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http://charmex.lsce.ipsl.fr

2-year observation of Organic Aerosol

propertiesIn Cape Corsica

J. Sciare, and co-workers @ LSCE

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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)

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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)

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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

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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

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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

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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)

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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