Advanced

Primary versus secondary contributions to particle number concentrations in the European boundary layer

Reddington, C. L.; Carslaw, K. S.; Spracklen, D. V.; Frontoso, M. G.; Collins, L.; Merikanto, J.; Minikin, A.; Hamburger, T.; Coe, H. and Kulmala, M., et al. (2011) In Atmospheric Chemistry and Physics 11(23). p.12007-12036
Abstract
It is important to understand the relative contribution of primary and secondary particles to regional and global aerosol so that models can attribute aerosol radiative forcing to different sources. In large-scale models, there is considerable uncertainty associated with treatments of particle formation (nucleation) in the boundary layer (BL) and in the size distribution of emitted primary particles, leading to uncertainties in predicted cloud condensation nuclei (CCN) concentrations. Here we quantify how primary particle emissions and secondary particle formation influence size-resolved particle number concentrations in the BL using a global aerosol microphysics model and aircraft and ground site observations made during the May 2008... (More)
It is important to understand the relative contribution of primary and secondary particles to regional and global aerosol so that models can attribute aerosol radiative forcing to different sources. In large-scale models, there is considerable uncertainty associated with treatments of particle formation (nucleation) in the boundary layer (BL) and in the size distribution of emitted primary particles, leading to uncertainties in predicted cloud condensation nuclei (CCN) concentrations. Here we quantify how primary particle emissions and secondary particle formation influence size-resolved particle number concentrations in the BL using a global aerosol microphysics model and aircraft and ground site observations made during the May 2008 campaign of the European Integrated Project on Aerosol Cloud Climate Air Quality Interactions (EUCAARI). We tested four different parameterisations for BL nucleation and two assumptions for the emission size distribution of anthropogenic and wildfire carbonaceous particles. When we emit carbonaceous particles at small sizes (as recommended by the Aerosol Inter-comparison project, AEROCOM), the spatial distributions of campaign-mean number concentrations of particles with diameter >50 nm (N-50) and >100 nm (N-100) were well captured by the model (R-2 >= 0.8) and the normalised mean bias (NMB) was also small (-18% for N-50 and -1% for N-100). Emission of carbonaceous particles at larger sizes, which we consider to be more realistic for low spatial resolution global models, results in equally good correlation but larger bias (R-2 >= 0.8, NMB = -52% and -29%), which could be partly but not entirely compensated by BL nucleation. Within the uncertainty of the observations and accounting for the uncertainty in the size of emitted primary particles, BL nucleation makes a statistically significant contribution to CCN-sized particles at less than a quarter of the ground sites. Our results show that a major source of uncertainty in CCN-sized particles in polluted European air is the emitted size of primary carbonaceous particles. New information is required not just from direct observations, but also to determine the "effective emission size" and composition of primary particles appropriate for different resolution models. (Less)
Please use this url to cite or link to this publication:
author
, et al. (More)
(Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Atmospheric Chemistry and Physics
volume
11
issue
23
pages
12007 - 12036
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • wos:000298134300006
  • scopus:83455231344
ISSN
1680-7324
DOI
10.5194/acp-11-12007-2011
language
English
LU publication?
yes
id
958cd4bd-b2ff-4f70-b898-3171a814caa7 (old id 2494349)
date added to LUP
2012-05-15 15:45:22
date last changed
2017-11-12 03:09:07
@article{958cd4bd-b2ff-4f70-b898-3171a814caa7,
  abstract     = {It is important to understand the relative contribution of primary and secondary particles to regional and global aerosol so that models can attribute aerosol radiative forcing to different sources. In large-scale models, there is considerable uncertainty associated with treatments of particle formation (nucleation) in the boundary layer (BL) and in the size distribution of emitted primary particles, leading to uncertainties in predicted cloud condensation nuclei (CCN) concentrations. Here we quantify how primary particle emissions and secondary particle formation influence size-resolved particle number concentrations in the BL using a global aerosol microphysics model and aircraft and ground site observations made during the May 2008 campaign of the European Integrated Project on Aerosol Cloud Climate Air Quality Interactions (EUCAARI). We tested four different parameterisations for BL nucleation and two assumptions for the emission size distribution of anthropogenic and wildfire carbonaceous particles. When we emit carbonaceous particles at small sizes (as recommended by the Aerosol Inter-comparison project, AEROCOM), the spatial distributions of campaign-mean number concentrations of particles with diameter >50 nm (N-50) and >100 nm (N-100) were well captured by the model (R-2 >= 0.8) and the normalised mean bias (NMB) was also small (-18% for N-50 and -1% for N-100). Emission of carbonaceous particles at larger sizes, which we consider to be more realistic for low spatial resolution global models, results in equally good correlation but larger bias (R-2 >= 0.8, NMB = -52% and -29%), which could be partly but not entirely compensated by BL nucleation. Within the uncertainty of the observations and accounting for the uncertainty in the size of emitted primary particles, BL nucleation makes a statistically significant contribution to CCN-sized particles at less than a quarter of the ground sites. Our results show that a major source of uncertainty in CCN-sized particles in polluted European air is the emitted size of primary carbonaceous particles. New information is required not just from direct observations, but also to determine the "effective emission size" and composition of primary particles appropriate for different resolution models.},
  author       = {Reddington, C. L. and Carslaw, K. S. and Spracklen, D. V. and Frontoso, M. G. and Collins, L. and Merikanto, J. and Minikin, A. and Hamburger, T. and Coe, H. and Kulmala, M. and Aalto, P. and Flentje, H. and Plass-Duelmer, C. and Birmili, W. and Wiedensohler, A. and Wehner, B. and Tuch, T. and Sonntag, A. and O'Dowd, C. D. and Jennings, S. G. and Dupuy, R. and Baltensperger, U. and Weingartner, E. and Hansson, H. -C. and Tunved, P. and Laj, P. and Sellegri, K. and Boulon, J. and Putaud, J. -P. and Gruening, C. and Swietlicki, Erik and Roldin, Pontus and Henzing, J. S. and Moerman, M. and Mihalopoulos, N. and Kouvarakis, G. and Zdimal, V. and Zikova, N. and Marinoni, A. and Bonasoni, P. and Duchi, R.},
  issn         = {1680-7324},
  language     = {eng},
  number       = {23},
  pages        = {12007--12036},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Atmospheric Chemistry and Physics},
  title        = {Primary versus secondary contributions to particle number concentrations in the European boundary layer},
  url          = {http://dx.doi.org/10.5194/acp-11-12007-2011},
  volume       = {11},
  year         = {2011},
}