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  • 2008 Field measurements 1

    Field Measurements of organic aerosols

    Laboratory of Atmospheric Chemistry

    LAC :

    Head: Urs Baltensperger

    15 Scientists/Postdocs

    18 Phd students

    3 Groups

    - Gasphase and Aerosol chemistry

    - Aerosol physics

    - Ecosystem fluxes

  • 2008 Field measurements 2

    Field Measurements of organic aerosols

    Emission characterisation EC, OM, inorganic aerosol, elements, acids, gases, aerosol size AMS, SR-XRF, IC-MS, aethalometer

    Transformation Trace gas oxidation, SOA formation, gasphase-aerosol partitioning, aerosol processing Smogchamber, PTR-MS, AMS, gasphase instruments; Master Chemical mechanism

    gas phase organic aerosol, OA

    X (g) X (a)

    X (oligomer)

    X (aq)

    aqueous phase

    VOC OH HO2

    RO2 RO

    NO NO2

    NONO2

    O2

    HNO3

    NO2

    H2O2 HO2

    O2 reaction, decomposition or isomerisation

    ROOH

    HO2

    ROH + R-HO

    RO2 NO RONO2

    NO2

    RO2NO2

    hυ O3 O2

    Ambient Measurements EC, OM, inorganic aerosol, elements, acids, gases, aerosol size Mobile van, AMS, 14C, s-XRF, IC-MS, Aethalometer; statistical analyses

    Chemical Transport Modelling Particulate matter, ozone CAM-x, MM5, COSMO

  • 2008 Field measurements 3

    Field Measurements of organic aerosols

    Field experiments

    ♦Switzerland ♦Europe ♦Global

  • 2008 Field measurements 4

    Field Measurements of organic aerosols

    Locations with AMS Measurements

    Zürich (July/August and January)

    Reiden (February)

    Roveredo (March, December )

    Härkingen (May)

    Payerne (June, January)

    Massongex (December)

    JFJ (Winter, Summer)

    Rhine valley (February)

    Riviera (June)

    Milano (June)

    Mobile measurements

  • 2008 Field measurements 5

    Field Measurements of organic aerosols

    Average compositions in winter ( Zürich (January)

    Payerne (January)

    9%

    75%

    2%

    9%

    4% 1%

    18%

    45%

    8%

    16%

    9% 4%

    11%

    32%

    15%

    27%

    1%

    14%

    7%

    34%

    10%

    34%

    14% 1%

    7%

    36%

    9%

    34%

    13% 1%

    Black Carbon Organic mass Nitrate Sulfate Ammonium Chloride

    Roveredo (December)

    Massongex (December)

    Reiden (February)

  • 2008 Field measurements 6

    Field Measurements of organic aerosols

    Reiden, Winter

    ECfossil

    OCfossil nonfossil

    ECbiomass

    Jungfraujoch, Winter

    ECfossil

    OCfossil

    OCnonfossil

    ECbiomass

    Moleno, Winter

    OCfossil

    OCnonfossil ECfossil

    ECbiomass

    Zürich, Winter

    ECfossil

    OCfossil

    ECbiomass

    OCnonfossil

    Roveredo, Winter

    ECfossil

    OCfoss

    OCnonfossil

    ECbiomass

    Overview over the winter 14C analyses

  • 2008 Field measurements 7

    Field Measurements of organic aerosols

    ECbiomass/ECtot: Spatial distribution on 29.01.2006

    Bern 0.14

    Dübendorf 0.33

    Zürich 0.33

    Tänikon 0.40

    Payerne 0.42

    Basel 0.38

    Reiden 0.36

    Sedel 0.33

    Lausanne 0.19

    Härkingen 0.34

  • 2008 Field measurements 8

    Field Measurements of organic aerosols

    ECfossil 8%

    OCnonfossil 81%

    ECbiomass 11%

    ECfossil 13%

    OCfossil 12%

    OCnonfossil 66%

    ECbiomass 9%

    Holzverbrennung in Roveredo (GR), Januar 2005

    Roveredo (GR)

    06:00 – 14:00

    18:00 – 02:00

    Szidat et al., GRL, 2007

  • 2008 Field measurements 9

    Field Measurements of organic aerosols Aerosol mass spectra

    12

    8

    4

    0

    2001601208040 m/z

    12

    8

    4

    0

    % to

    to ta

    l o rg

    an ic

    s

    12

    8

    4

    0 12

    8

    4

    0 12

    8

    4

    0

    Levoglucosan

    Chestnut, poor burning

    Night Filter, March

    29

    29

    29 43

    43

    44 60

    60

    60 73

    73

    73

    115

    115

    137

    137

    167

    167

    167137

    Averaged nights, Dec 29

    43

    60 73 115 137 167

    29 44

    55 69 81 91

    Haerkingen, May

    Levoglucosan

    Wood burner (emissions) chestnut, very inefficient burning

    Night period in Roveredo in March, more than 80% of OC non-fossil

    Average in Roveredo over the whole December

    Mass spectra from a Motorway site in May

    Alfarra et al. ES&T (2007)

  • 2008 Field measurements 10

    Field Measurements of organic aerosols

    Dependence of light absorption as a function of wavelength measured by an aethalometer

    babs ∝ λ−α

    0.0

    2.0

    4.0

    6.0

    8.0

    10.0

    12.0

    350 450 550 650 750 850 950

    λ [nm]

    b a bs

    ( λ ) /

    b ab

    s ( 95

    0n m

    )

    Absorption exponent α: a measure of the strength of the spectral variation in aerosol light absorption

    Example power law fit (λ-2.0)

    Wood burninga λ-1.8 to -2.2

    Traffic, diesel soota,b λ-1.0 to -1.1

    a Kirchstetter et al. 2004 b Schnaiter et al. 2003 & 2005

    Sandradewi et al., Atmos. Environ., 2008

  • 2008 Field measurements 11

    Field Measurements of organic aerosols

    Aethalometer model to derive the contribution of woodburning and traffic to PM1

    Carbonaceous material (CM)

    Sandradewi et al., ES&T, 2008

  • 2008 Field measurements 12

    Field Measurements of organic aerosols

    Validation of aethalometer model

    Sandradewi et al., ES&T, 2008

    The variability of OM+BC can be explained at a site with negligible SOA

    Validation of aethalometer analysis with 14C analysis

    14C

    Aethalo meter

  • 2008 Field measurements 13

    Field Measurements of organic aerosols

    Average diurnal cycle of the carbonaceous material, OC/EC and wood burning versus traffic contributions

    Sandradewi et al., ES&T, 2008

  • 2008 Field measurements 14

    Field Measurements of organic aerosols

    Fractions of BC, OM, NO3, SO4 and NH4 and fossil and non-fossil contribution to EC and OC

    Nearly identical composition

    Black Carbon Organic mass Nitrate Sulfate Ammonium

    Black Carbon Organic mass Nitrate Sulfate Ammonium

    Z_meanPM10

    ECbb 4% ECfossil

    17%

    OCfossil 23%

    OCnonfossil 56%

    Z_meanPM10

    ECbb 4% ECfossil

    17%

    OCfossil 23%

    OCnonfossil 56%

    Zürich

    16% 30%

    14%

    6%

    34%

    Zürich

    16% 30%

    14%

    6%

    34%

    R_mean

    ECbb 5%

    ECfossil 17%

    OCfossil 22%

    OCnonfossil 56%

    R_mean

    ECbb 5%

    ECfossil 17%

    OCfossil 22%

    OCnonfossil 56%

    7%

    15%

    34% 11%

    33%

    Reiden

    7%

    15%

    34% 11%

    33%

    Reiden

    Urban background Highway/rural

  • 2008 Field measurements 15

    Field Measurements of organic aerosols

    70

    60

    50

    40

    30

    20

    10

    0

    M as

    s C

    on ce

    nt ra

    tio n

    (µ g

    m -3

    )

    29.01.2006 31.01.2006 02.02.2006 04.02.2006 06.02.2006 08.02.2006 10.02.2006 12.02.2006 Date & Time

    Organic Nitrate Ammonium Sulfate BC

    Reiden

    100

    80

    60

    40

    20Fr ac

    tio na

    l C on

    tr ib

    tio n

    %

    29.01.2006 31.01.2006 02.02.2006 04.02.2006 06.02.2006 08.02.2006 10.02.2006 12.02.2006 Date & Time

    Chemical composition of PM1 with high time resolution in Zürich and Reiden (Kt. Luzern)

    30

    25

    20

    15

    10

    5

    0

    M as

    s C

    on ce

    nt ra

    tio n

    (µ g

    m -3

    )

    08.01.2006 11.01.2006 14.01.2006 17.01.2006 20.01.2006 23.01.2006 Date & Time

    Zurich

    Organics Nitrate Sulphate Ammonium BC

    100

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