particle number and mass emission factors and size distributions Biogeochemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, 55020 Mainz, Germany
Received: 06 July 2009 – Published in Atmos. Chem. Phys. Discuss.: 14 August 2009 Abstract. Aerosol emissions from vegetation fires have a large impact on air quality
and climate. In this study, we use published experimental data and different
fitting procedures to derive dynamic particle number and mass emission
factors (EFPN, EFPM) related to the fuel type, burning conditions
and the mass of dry fuel burned, as well as characteristic CO-referenced
emission ratios (PN/CO, PM/CO). Moreover, we explore and characterize the
variability of the particle size distribution of fresh smoke, which is
typically dominated by a lognormal accumulation mode with count median
diameter around 120 nm (depending on age, fuel and combustion efficiency),
and its effect on the relationship between particle number and mass emission
Revised: 28 December 2009 – Accepted: 10 January 2010 – Published: 09 February 2010
For the particle number emission factor of vegetation fires, we found no
dependence on fuel type and obtained the following parameterization as a
function of modified combustion efficiency (MCE): EFPN=34×1015×(1−MCE) kg−1±1015 kg−1 with regard to dry
fuel mass (d.m.). For the fine particle mass emission factors (EFPM) we
obtained (86–85×MCE) g kg−1±3 g kg−1 as an average for all
investigated fires; (93–90×MCE) g kg−1±4 g kg−1 for forest;
(67–65×MCE) g kg−1±2 g kg−1 for savanna; (63–62×MCE) g kg−1±1 g kg−1 for grass.
For the PN/CO emission ratio we obtained an average of (34±16) cm−3 ppb−1
exhibiting no systematic dependence on fuel type or
combustion efficiency. The average PM/CO emission ratios were (0.09±0.04) g g−1
for all investigated fires; (0.13±0.05) g g−1 for forest; (0.08±0.03) g g−1 for savanna; and
(0.07±0.03) g g−1 for grass.
The results are consistent with each other, given that particles from forest
fires are on average larger than those from savanna and grass fires. This
assumption and the above parameterizations represent the current state of
knowledge, but they are based on a rather limited amount of experimental
data which should be complemented by further measurements. Nevertheless, the
presented parameterizations appear sufficiently robust for exploring the
influence of vegetation fires on aerosol particle number and mass
concentrations in regional and global model studies.
Citation: Janhäll, S., Andreae, M. O., and Pöschl, U.: Biomass burning aerosol emissions from vegetation fires: particle number and mass emission factors and size distributions, Atmos. Chem. Phys., 10, 1427-1439, doi:10.5194/acp-10-1427-2010, 2010.