Jean-Philippe Putaud, Fabrizia Cavalli Investigations on measurement protocols for carbonaceous aerosols compounds at JRC-Ispra (IES) Jean-Philippe Putaud, Fabrizia Cavalli European Commission, Joint Research Centre, Institute for Environment and Sustainability EMEP TFMM 10 May. 06

Sampling artifacts -1 related to G/P equilibrium shifts OC collection depends on face velocity EC collection does not Pressure drop induced volatilization from collected POC OR Face velocity dependence of VOC adsorption 1990, Mc Dow and Huntzicker: Sampling artifacts -1 related to G/P equilibrium shifts EMEP TFMM 10 May. 06

Sampling artifacts -2 Negative artifacts can reach 80% 1993, Eatough et al.: Negative artifacts can reach 80% EMEP TFMM 10 May. 06

Sampling artifacts -3 Positive artifacts account for > 25% 1993, Turpin et al.: Positive artifacts account for > 25% EMEP TFMM 10 May. 06

obtained with cascade impactors vs filter samplers Total Carbon in PM2.5 obtained with cascade impactors vs filter samplers Sampling artifacts -4 2004, Ten Brink et al.: Consistently lower concentrations of total carbon with cascade-impactors vs. fiber filter samplers EMEP TFMM 10 May. 06

Denuder (1): Teflon a. Eliminate positive artifacts denuder quartz EMEP TFMM 10 May. 06

The C honey comb monolith denuder (R&P) 4 to 8 cm high, 4 cm diameter carbon monolith multi-channel structure residence time = 0.15 to 0.3 s at 20 LPM efficiency = being tested EMEP TFMM 10 May. 06

that otherwise would adsorb on the quartz front filter Denuder (3): MARCH 2006 Denuder efficiency: on average, the C honey comb monolith denuder retains 60 - 85% of the VOCs (+ SVOCs) that otherwise would adsorb on the quartz front filter EMEP TFMM 10 May. 06

Denuder (4): …for a selected sample 200°C 300°C 450°C 650°C 650°C EMEP TFMM 10 May. 06

Denuder (5): < 20% ≈50% Positive artefacts relevance Positive artifact contribution is larger (up to ca. 50%) when particulate TC (PM2.5) concentrations are lower. EMEP TFMM 10 May. 06

a. Eliminate positive artifacts denuder Sorbent (1): a. Eliminate positive artifacts denuder b. Determine negative artifacts sorbent EMEP TFMM 10 May. 06

Sorbent (2): Pre-fired quartz fiber filters (QFF) SEPTEMBER 2005 No significant differences between back-up_1 and back-up_2 QFF efficiency recently tested: POOR EMEP TFMM 10 May. 06

Sorbent (3): C-impregnated glass fiber filter (CIG) Teflon CIG_1 Sorbent (3): C-impregnated glass fiber filter (CIG) EMEP TFMM 10 May. 06

The issue of blank levels is very critical Sorbents (4): Not only efficiency in trapping what is lost from the quartz filters is to be considered: The issue of blank levels is very critical Efficiency of denuder with respect to CIG filters EMEP TFMM 10 May. 06

Sorbents (4): a. Eliminate positive artifacts denuder b. Determine negative artifacts sorbent c. Negative artifact evaluation suitable denuder EMEP TFMM 10 May. 06

Denuder vs CIG filter (1): MARCH 2006 Denuder efficiency / CIG filters: on average, the C honey comb monolith denuder retains 50 - 80% of the VOCs (+ SVOCs) that otherwise would adsorb on CIG filters EMEP TFMM 10 May. 06

Denuder vs CIG filter (2): …for a selected sample Pk1 @ 200C Pk2 @ 300C 200C 300C EMEP TFMM 10 May. 06

Analytical procedure (1): Carbonaceous particle conference round robin stage 2, unpublished EC /TC EMEP TFMM 10 May. 06

Analytical procedure (2): Charring to be avoided or corrected OC / EC split EMEP TFMM 10 May. 06

Analytical procedure (3): properly calibrate the instrument detect pure organics (and mixtures) as OC and pure EC as EC EMEP TFMM 10 May. 06

Analytical procedure (4): Pk1 μgC cm-2 Pk2 Pk3 Pk4 Pyrol EC1 EC2 OC EC TC 0.01 0.26 2.49 1.06 7.41 6.97 0.41 11.23 0.00 EMEP TFMM 10 May. 06

Analytical procedure (4): Thermal Creation of EC-Only Test Samples form Atmospheric Aerosols Carrier gas Temperature (C) Time (s) He 50 Purging online He_1 600 60 He_2 800 300 Charring Minimization in Thermal Analysis of Aerosol Carbon J. Z. Yu and Q. Li EC/OC workshop, Durango, CO March 2003 EMEP TFMM 10 May. 06

Analytical procedure (4): TC μgC cm-2 TC_in He μgC cm-2 %TC_He @ 650 C 8.78  0.74 0.22  0.21 2.5 @ 750 C 3.90  0.49 0.63  0.23 16 @ 850 C 5.86  0.59 1.24  0.26 21 EMEP TFMM 10 May. 06

Analytical procedure (5): properly calibrate the instrument detect pure organics (and mixtures) as OC and pure EC as EC avoid or reduce the occurrence of charring during analysis keep the amount of carbon as small as possible volatilise as much as possible at low T avoid peak overlap correct for charring EMEP TFMM 10 May. 06

Analytical procedure (6): Seek agreement between optical and thermal methods ? Neuhaeusel, France-Germany border, 2003 EMEP TFMM 10 May. 06

Solutions are being tested (seasonal dependent) Conclusions: Sampling train: Solutions are being tested (seasonal dependent) Positive preliminary results To be tested in various environments (EUSAAR) Analytical procedures Strong arguments can be used to discriminate unacceptable methods Consensus still to be found on a “standardised” method EMEP TFMM 10 May. 06

Thanks EMEP TFMM 10 May. 06

Analytical procedure (5): EMEP TFMM 10 May. 06