Particle Number Size Distributions at an Urban Site in southern Sweden: Estimates of the Contribution of Urban Particle Sources Erik Swietlicki 1 , Andreas Massling 1 , Ingela Dahlberg 1 , Jakob Löndahl 1 , Adam Kristensson 2 , Henric Nilsson 3 , Susanna Gustafsson 3 and Matthias Ketzel 4 1 Division of Nuclear Physics, Lund University, Lund, Sweden 2 Department of Chemistry, Copenhagen University, Copenhagen, Denmark 3 Environment and Health Protection Board, City of Malmö, Malmö, Sweden 4 Department of Atmospheric Environment, National Environmental Research Institute, Roskilde, Denmark Research funded by the Swedish FORMAS Paper 8A1, Session 8, IAC 2006
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Particle Number Size Distributions at an Urban Site in southern Sweden: Estimates of the Contribution of Urban Particle Sources Erik Swietlicki 1, Andreas.
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Particle Number Size Distributions at an Urban Site in southern Sweden:
Estimates of the Contribution of Urban Particle Sources
Erik Swietlicki1, Andreas Massling1, Ingela Dahlberg1, Jakob Löndahl1, Adam Kristensson2, Henric Nilsson3, Susanna
Gustafsson3 and Matthias Ketzel4
1Division of Nuclear Physics, Lund University, Lund, Sweden2Department of Chemistry, Copenhagen University, Copenhagen, Denmark3Environment and Health Protection Board, City of Malmö, Malmö, Sweden
4Department of Atmospheric Environment, National Environmental Research Institute, Roskilde, Denmark
Research funded by the Swedish FORMAS
Paper 8A1, Session 8, IAC 2006
Motivation – Human Health
•CAFE estimates that fine particles (PM2.5) and ozone combined are responsible for 370,000 premature deaths each year in EU25, and the loss of 3.6 millions years of life annually.
(CAFE: Impact Assessment of the Thematic Strategy on Air Pollution and the Directive on “Ambient Air Quality and Cleaner Air for Europe”, SEC(2005)1133, Brussels, 21 Sept. 2005 (http://www.cafe-cba.org/)
•WHO estimates that exposure to fine particulate matter in outdoor air leads to about 100 000 deaths (and 725 000 years of life lost) annually in Europe. (WHO, World Health Report 2002, Geneva)
• For Sweden, Forsberg et al. (2005) estimated that the current population exposure to PM10 results in 5000 premature deaths annually.
Urban Roof-top – Regional BackgroundVavihill – Malmö
Urban site(Malmö)
Backgrund(Vavihill)
Malmö City Contribution to the Urban Roof-top Aerosol
Mode GMDs: 8 nm, 38-39 nm, 95-100 nmFresh aerosol (traffic, ships,..) + processed within city limits
Weekdays Weekends
Malmö CityContribution
MalmöCity
Contr.
Malmö City Contribution to the Urban Roof-top Aerosol
Mode GMDs: 8 nm, 38-39 nm, 95-100 nmFresh aerosol (traffic, ships,..) + processed within city limits
Malmö CityContribution
Weekdays July 2005
Malmö CityContribution
Traffic
Ship?
Harbour Inlet
Tetramodal distribution
0
5000
10000
15000
20000
25000
30000
35000
10 100 1000
Dp
dN
/dlo
gD
p
Original distr.
Mode 1
Mode 2
Mode 3
Mode 4
Mode 1-4
Mode 1
N1(cm-3)
CMD1 (nm)
Sigma1
12500 8 1.64
Mode 2
N2(cm-3)
CMD2 (nm)
Sigma2
11100 47 1.45
Mode 3
N3(cm-3)
CMD3 (nm)
Sigma3
2300 115 1.6
Mode 4
N4(cm-3)
CMD4 (nm)
Sigma4
5100 24 1.6
The urban contribution seems to be from road traffic plus ship movements in the harbour.Could the size shift from 25 nm to 40 nm be caused by aerosol dynamics instead?
Method
Ketzel, M. and Berkowicz, R. (2005): Multi-plume aerosol dynamics and transport model for urban scale particle pollution. Atmospheric Environment 39, 3407-3420.
AERO3 Model (E. Vignati, JRC)
InputAssumptions:The background size distribution at Vavihill (3-modal)The estimated traffic emission size distribution (4-modal)Average wind speed = 4 m/sEmission density for Malmö = 230 (pt/cm3) m/s
Modelling Urban Aerosol Dynamics
Question: Can particles grow from 25 to 40 nm in the urban background?
0.01 0.1d p in µm
0.0x10 0
4.0x10 3
8.0x10 3
1.2x10 4
1.6x10 4
2.0x10 4
dN
/dlo
g(d
p)
AER O 3
t= 0 , 1 , 3 , 5 H O U R S
Regional background, Urban Traffic Emissions and Dilution,No Aerosol Removal process
Modelling Urban Aerosol Dynamics
0 h
1 h
3 h
5 h
Emissions
0.01 0.1d p in µm
0.0x10 0
4.0x10 3
8.0x10 3
1.2x10 4
1.6x10 4
2.0x10 4
dN
/dlo
g(d
p)
AER O 3
t= 0 , 1 , 3 , 5 H O U R S
0.01 0.1d p in µm
0.0x10 0
4.0x10 3
8.0x10 3
1.2x10 4
1.6x10 4
dN
/dlo
g(d
p)
AER O 3
Regional background, Urban Traffic Emissions and Dilution,No Aerosol Removal process
Regional background, Traffic Emissions, Dilution, Coagulation,Deposition with u*=1.33 m/s, No condensation
Modelling Urban Aerosol Dynamics
0 h
1 h
3 h
5 h
0.01 0.1d p in µm
0.0x10 0
4.0x10 3
8.0x10 3
1.2x10 4
1.6x10 4
2.0x10 4
dN
/dlo
g(d
p)
AER O 3
t= 0 , 1 , 3 , 5 H O U R S
0.01 0.1d p in µm
0.0x10 0
4.0x10 3
8.0x10 3
1.2x10 4
1.6x10 4
dN
/dlo
g(d
p)
AER O 3
0.01 0.1d p in µm
0x10 0
4x10 3
8x10 3
1x10 4
2x10 4
dN
/dlo
g(d
p)
AER O 3
Regional background, Urban Traffic Emissions and Dilution,No Aerosol Removal process
Regional background, Traffic Emissions, Dilution, CoagulationDeposition with u*=1.33 m/s, No condensation