Sunset EC/OC analyzer Elemental, Organic and Total Carbon.
HPLC – PAD Levoglucosan.
AMS
14C for quantification of Modern and Fossil Carbon.
MWAA
Aerosol Absorption coefficient @ 5l: 375, 407, 532, 635 and 850nm.
Bibliography
Massabò D, Bernardoni V, Bove MC, Brunengo A, Cuccia E, Piazzalunga A, Prati P, Valli G, Vecchi R. (2013). A Multi-wavelength optical set-up for the characterization of carbonaceous particulate matter, Journal of Aerosol Science, 60, 34-46.
Massabò, D, Caponi, L, Bernardoni, V, Bove, MC, Brotto, P, Calzolai, G, Cassola, F, Chiari, M, Fedi, ME, Fermo, P, Giannoni, M, Lucarelli, F, Nava, S, Piazzalunga, A, Valli, G, Vecchi, R, Prati, P, (2015). Multi-wavelength optical determination of black and brown carbon in
atmospheric aerosols, Atmospheric Environment, 108, 1-12.
Massabò D, Caponi L, Bove, MC, Prati P, (2016). Brown Carbon and thermal-optical analysis: A correction based on optical multi-wavelength apportionment of atmospheric aerosols, Atmospheric Environment, 125, 119-125.
The effect of Brown Carbon on thermal-optical analysis: a correction based on
optical multi-wavelength analysis
D. Massabò
1, V. Bernardoni
2, M. C. Bove
1, L. Caponi
1, G. Valli
2, R. Vecchi
2, P. Prati
11: Dept. of Physics, University of Genoa & INFN Via Dodecaneso 33, 16146, Genova, Italy 2: Dept. of Physics, Università degli Studi di Milano & INFN Via Celoria 16, 20133, Milano, Italy
Motorized stage: l selection 16 positions filter wheel Photodiodes Stepper motors: filter selection and scanning 5 LASER diodes: 375nm 407nm 532 nm 635nm 850 nm
D. Massabò et al., JAS:60:34-46, 2013
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 07/11/2014 16/11/2014 25/11/2014 04/12/2014 13/12/2014 22/12/2014 31/12/2014 A A E babs [ Mm -1 ] @6 35 nm Date
b_abs BCff b_abs BCwb b_absBrC AAE
y = 2.39x + 0.05 R² = 0.96 0.0 0.2 0.4 0.6 0.8 1.0 0.00 0.10 0.20 0.30 0.40 B a bs BrC (Mm -1 ) @63 5n m Levoglucosan (mg m-3)
Absorption coefficient apportioned to BrC vs. Levoglucosan concentration BrC BC
b
a
b
b
b
b
abs
BrC
abs
BC
abs
abs
l
l
l
l
l
l
)
(
)
(
)
(
)
(
WB FFb
a
b
b
b
b
abs
WB
abs
FF
abs
abs
l
l
l
l
l
l
)
(
)
(
)
(
)
(
The “MWAA model
” [D. Massabò et al., 2015] exploits two different decompositions of b
abs,
based on:
1) The AAE of BrC (
BrC) <
BrC> = 3.8 0.2
Processing the absorption coefficients measured
at 5-l, the “MWAA model” provides:
2) The relative contributions to the total
absorption coefficient (b
abs) of
BC
FF,
BC
WBand
BrC
at every measured
l
SOURCES
BC and BrC spectral dependences
Samples: ≈ 300 24h PM10 samples, collected on quartz fiber filters.
The Multi-Wavelength Absorbance Analyzer
Instruments:
3) The apportionment of OC: from fossil fuels
(OC
FF), wood burning (OC
WB) and originated
by non combustion sources (OC
NC)
Where:
Sampling site: Propata, Ligurian
Appennines, ~ 1000 m a.s.l.
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 C o ncen tra ti o n [m g m -3 ] OCFF OCWB OCNCThe Multi-Wavelength Absorbance Analyzer (MWAA) is a prototype
instrument realized at the Physics Department of the University of Genoa.
We developed an algorithm for the apportionment of the absorption coefficient (b
abs
) of the atmospheric aerosols:
Mean BCFF, BCWB and BrC light absorption coefficients as a function of wavelength at Propata during winter 2014
y = 1.01 x + 0.15 R² = 0.98 0% 20% 40% 60% 80% 100% 120% 0% 20% 40% 60% 80% 100% f NF x 10 0 ( 14 C) ( TC - TCFF ) / TC
D. Massabò et al., Atmospheric Environment: 108, 1-12, 2015
y = 4.88x + 0.12 R² = 0.96 0.0 0.5 1.0 1.5 2.0 2.5 0.00 0.10 0.20 0.30 0.40 0.50 OC WB (m g m -3 ) Levoglucosan (mg m-3)
The methodology has been validated against Levoglucosan and
14C measurements:
The
split point
is operationally set at the moment in which the laser signal is back to its
starting value. EC/OC separation is based on the assumption that EC is the only light
absorbing species present on the filter.
This is no more true if BrC is present on the filter!
But we know the fraction absorbed by BrC @ 635nm (
MWAA model
)
14% 5% 4% 11% 12% 11% 5% 7% 0% 9% 7% 0% 14% 13% 15% 11% 3% 7% 8% 17% 11%14%23% 17% 22% 25% 10% 9% 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 EC (m g m -3 )
