Gas–Particle Distribution of PAHs in Wood Combustion Emission Determined with Annular Denuders, Filter, and Polyurethane Foam Adsorbent

Figures & data

FIG. 1 Schematics of the emission measurement system.

TABLE 1 Average temperatures and dilution ratios in normal combustion (NC) and smoldering combustion (SC) tests

	NC1	NC2	NC3	SC1	SC2	SC3
T(exhaust gas) [°C]	250	257	254	187	127	159
T(diluted sample) [°C]	24	25	25	24	25	24
DR	82:1	119:1	85:1	86:1	69:1	176:1

TABLE 2 The detection and quantitation limits for GC–MS

Compound (Abbreviation)	DL [ng]	QL [ng]
Acenaphthylene (Acy)	0.34	1.15
Acenaphthene (Ace)	0.21	0.70
Fluorene (Fle)	0.05	0.17
Phenanthrene (Phe)	0.04	0.13
Anthracene (Ant)	0.03	0.11
Fluoranthene (Fla)	0.39	1.29
Pyrene (Pyr)	0.23	0.76
Benz[a]anthracene (BaA)	0.14	0.47
Chrysene (Chr)	0.24	0.81
Benzo[b]fluoranthene (BbF)	3.04	10.14
Benzo[k]fluoranthene (BkF)	2.80	9.34
Benzo[a]pyrene (BaP)	0.46	1.52
Indeno[1,2,3-cd]pyrene (I123-cdP)	1.38	4.60
Dibenz[ah]anthracene (DahA)	2.15	7.16
Benzo[ghi]perylene (BghiP)	3.96	13.19

TABLE 3 The proportion of the gas phase emission collected on the first denuder in the three repeats of normal combustion (NC) and smoldering combustion (SC) tests [%]. The results which were rejected due to break through are marked with *. If a cell is blank, the analysis result has been below the detection limit

Compound	NC 1	NC 2	NC 3	SC 1	SC 2	SC 3
Acy	99	99	99	100	100	100
Ace	97	99	96	100	100	100
Fle	98	99	99	100	99	99
Phe	98	98	100	99	94	97
Ant	98	97	100	98	91	95
Fla	90*	87	99	76	75	75
Pyr	84*	85	97	75	73	73
BaA	73	69	72*	72	65	28
Chr	70	64	74*	63	73	25
BbF	100		100	87	100	0
BkF	69	58	63*	60	54	19
BaP	73	62	84	72	60	19
I123–cdP	100	57	85	97	67	34
DahA	63*	35*	100	100	42	67
BghiP			100	100	64	16

FIG. 2 Particle number distributions in diluted exhaust gas of normal combustion (NC) and smoldering combustion (SC) before and after the denuders, and size-segregated penetration of particles through the denuders. As distributions before the denuders, the actual particle number distributions measured from the diluted exhaust gas with the FMPS were used; the distributions after denuders have been modelled.

TABLE 4 The emission factors of 15 PAHs in the gas phase and in the particle phase at 24–25°C [mg/kg]

	Normal combustion						Smoldering combustion
	Gas phase			Particle phase			Gas phase			Particle phase
	Average	Min	Max	Average	Min	Max	Average	Min	Max	Average	Min	Max
Acy	23.46	5.11	36.06	— ^b	— ^b	— ^b	339.70	299.46	407.28	1.05 ^a	0.25	1.86
Ace	0.52	0.22	0.89	— ^b	— ^b	— ^b	17.07	13.62	18.99	— ^b	— ^b	— ^b
Fle	4.24	2.09	7.38	— ^b	— ^b	— ^b	63.13	55.73	74.12	— ^b	— ^b	— ^b
Phe	20.49	14.08	26.34	0.18 ^a	0.11	0.25	154.31	135.32	167.77	17.68	3.44	29.27
Ant	6.60	4.02	8.41	0.05 ^a	0.03	0.08	42.84	40.29	45.53	5.39	0.85	7.94
Fla	10.92 ^a	8.40	13.43	1.71 ^a	0.14	3.27	34.03	29.10	39.87	41.07	24.97	61.65
Pyr	11.16 ^a	8.47	13.86	2.45 ^a	0.22	4.68	31.85	26.84	37.35	46.41	29.69	67.93
BaA	0.53 ^a	0.27	0.78	1.71 ^a	0.85	2.58	1.27	1.10	1.51	13.88	11.02	19.24
Chr	0.71 ^a	0.38	1.05	2.01 ^a	0.98	3.05	1.50	0.93	2.24	14.02	10.56	18.96
BbF	0.17	ND	0.47	1.35	0.83	1.92	0.10	<QL	0.20	11.14	10.16	12.69
BkF	0.19 ^a	0.10	0.27	1.75 ^a	0.62	2.87	0.58^a	0.57	0.59	10.72	6.99	14.65
BaP	0.22	0.09	0.42	1.81	0.53	3.54	0.78	0.52	1.20	17.41	11.06	27.22
I123-cdP	0.04	0.01	0.09	1.41	0.20	2.34	0.40	0.37	0.45	17.83	8.30	30.97
DahA	— ^b	— ^b	— ^b	— ^b	— ^b	— ^b	0.05^a	0.05	0.06	1.19	0.54	2.32
BghiP	0.02	ND	0.05	1.10	0.09	2.28	0.48	0.30	0.81	10.69	5.32	19.01

FIG. 3 The PAH emissions from normal combustion sampled with denuder method and ISO 11338 method. The standard deviation is represented in the error bar (n = 3).

FIG. 4 The average gas particle distribution of PAHs determined with the denuder method in NC and SC and with ISO 11338 in NC. The standard deviation (error bar) is represented if n = 3; if not enough accurate data was available the minimum fraction in the gas phase has been estimated on the basis of the contaminated samples.

FIG. 5 Vapor pressures of PAHs in diluted exhaust gas in the temperature of 25°C in normal combustion (NC) and smoldering combustion (SC).

FIG. 6 Partitioning coefficient values K_p in diluted exhaust gas at 25°C in two smoldering combustion (SC) tests (PM₁ concentration in diluted exhaust gas in SC2 20.1 mg/m³ and in SC3 2.1 mg/m³, dilution ratios 69:1 and 176:1).

FIG. 7 Vapor pressures of PAHs in raw exhaust gas in the temperature of 250°C in normal combustion (NC).

FIG. 8 Gas phase concentration and total concentration of example compounds of three groups of PAHs in the NC and in the SC conditions (bars) and the saturation vapor pressures of Acy, Ace, Fle … at 25°C (stars).

TABLE 5 Physical properties of grouped PAHs (Lide, 2005)

Group	Compounds	Mole mass [g/mol]	Melting point [°C]	Boiling point [°C]
1	Acy, Ace, Fle, Phe, Ant	152…178	92…216	279…340
2	Fla, Pyr, BaA, Chr, BbF, BkF, BaP	202…252	110…256	384…480
3	I123-cdP, DahA, BghiP	276…278	162…273	No data available

Lide , D. R. , ed. 2005 . CRC Handbook of Chemistry and Physics , 3-4 – 3-448 . London : Taylor & Francis Group .

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