1/30 2-year observation of organic aerosol properties in cape corsica j. sciare, and co-workers @...
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1/30
http://charmex.lsce.ipsl.fr
2-year observation of Organic Aerosol
propertiesIn Cape Corsica
J. Sciare, and co-workers @ LSCE
2/30
http://charmex.lsce.ipsl.fr Cape Corsica monitoring activitiesAerosol Chemistry by ACSM
2012 2013 2014
ACTRIS-ACSMIntercomparisonexercise at LSCE
ACSMIntercomparisonexercise at LSCE
Instrument & Stationsfailures
+ 535 days (24h) of valid ACSM data
+ A unique dataset to investigate sources (primary/secondary) and geographic origin of OA in W. Mediterranean
+ A component of the ACTRIS-ACSM network (QA/QC controlled datasets)
12
10
8
6
4
2
0
conc
entr
atio
ns, µ
g/m
3
01/07/2012 01/01/2013 01/07/2013 01/01/2014 01/07/2014date
Organic Nitrate Sulfate Ammonium Chloride
y = 0.90xR² = 0.82
0
5
10
15
20
0 5 10 15 20PM
1 (S
MPS
), µg
/m3
PM1 (ACSM), µg/m3
Comparison with SMPS data(2012-2014)
3/30
http://charmex.lsce.ipsl.fr Cape Corsica monitoring activitiesAerosol Chemistry by ACSM
0
1
2
3
4 Org
0.0
0.2
0.4
0.6 NO3
0
1
2
Janu
ary
Febr
uary
Mar
chAp
rilM
ayJu
ne July
Augu
stSe
ptem
ber
Octo
ber
Nove
mbe
rDe
cem
ber
SO4
Co
nce
ntr
atio
nµ
g/m
3
Co
nce
ntr
atio
nµ
g/m
3C
on
cen
trat
ion
µg
/m3
Maximum of OA and SO4 during summertime (max of OA in winter in continental
France)
2.03
0.30
0.99
0.50
0.26
POM
NO3
nss-SO4
NH4
EC
PMchem= 4.1 µg/m3
Contribution des composantes -PM1
PMchem= 6.1 µg/m3
Most the difference between PM1 and PM2.5 relies on
primary natural sources (sea salt and dust)
4/30
http://charmex.lsce.ipsl.fr Seasonal variability of the oxidation state of Organic Aerosols (OA) in Corsica
Temporal variability of specific organic fragments (f44, f43) related to Acid (CO2
+) and non-acid (C2H3O+ & C3H7+)
OOA
0.150.250.350.450.550.650.750.85
juin
juill
etao
ûtse
ptem
bre
octo
bre
nove
mbr
edé
cem
bre
janv
ier
févr
ier
mar
sav
rilm
ai
Kroll et al., Carbon oxidation state (OSc) as a metric for describingthe chemistry of atmospheric organic aerosol, Nature, 2011
OS
c
OSc= oxidation State of OA
1. Highly oxidized OA for 6 months of the year (from April to
August)
2. Less oxidized OA for 3 months of the year (from November to
January)
12
10
8
6
4
2
0
conc
entr
atio
ns, µ
g/m
3
01/07/2012 01/01/2013 01/07/2013 01/01/2014 01/07/2014date
Organic Nitrate Sulfate Ammonium Chloride
2-year ACSM observations
5/30
http://charmex.lsce.ipsl.fr
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.00 0.05 0.10 0.15 0.20
LV -OOA
Triangle plot from Ng et al. (ACP, 2010)
f43 (non-acid fragment in OOA)
f44
(A
cid
fra
gm
en
t in
OO
A)
Min OSc = November
Max OSc = August
Seasonal variability of the oxidation state of Organic Aerosols (OA) in Corsica
SV-OOA
LV –OOA : Low volatile (aged) oxidized OASV-OOA : Semi-volatile (fresh) oxidized OA
6/30
http://charmex.lsce.ipsl.fr
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1 2 3 4 5 6 7 8 9 10 11 12
Frac
tion
of H
OA
to th
e to
tal O
A, %
Frac
tion
of O
OA
to th
e to
tal O
A, %
Month of the Year
OOA
HOA
Seasonal variation of HOA and OOA(results from 15-month observations)
OOA 70% of OA during winter
months85% of OA during summer
months
20%
80%
HOA
OOA
On a yearly average
HOA = Hydrogen-Like Organic Aerosol primary –combustion- aerosols)
OOA = Oxygen-Like Organic Aerosol(secondary OA)
Seasonal variability of OA sources in Corsica
7/30
http://charmex.lsce.ipsl.fr
A factor 10 in the variability of OA concentrations BUT oxidation state of OA (f44, f43) remains very high and poorly variable (few percents)
Oxidation state of in Corsica:Focus on the Summer 2013 campaign
8
6
4
2
0
Load
ings
(ug/
m3)
UTC Time
NH4 Org SO4 NO3 Chl
0.15
0.20
0.25
0.30
0.35
f44
0.025
0.030
0.035
0.040
0.045
0.050
0.055
0.060
05/06 15/06 25/06 05/07 15/07 25/07 04/08
f43
ADRIMED
SAFMED
f44 (Acid OOA)
f43 (Non-Acid OOA)
Aerosol chemical composition in PM1
determined by the ACSM
8/30
http://charmex.lsce.ipsl.fr
POLTRACK V1.0.2 beta Quick Source mapperDate: 05/06-05/08/2013 / Hourly mean data / Hysplit – GDAS dataRestricting data to air masses lower than 1000m / Reject backtrajectories: less 2 per 0.1°x0.1° grid cellSmoothing Kernel-Gaussian function: 5
Scale Nb Occurrence 0 – 5
Occurrence of air masses
Scale [OM] = 0 - 5µg/m3
Organic Aerosol sources([OA])
Oxidation state of in Corsica:Focus on the Summer 2013 campaign
Scale OSc 0 – 1
Organic Aerosol oxidation state(OSc)
The largest emitting OA region influencing Cape Corsica during summer 2013 are continental originating from Italy and Central/Eastern Europe
The most oxidized OA are found for marine (highly processed) air masses (e.g. not fed by continental emissions)
9/30
http://charmex.lsce.ipsl.fr
0
100
200
300
400
500
600
700
0.21
0.22
0.23
0.24
0.25
Sola
r rad
iatio
n, W
/m²
f44
0
100
200
300
400
500
600
700
0.042
0.044
0.046
0.048
00:0
0
03:0
0
06:0
0
09:0
0
12:0
0
15:0
0
18:0
0
21:0
0
00:0
0
Sola
r rad
iatio
n, W
/m²
f43
f44 (Acid OOA)
f43 (Non-Acid OOA)
10:00 LT (morning)
21:00 LT (evening)
Photochemically-induced formation/destruction of non-acid OOA (f43)
Photochemically-induced formation of acid OOA (f44). Possibly with fragmentation
ACSM – Oxidation State of OA
10/30
http://charmex.lsce.ipsl.fr Conclusions
From the 2-year observation of PM1 chemical composition with ACSM at Cape Corsica …
Seasonal cycles of OA and SO4 (max in summer) in opposite phase compare to Northern France
Highly oxidized OA in Cape Corsica all over the year (70% during winter to up to 85% of OA in summer)
Seasonal cycle of the oxidation state of OA with minima in November and constant increase
Ambient chemical composition of PM1 a factor of 3 lower from compared to Northern France
During the SAFMED (summer 2013) campaign …
July 2013 characterized by the highest PM1, OA, and SO4 levels observed from mid-2012 till mid-2014 (apart from the pollution episod observed in March 2014)
Stable oxidation state of OA (independent of air masses origin) although [OA] have shown variability of a factor of 10
Diurnal variability in opposite phase for f44 and f43 (e.g. photochemically locally induced formation/destruction of non-acid OOA) concomittant with a decrease in the OM/OC ratio (seen by two different approaches)
Evidence of continental emissions of OA and higher oxidation state above the marine areas
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