A EUROPEAN AEROSOL PHENOMENOLOGY: TOTAL CARBON, ELEMENTAL CARBON AND ABSORPTION COEFFICIENT Fabrizia Cavalli 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 The ACTRIS COMMUNITY

T OTAL C ARBON, E LEMENTAL C ARBON, PM MASS, ABSORPTION COEFFICIENT AND THEIR RATIOS, in PM2.5 and in PM10 10 EUROPEAN REGIONAL BACKGROUND SUPER-SITES 4 YEARS of data: 2008 – 2011 (different data coverage across the network) FINOKALIA BIRKENES VAVIHILL ASPVRETEN HARWELL MELPITZ KOSETICE PUY de DÔME ISPRA MONTSENY NORDIC CONTINENTAL HIGH ALTITUDE MEDITERRANEAN CONTENT of the STUDY:

COMMON STANDARDISED METHODOLOGY plus COMPARABILITY INFORMATION on: SAMPLING of CARBONACEOUS AEROSOLS on filters MEASUREMENT of: T OTAL C ARBON and E LEMENTAL C ARBON CONCENTRATION A BSORPTION COEFFICIENT RESEARCH&DEVELOPMENT and INTEGRATION ACTIVITIES for ATMOSPHERIC MEASUREMENTS within EUSAAR and ACTRIS EU-I NTEGRATED I NFRASTRUCTURES I NITIATIVES (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 1 TDQ Sampler 2 TQ Sampler 3 Q Teflon filters Quartz fiber filters Front quartz filter Denuder Sampling Head Carbon honeycomb monoliths 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 (C AVALLI et al., AMT 2010) for thermal-optical analysis 1.2- DATA HARMONISATION: ANALYSIS OF T OTAL, O RGANIC and E LEMENTAL C ARBON 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

1.3- 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 - laboratory systematic BIASES and HARMONISATION FACTORS: HF MAAP = 1 HF PSAP = HF AE = 1.6 see Poster: Absorbing properties of BC over Europe, M. Zanatta

HARMONISED ANNUAL AVERAGE of PM MASS, T OTAL C ARBON and E LEMENTAL C ARBON SIGNIFICANT POSITIVE GRADIENT from N to S 6 μgm -3 (BIR) - 30 μgm -3 (ISP) M ASS μg m -3 PM10 T OTAL C ARBON and E LEMENTAL C ARBON : 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 A BSORPTION COEFFICIENT 2.1 c RESULTS: A BSORPTION COEFFICIENT Mm -1 SIGNIFICANT POSITIVE GRADIENT from N to S: 0.8 Mm -1 (BIR) - 11 Mm -1 (ISP)

2.2a RESULTS: HARMONISED ANNUAL AVERAGE of T OTAL C ARBON / M ASS R ATIO L EAST CARBONACEOUS AEROSOL AT THE M EDITERRANEAN SITES, i.e. F INOKALIA and M ONTSENY : M OST CARBONACEOUS AEROSOL IN I SPRA : F OR THE MAJORITY OF THE SITES, FAIRLY HOMOGENEOUS T OTAL C ARBON / M ASS RATIO : T OTAL C ARBON / M ASS

2.2b RESULTS: HARMONISED ANNUAL AVERAGE of E LEMENTAL C ARBON / T OTAL C ARBON R ATIO F AIRLY HOMOGENEOUS (P UY DE D ÔME EXCEPTED ) E LEMENTAL C ARBON / T OTAL C ARBON RATIO : E LEMENTAL C ARBON / T OTAL C ARBON RATIO DEPENDS ON THE PROXIMITY OF EMISSION SOURCES E LEMENTAL C ARBON / T OTAL C ARBON

2.2c RESULTS: HARMONISED ANNUAL AVERAGE of A BSORPTION COEFFICIENT / E LEMENTAL C ARBON, I. E. MASS ABSORPTION CROSS SECTION m 2 g -1 MAC m 2 g -1 H OMOGENEITY IN THE MAC VALUES : 6. 6 m 2 g -1 (VHL) 16.1 m 2 g -1 (PdD) ( P d D AND VHL HAVE A POORER DATA COVERAGE WITH LESS THAN 150 DATA POINTS ) E UROPEAN REGIONAL BACKGROUND MAC = 10.8 ± 3.00

HARMONISED SEASONAL AVERAGES of T OTAL C ARBON / M ASS R ATIO WINTER SPRING SUMMER FALL WINTER SPRING SUMMER FALL PM2.5PM10 T OTAL C ARBON / M ASS SEASON - SPECIFIC SOURCES OF CARBONACEOUS AEROSOL RESULT IN : M OST CARBONACEOUS AEROSOL IN WINTER - FALL DUE TO DOMESTIC HEATING ( MORE EVIDENT AT CENTRAL SITES ) B IOGENIC AEROSOL PEAKS IN SUMMER L EAST CARBONACEOUS AEROSOL IN SPRING AT ALL SITES BUT F INOKALIA I NVERSE CYCLE AT FINOKALIA DUE TO AGRICULTURAL WASTE BURNING AND FOREST FIRES IN SPRING AND SUMMER 2.3a RESULTS:

HARMONISED SEASONAL AVERAGES of E LEMENTAL C ARBON / T OTAL C ARBON R ATIO E LEMENTAL C ARBON / T OTAL C ARBON WINTER SPRING SUMMER FALL WINTER SPRING SUMMER FALL PM2.5 PM10 E LEMENTAL C ARBON / T OTAL C ARBON RATIO SEASONAL CYCLE : MAXIMUM IN FALL - WINTER ( TRAFFIC + DOMESTIC HEATING ) AND MINIMUM IN SUMMER ( TRAFFIC + BIOGENIC SOURCES ) R EMARKS : -L ESS PRONOUNCED CYCLE AT CONTINENTAL SITES DUE TO WEAKER BIOGENIC SOURCES - AT F INOKALIA : MAXIMA IN SPRING - SUMMER DUE TO FIRES - AT P UY DE D ÔME : CYCLE DETERMINED MAINLY BY THE BOUNDARY LAYER DYNAMIC 2.3b RESULTS:

HARMONISED SEASONAL AVERAGES of A BSORPTION COEFFICIENT / E LEMENTAL C ARBON, I. E. MASS ABSORPTION CROSS SECTION WINTER SPRING SUMMER FALL MAC m 2 g -1 M AC SEASONAL CYCLE : - MAXIMUM IN SUMMER AT THE MAJORITY OF SITES - I N CORRESPONDENCE TO THE MINIMUM OF THE EC / TC RATIO ( I. E. MAXIMUM ABUNDANCE OF ORGANIC CARBON ) - T HIS WOULD INDICATE AN AMPLIFICATION OF EC ABSORPTIVITY BY THE THICKER O RGANIC C ARBON COATING 2.3c RESULTS:

3. CONCLUSIONS M ETHODOLOGICAL -I MPORTANCE OF COMMON STANDARDISED PROCEDURES FROM SAMPLING TO DATA SUBMISSION -T HIS IS A MORE EFFICIENT AND ACCURATE APPROACH THAN APPLYING a-posteriori CORRECTION FACTORS -P ERIODICAL CHECKS OF COMPARABILITY H IGHLY INTEGRATED NETWORK AND A BIAS - FREE DATASET ALLOW UNDERSTANDING SOURCES AND TRANSFORMATION OF AEROSOLS P HENOMENOLOGICAL O N A E UROPEAN REGIONAL BACKGROUND SCALE : -C LEAR POSITIVE SPATIAL GRADIENT – FROM N TO S – FOR ALL EXTENSIVE AEROSOL PROPERTIES : PM MASS, T OTAL C ARBON & ELEMENTAL C ARBON AND ABSORPTION COEFFICIENT - HOMOGENEITY FOR ALL INTENSIVE AEROSOL PROPERTIES : T OTAL C ARBON / M ASS, E LEMENTAL C ARBON / T OTAL C ARBON AND MAC -S EASONALITY OF INTENSIVE AEROSOL PROPERTIES AND SOURCES : -T OTAL C ARBON / M ASS : M AXIMA IN FALL - WINTER ( DOMESTIC HEATING ) AND IN SUMMER ( BIOGENIC AEROSOL ) -E LEMENTAL C ARBON / T OTAL C ARBON : M AXIMUM IN FALL - WINTER AND MINIMUM IN SUMMER -A BSORPTION COEFFICIENT / E LEMENTAL C ARBON : M INIMUM IN FALL - WINTER AND M AXIMUM IN S UMMER