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Black carbon: Characterisation, measurement methods, and emission factors Jana Moldanová IVL, Swedish Environmental Research Institute.

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Presentation on theme: "Black carbon: Characterisation, measurement methods, and emission factors Jana Moldanová IVL, Swedish Environmental Research Institute."— Presentation transcript:

1 Black carbon: Characterisation, measurement methods, and emission factors Jana Moldanová IVL, Swedish Environmental Research Institute

2 Black carbon Jana Moldanová, Definitions  Optical properties: Black carbon –Is formed by incomplete combustion of hydrocarbon fuels, and is the most effective component of PM, by mass, at absorbing solar energy –Mass of combustion-generated, sp2-bonded carbon that absorbs the same amount of light as the emitted particles. Absorption efficiency of the reference particles as 7 m 2 /g for 550-nm incident radiation (Bond 2004)  Thermal stability: Elemental carbon  Structure: Soot  Composition: Carbonaceous aerosol (includes OC)

3 Black carbon Jana Moldanová, Definitions

4 Black carbon Jana Moldanová, BC has a strong climate effect Aamas et al., 2013

5 Black carbon Jana Moldanová, BC sources - Europe 2. – non-industrial combustion 4. – production processes 9. – waste treatment and disposal 10 – agriculture van den Ggon, 2012

6 Black carbon Jana Moldanová, BC sources - Global Hendricks et al., 2013 BB for biomass burning, AWB for agricultural waste burning, AIRC for aviation, ANTH for other anthropogenic sources, VOLC for volcanoes and BIOG for biogenic sources.

7 Black carbon Jana Moldanová, Spatial distribution of BC in fine PM TRANSPHORM, van den Ghon, 2012

8 Black carbon Jana Moldanová, Uncertainties in source strength Kindbom in Hansson et al, 2012

9 Black carbon Jana Moldanová, BC mixing – uncertainties in light absorption

10 Black carbon Jana Moldanová, Measurement methods  Optical (BC) –in situ (Aethalometer) –filter analyses (Reflectande, trasmitance, Aethalometer, MAAP)  Thermal (EC/OC) –NIOSH, Improve, EUCAARI, VDI  Photo-acoustic (measures heat generated by absorbed radiation)

11 Black carbon Jana Moldanová, Optical Methods  Sampling on filter matrix  Measurement of modification of filter optical properties by the sampled PM  Assumption of Beer-Lambert law for data analyses  Response depends on filter loading and interaction between radiation, particles, and filter - requires corrections

12 Black carbon Jana Moldanová,  Multi-angle absorption photometer – both reflection and transmission – 2-stream model applied to evaluate results, no corrections Optical Methods

13 Black carbon Jana Moldanová, Thermal methods  Simple optical methods (oxidizing atmosphere, rizing T)  Two-step methods (thermal pre-treatment to remove OC)  Thermal-optical (optical correction for charring OC)  Thermal stability and the optical correction can be affected by presence of sulphate and metals in the PM

14 Black carbon Jana Moldanová, Thermal-optical method

15 Black carbon Jana Moldanová, Comparison of different optical and thermal methods (ship emissions) Different filter type for EC and BC

16 Black carbon Jana Moldanová, Comparison EC/BC – typically in range EPA, 2012

17 Black carbon Jana Moldanová, Emission estimates  From emission factors for EC/BC for individual sources –Traffic: HDV wo DPF mg/vkm, HDV w DPF 9-16 mg/vkm, PC w catalyst 1-2 mg/vkm PC petrol EURO mg/vkm PC diesel EURO mg/vkm –Residential wood burning – 3.5 g BC/kg wood (Kuipiainen & Klimont, 2007) Samaras, 2012

18 Black carbon Jana Moldanová, Emission estimates  From PM inventory and BC/PM ratio of the individual sources

19 Black carbon Jana Moldanová, Emission estimates  From PM inventory and BC/PM ratio of the individual sources TRANSPHORM, van den Ghon, 2012

20 Black carbon Jana Moldanová, Emission factors for BC – effect of sampling Figure 5 Composition of PM (as mg/m 3 exhaust gas) collected on filters in the diluted and hot exhaust gas (Moldanová et al., 2009).

21 Black carbon Jana Moldanová,  Dist. Fuel  PM composition profiles – ship emissions

22 Black carbon Jana Moldanová, PM composition profiles – ship emissions Volatility measured with online instruments (EEPS, GRIMM spectrometer, Thermodenuder) Part of PM mass and PM number volatilized at 90ºC (Vol. 90), 150ºC (Vol. 150) and 300ºC (Vol. 300) in the thermodenuder and the non-volatile part (Nonvol.).

23 Black carbon Jana Moldanová, PM composition – structure and composition of particles STEM image of an agglomerate of soot-type particles from HFO combustion. Composition: C 77.1 wt%, N 15.7 wt% and O 6.9 wt% and traces of V, Ca and S (about 0.1 wt% of each element). b – Elemental composition map of V, Ca and S for the soot-type particles in a. c – Elemental composition of different particles with respect to N, V, and S. a) b) c)

24 Black carbon Jana Moldanová, PM composition – structure and composition of particles STEM image of an agglomerate of soot-type particles from MGO combustion. b – Elemental composition map of S and Ca for the soot-type particles in a

25 Black carbon Jana Moldanová, a - TEM picture of a small soot-type aggregate and its corresponding selected area electron diffraction (SAED) pattern, b - zoom on soot-type particles with dark dots and its associated SAED pattern PM composition – structure and composition of particles

26 Black carbon Jana Moldanová, Oxidation behaviour of PM (TSP in black and PM 2.5 in red) sampled in a – HFO exhaust, b – MGO exhaust. PM composition affects thermal stability

27 Black carbon Jana Moldanová, Conclusions  Definition of BC is dependent of measurement technique used but also of impacts that are assumed (political definition)  Both optical and thermal methods give satisfactory results, impacts of PM composition on thermal methos need further consideration, further intercomparison of optical methods  Emission factors for BC and their variability with fuels, combustion conditions, technologies e.t.c. needs to be further developed  Consistency between PM and BC data important  PM composition affect both measurement results and how the particles behave in atmosphere (radiative properties, sink processes, health effects (?)  Relation between BC/EC emission at source and properties of these particles on mesoscale


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