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