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A EUROPEAN AEROSOL PHENOMENOLOGY:
TOTAL CARBON, ELEMENTAL CARBON
AND ABSORPTION COEFFICIENT
Fabrizia Cavalli and JP Putaud
European Commission – DG Joint Research Centre
M. Zanatta
Laboratory of Glaciology and Geophysics of Environment, St Martin d'Hères Cedex
Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, Villigen
• CARBONACEOUS AEROSOL, I.E. ELEMENTAL CARBON AND CO-EMITTED ORGANIC COMPOUNDS,
ARE RECEIVING INCREASING ATTENTION DUE TO EFFECTS ON HUMAN HEALTH AND ON GLOBAL
CLIMATE
• DIRECTIVE 2008/50/EC ON AMBIENT AIR QUALITY AND CLEANER AIR FOR EUROPE (21 MAY 2008)
CHAPTER II - SECTION 1 - Article 6 Assessment criteria
In addition to the assessments referred to in paragraphs 2, 3 and 4, measurements shall be made, at RURAL BACKGROUND LOCATIONS away from significant sources of air pollution, for the purposes of providing, as a minimum, information on the total mass concentration and the chemical speciation concentrations of fine particulate matter (PM2.5) on an annual average basis …
ANNEX IV MEASUREMENTS AT RURAL BACKGROUND LOCATIONS IRRESPECTIVE OF CONCENTRATION
Substances - Measurement of PM2.5 must include at least the total mass concentration and concentrations of appropriate compounds to characterise its chemical composition. At least the list of chemical species given below shall be included:
▪ Major inorganic ions: SO42–, Na+, NH4
+, Ca2+, NO3–, K+, Cl–, Mg2+
▪ ORGANIC CARBON (OC) AND ELEMENTAL CARBON (EC)
MOTIVATION:
CONCENTRATION
ABSORPTION COEFFICIENT
▪ TOTAL CARBON, ELEMENTAL CARBON, PM MASS, ABSORPTION COEFFICIENT in PM2.5 and in PM10
▪ 10 EUROPEAN REGIONAL BACKGROUND SUPER-SITES, part of the EMEP measurement NETWORK
▪ 4 YEARS of data: 2008 – 2011
FINOKALIA
BIRKENES
VAVIHILL
ASPVRETEN
HARWELL MELPITZ
KOSETICE
PUY de DÔMEISPRA
MONTSENY
NORDIC
CONTINENTAL
HIGH ALTITUDE
MEDITERRANEAN
CONTENT of the STUDY:
COMMON STANDARDISED METHODOLOGY plus COMPARABILITY INFORMATION on:
• SAMPLING of CARBONACEOUS AEROSOLS on filters (LEADED BY JRC)
• MEASUREMENT of:
TOTAL CARBON and ELEMENTAL CARBON CONCENTRATION (LEADED BY JRC)
ABSORPTION COEFFICIENT
RESEARCH&DEVELOPMENT and INTEGRATION ACTIVITIES for ATMOSPHERIC MEASUREMENTS
within EUSAAR and ACTRIS EU-INTEGRATED INFRASTRUCTURES INITIATIVES (2006 – on going)
UNIQUE STUDY:
HIGHLY HARMONISED DATASET AT ALL SITES
A- DEVELOPMENT of a STANDARD method and ADOPTION
EUSAAR - ARTIFACT-FREE SAMPLING TRAIN
Denuder efficiency from 40%-90% at different sites
1.1- DATA HARMONISATION: SAMPLING of CARBONACEOUS AEROSOLS
B- TESTS to assess SAMPLING ARTIFACT
across the network, in winter and summer
Sampler 1TDQ
Sampler 2TQ
Sampler 3Q
Teflon filters
Quartz fiber filters
Front filter
Denuder
Sampling Head
Carb
on
hon
eyco
mb
m
on
olit
hs
Back-up filters
- HARMONISATION CORRECTIONS for POSITIVE ARTIFACT:
• Maximum average correction -30% for TC
• no information for 3 sites
- NEGATIVE ARTIFACT NOT EXACERBATED BY DENUDER: <5%
A- DEVELOPMENT of a STANDARD method and ADOPTION
EUSAAR_2 protocol (CAVALLI et al., AMT 2010) for thermal-optical analysis
officially adopted as standard method by EMEP
1.2- DATA HARMONISATION: ANALYSIS OF TOTAL, ORGANIC and ELEMENTAL CARBON
B- EXERCISES to assess INTER-LABORATORY COMPARABILITY within the NETWORK
Five inter-laboratory comparisons
- laboratory systematic BIASES and HARMONISATION FACTORS:
• max average deviation for EC/TC of 20% among sites using EUSAAR_2
• TC and EC with protocols other than EUSAAR_2 at two sites: max average deviation on EC/TC of a factor 2.3
1 2a 2b 3 6 7 8 12 13 16 17 25 26
A10
A 1
8 E1 E2 E3
-4
-3
-2
-1
0
1
2
3
4
SPA-1 SPA-2HUN-1HUN-2ITA-1ITA-2
Laboratory
z-sc
ores
1.3- DATA HARMONISATION: MEASUREMENT of ABSORPTION COEFFICIENT
FILTER-BASED INSTRUMENTS :
• MAAP: MULTI ANGLE ABSORPTION PHOTOMETER (4)
• PSAP: PARTICLE SOOT ABSORPTION PHOTOMETER (2)
• AE: AETHALOMETER (2)
A- ADOPTION of STANDARDISED DATA CORRECTION PROCEDURES:
• MAAP: SHIFT OF THE OPERATIVE WAVELENGTH (MÜLLER et al., 2011)
• PSAP: CORRECTION FOR RESPONSE TO ABSORPTION AND SCATTERING (BOND et al., 1999; OGREN, 2010)
• AE: CORRECTION FOR MULTIPLE SCATTERING AND SHADOWING EFFECTS (WEINGARTNER et al., 2003)
- ADJUSTED OF ABSORPTION COEFFICIENT TO A COMMON WAVELENGTH 637 nm with constant Absorption Ångstrom Exponent of 1
B- WORKSHOPS to assess the INTER-INSTRUMENT COMPARABILITY within the NETWORK
- instrument systematic BIASES and HARMONISATION FACTORS:
HFMAAP= 1 HFPSAP= 0.96-1.03 HFAE= 1.6
BIR MSY MLP OBK ISP
0
2
4
6
8
10
12PM2.5
BIRASP
VHL
HW
LPdD
MSY
MLP IS
PFN
K
0
2
4
6
8
10
12PM10
BIR ASP VHL HWL MSY MLP ISP FNK
0
5
10
15
20
25
30PM10
HARMONISED ANNUAL AVERAGE of PM MASS, TOTAL CARBON and ELEMENTAL CARBON
SIGNIFICANT POSITIVE GRADIENT from N to S
6 μgm-3 (BIR) - 30 μgm-3 (ISP)
MA
SS
μg
m-3
EL
EM
EN
TA
L
CA
RB
ON
TO
TA
L C
AR
BO
N μ
g
m-3
BIR MSY MLP OBK ISP
0
10
20
30
40
50
60PM2.5
• PM10 TOTAL CARBON and ELEMENTAL CARBON:
SIGNIFICANT POSITIVE GRADIENT from N to S
TC: 1 μgm-3 (BIR) - 10 μgm-3 (ISP)
EC: 0.1 μgm-3 (BIR) - 2 μgm-3 (ISP)
2.1 a,b RESULTS:
PdD high altitude site – special case!
NORTHWEST SOUTH
• PM10 Mass:
HARMONISED ANNUAL AVERAGE of ABSORPTION COEFFICIENT
2.1 c RESULTS:
AB
SO
RP
TIO
N C
OEFFIC
IEN
TM
m-1
• SIGNIFICANT POSITIVE GRADIENT from N to S: 0.8 Mm-1 (BIR) - 11 Mm-1 (ISP)
BIR VHL HWL PdD MSY MLP ISP FKL
0
2
4
6
8
10
12PM10
2.2a RESULTS:
HARMONISED ANNUAL AVERAGE of TOTAL CARBON / MASS RATIO
LEAST CARBONACEOUS AEROSOL AT THE MEDITERRANEAN SITES, i.e. FINOKALIA and MONTSENY: 0.11 - 0.14
MOST CARBONACEOUS AEROSOL IN ISPRA: 0.30 - 0.40
FOR THE MAJORITY OF THE SITES, FAIRLY HOMOGENEOUS TOTAL CARBON / MASS RATIO: 0.16 - 0.24
BIR MSY MLP OBK ISP
0.0
0.1
0.2
0.3
0.4
0.5PM2.5
BIR ASP VHL HWL MSY MLP ISP FNK
0.0
0.1
0.2
0.3
0.4
0.5
0.6PM10
TO
TA
L C
AR
BO
N /
MA
SS
2.2b RESULTS:
HARMONISED ANNUAL AVERAGE of ELEMENTAL CARBON / TOTAL CARBON RATIO
FAIRLY HOMOGENEOUS (PUY DE DÔME EXCEPTED) ELEMENTAL CARBON / TOTAL CARBON RATIO: 0.12-0.23
ELEMENTAL CARBON / TOTAL CARBON RATIO AFFECTED BY THE PROXIMITY OF EMISSION SOURCES
BIR MSY MLP OBK ISP
0.00
0.05
0.10
0.15
0.20
0.25
0.30PM2.5
BIR ASP VHLHWLPdD MSYMLP ISP FNK
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35PM10
ELEM
EN
TA
L C
AR
BO
N
/ TO
TA
L C
AR
BO
N
2.2c RESULTS:
HARMONISED ANNUAL AVERAGE of ABSORPTION COEFFICIENT / ELEMENTAL CARBON,
I.E. MASS ABSORPTION CROSS SECTION m2 g-1
MA
C m
2 g
-1
BIR VHL HWL PdD MSY MLP ISP FKL0
2
4
6
8
10
12
14
16
18PM10
• HOMOGENEITY IN THE MAC VALUES: 6. 6 m2 g-1 (VHL) — 16.1 m2 g-1 (PdD)
(PdD AND VHL HAVE A POORER DATA COVERAGE WITH LESS THAN 150 DATA POINTS)
• “EUROPEAN REGIONAL BACKGROUND” MAC = 10.8 ± 3.00
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50BIR
ASP
VHL
HWL
MSY
MLP
ISP
FNK
HARMONISED SEASONAL AVERAGES of TOTAL CARBON / MASS RATIO
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
PM2.5 PM10
TO
TA
L C
AR
BO
N /
MA
SS
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
BIRMSYMLPISPOBK
2.3a RESULTS:
SEASON-SPECIFIC SOURCES OF CARBONACEOUS AEROSOL MODULATE
THE SEASONAL CYCLE OF TOTAL CARBON / MASS RATIO
• CARBONACEOUS AEROSOL CONTRIBUTION FROM TRAFFIC CONSTANT THROUGHOUT THE YEAR
• MOST CARBONACEOUS AEROSOL IN WINTER-FALL DUE TO WOOD BURNING
• BIOGENIC AEROSOL PEAKS IN SUMMER
• LEAST CARBONACEOUS AEROSOL IN SPRING
• INVERSE CYCLE AT FINOKALIA DUE TO AGRICULTURAL WASTE BURNING AND FOREST FIRES IN SPRING AND SUMMER
FALL
SU
MM
ER
WIN
TER
TRAFFIC
WOOD BURNING WOOD BURNINGBIOGENIC AEROSOL
SP
RIN
G
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50BIR
ASP
VHL
HWL
MSY
MLP
ISP
FNK
2.3a RESULTS: HARMONISED SEASONAL AVERAGES of TOTAL CARBON / MASS RATIO
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
PM2.5 PM10TO
TA
L C
AR
BO
N /
MA
SS
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
BIRMSYMLPISPOBK
TC
/ M
ASS
HARMONISED SEASONAL AVERAGES of ELEMENTAL CARBON / TOTAL CARBON RATIO
ELEM
EN
TA
L C
AR
BO
N /
TO
TA
L C
AR
BO
N
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
PM2.5 PM10
ELEMENTAL CARBON / TOTAL CARBON RATIO SEASONAL CYCLE: MAXIMUM IN FALL-WINTER AND MINIMUM IN SUMMER
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
BIRMSYMLPISPOBK
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30 BIRASPVHLHWLPdDMSYMLPISPFNK
2.3b RESULTS:
2.3b RESULTS: HARMONISED SEASONAL AVERAGES of ELEMENTAL CARBON / TOTAL CARBON RATIO
ELEM
EN
TA
L C
AR
BO
N /
TO
TA
L C
AR
BO
N
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
PM2.5 PM10
REMARKS:
- LESS PRONOUNCED CYCLE AT CONTINENTAL SITES DUE TO WEAKER BIOGENIC SOURCES/OR STRONGER TRAFFIC SOURCE
- AT FINOKALIA: MAXIMA IN SPRING-SUMMER DUE TO FIRES
- AT PUY DE DÔME: CYCLE DETERMINED MAINLY BY THE BOUNDARY LAYER DYNAMIC
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
BIRMSYMLPISPOBK
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30 BIRASPVHLHWLPdDMSYMLPISPFNK
FALLSU
MM
ER
WIN
TER
WOOD BURNING WOOD BURNING
BIOGENIC AEROSOL
SP
RIN
G
TRAFFIC
EC
/ T
C
HARMONISED SEASONAL AVERAGES of ABSORPTION COEFFICIENT / ELEMENTAL CARBON,
I.E. MASS ABSORPTION CROSS SECTION
WIN
TER
SP
RIN
G
SU
MM
ER
FALL
MA
C m
2 g
-1
MAC SEASONAL CYCLE:
- MAXIMUM IN SUMMER AT THE MAJORITY OF SITES
- IN CORRESPONDENCE TO THE MINIMUM OF THE EC/TC RATIO (I.E. MAXIMUM ABUNDANCE OF ORGANIC CARBON)
- THIS WOULD INDICATE AN AMPLIFICATION OF EC ABSORPTIVITY BY THE THICKER ORGANIC CARBON COATING
2.3c RESULTS:
0
2
4
6
8
10
12
14
16
18
20
BIR
HWL
PdD
MSY
MLP
ISP
FNK
3. CONCLUSIONS
PHENOMENOLOGICAL
HIGHLY INTEGRATED NETWORK AND A BIAS-FREE DATASET ALLOW
UNDERSTANDING SOURCES AND TRANSFORMATION OF AEROSOLS
ON A EUROPEAN REGIONAL BACKGROUND SCALE:
- CLEAR POSITIVE SPATIAL GRADIENT – FROM N TO S – FOR ALL EXTENSIVE AEROSOL PROPERTIES:
PM MASS, TOTAL CARBON & ELEMENTAL CARBON AND ABSORPTION COEFFICIENT
- HOMOGENEITY FOR ALL INTENSIVE AEROSOL PROPERTIES:
TOTAL CARBON / MASS, ELEMENTAL CARBON / TOTAL CARBON AND MAC - SEASONALITY OF INTENSIVE AEROSOL PROPERTIES AND SOURCES:
- TOTAL CARBON / MASS: MAXIMA IN FALL-WINTER (WOOD BURNING) AND IN SUMMER
(BIOGENIC AEROSOL)
- ELEMENTAL CARBON / TOTAL CARBON: MAXIMUM IN FALL-WINTER AND MINIMUM IN SUMMER
- ABSORPTION COEFFICIENT / ELEMENTAL CARBON: MINIMUM IN FALL-WINTER AND MAXIMUM
IN SUMMER
SCIENTIFIC PUBLICATION (CAVALLI ET AL., in preparation)
METHODOLOGICAL:
- IMPORTANCE OF COMMON STANDARDISED PROCEDURES FROM SAMPLING TO DATA
SUBMISSION
- THIS IS A MORE EFFICIENT AND ACCURATE APPROACH THAN APPLYING a-posteriori
CORRECTION FACTORS
- PERIODICAL CHECKS OF COMPARABILITY
INTERNATIONAL PROGRAMMES (EMEP AND AQUILA)
EUROPEAN TECHNICAL BODY FOR STANDARDS – CEN WG 35 – IN SUPPORT TO EU-DIR IMPLEMENTATION
INTERNATIONAL OBSERVATIONS-MODELS COMPARISON INITIATIVES - AEROCOM
JRC EXPERTISE
PROJECT PRODUCTS
PILOT EXPERIMENT