Biogenic Secondary Organic Aerosol Formation
Michael Boy
ASP / ACD / NCAR
What is the main process concerning SOA What is the main process concerning SOA formation ?formation ?
Nucleation !Condensational
growth !
We suggest that the growth of clusters to a detectable sice is restricted by the availability of condensable vapour. Observations of atmospheric particle formation and growth from a continental and a coastal site support this hypothesis, including that a growth process including ternary nucleation is likely to be responsible for the formation of CCN.
Kulmala et al., Nature 2000
M. Kulmala et at., Aerosol Science 35 (2004), p. 143-176
Where do we observe SOA formation ?
How many SOA formation events per year ?How many SOA formation events per year ?
Hyytiälä, Finland 1996 - 2003
0
20
40
60
80
100
120
140
1996 1997 1998 1999 2000 2001 2002 2003
Year
Nr.
of even
ts
Seasonal trend of SOA formation events ?
M. Kulmala et at., Aerosol Science 35 (2004), p. 143-176
Rural area in Finland
Rural area in Germany
Urban area in USA
Is SOA formation a local effect ?
(Stratmann et al.,
ACP 2003, Vol. 3)
(Stratmann et al., ACP 2003)
Vertical distribution of new formed particles
How fast do the new formed particles grow ?How fast do the new formed particles grow ?
Kulmala et at., Aerosol Science 2004, Vol. 35
Polar regions: 0.1 nm h-1
Coastal areas: 200 nm h-1
How many particles are produced per time ?
Urban areas:
up to 100 # cm-3 s-1
Coastal zones:
up to 104-105 # cm-3 s-1
Industrial plumes:
up to 104-105 # cm-3 s-1
________________________________________________________________________________________
University of Helsinki
3 nm
Free troposphere
Mixed layer
1 nm
Formation of TSCs
Formation of TSCs
Binary nucleation: H2SO4 + H2O
Ternary nucleation: H2SO4 + NH3 + H2O
Ion induced nucleation
Nucleation of organics
________________________________________________________________________________________
University of Helsinki
3 nm
Free troposphere
Mixed layer
Production of condensable
vapours
Ozone
1 nm
Formation of TSCs
Production of condensable vapours
Sulphuric acid
Monotepenes reaction products
Sesquiterpenes reaction products
????
________________________________________________________________________________________
University of Helsinki
3 nm
Free troposphere
Condensation
Coagulation
Deposition
Mixed layer
Production of condensable
vapours
Ozone
Condensation &Coagulation
1 nm
Formation of TSCs
Weber et al., JGR (1997) 102
Fiedler et al., ACPD (2005)
Sulfuric acid and nucleation mode particles ?
Date
Growth rate GR(H2SO4)
DMPS H2SO4 / GR(DMPS)
[nm h-1 ] [nm h-1 ] [%]
19.3.2003 1,0 0,06 6,1
20.3.2003 1,5 0,15 10,2
21.3.2003 2,6 0,24 9,1
25.3.2003 2,5 0,15 6,1
26.3.2003 3,6 0,31 8,6
29.3.2003 3,6 0,17 4,8
31.3.2003 3,5 0,23 6,7
2.4.2003 2,4 0,40 16,9
3.4.2003 3,8 0,28 7,3
6.4.2003 1,8 0,16 8,7
7.4.2003 2,9 0,39 13,5
Average 2,7 0,2 8,9
Intermedia step for global models
Influence on CCN
UHMA (University of
Helsinki Multicomponent
Aerosol code)Chemistry subroutine
(67 species)
BLMARC
(1-dimensionsal model)
Emission scheme for different biospheres
Extended organic chemistry scheme
Condensation of organics
Information on the secrets
of SOA formation
Ion induced nucleation
1-D-Model trajectory
Thanks !!!
Top Related