Consistency and Traceability of Black Carbon Measurements Made by Laser-Induced Incandescence, Thermal-Optical Transmittance, and Filter-Based Photo-Absorption Techniques

Figures & data

FIG. 1 Experimental setup for the measurement of the size distributions of organic aerosols with or without the heated inlet. Total numbers of particles were measured by a CPC after size selection by a DMA.

TABLE 1 Summary of the measurement techniques for BC mass concentration used in this study

Acronym	Detection method	Calibration	Mass
SP2	Incandescence	APM + ambient BC or fullerene soot	M SP2
RMM	Mass	APM	M ref
TOT	Conversion to CO2	CH4/He standard gas	M TOT
COSMOS	Light absorption	TOT or SP2 + ambient BC	M COSMOS
RMM: Refractory Mass Method; APM is calibrated with standard PSL particles.

TABLE 2 Summary of the variable symbols and acronyms used in this study

Terminology	Definition
M ref	Mass of refractory components in ambient aerosol extracted by a heated inlet (single particle)
m*ref	Mass of refractory components in ambient aerosol that incandesce and are extracted by a heated inlet (single particle)
m full	Mass of fullerene soot (single particle)
M SP2	Mass of ambient BC detected by SP2 (single particle)
M ref	Total mass concentration of refractory particles in the fine mode
M SP2	Total mass concentration of BC measured by SP2 in the fine mode
M TOT	Total mass concentration of BC measured by the TOT method in the fine mode
M COSMOS	Total mass concentration of BC measured by the COSMOS in the fine mode
D m	Mobility diameter of refractory aerosol
D me	Mass equivalent diameter of refractory aerosol
D BC	Mass equivalent diameter of BC
b abs	Absorption coefficient measured by COSMOS
C abs(D BC, λ)	Absorption cross section of an airborne BC particle with diameter D BC at wavelength λ
C emit(D BC, λ)	Emission cross section of an airborne BC particle with diameter D BC at wavelength λ
N	Complex refractive index of BC
σ*abs	Mass absorption cross section of an airborne BC particle (λ= 565 nm for this study)
σabs	Mass absorption cross section of a BC particle collected on a filter (λ= 565 nm for this study)
f fil	Correction factor of the magnitude of BC photo-absorption by multiple scattering in the filter medium
CMD	Count median diameter
MMD	Mass median diameter
APM	Aerosol particle mass analyzer
DMA	Differential mobility analyzer
SMPS	Scanning mobility particle sizer
CPC	Condensation particle counter
SP2	Single-particle soot photometer
LII	Laser-induced incandescence
COSMOS	Continuous soot monitoring system
TOT method	Thermal-optical transmittance method

TABLE 3 Ratios of the volumes of organic particles downstream of the heated (400°C) and unheated inlets (heated/unheated) for different mobility diameters

			100 nm		150 nm		200 nm
Classification	Compound	MW	300°C	400°C	300°C	400°C	300°C	400°C
Saccharides	levoglucosan	162	0.002	0.001	0.002	0.009	0.003	0.003
Saccharides	sucrose	342	0.027	0.003	0.097	0.004	0.061	0.005
Saccharides	glucose	180	0.002	0.002	0.002	0.001	0.002	0.002
Dicarboxylic acid	malonic acid	104	0.016	0.011	0.015	0.011	0.018	0.011
Dicarboxylic acid	succinic acid	118	0.007	0.004	0.008	0.004	0.010	0.005
Dicarboxylic acid	adipic acid	146	0.048	0.042	0.053	0.048	0.060	0.055
Dicarboxylic acid	pimelic acid	160	0.035	0.029	0.032	0.026	0.035	0.027
Dicarboxylic acid	azelaic acid	188	0.007	0.004	0.010	0.006	0.014	0.009
Aromatic acids	phthalic acid	166	0.015	0.011	0.017	0.012	0.008	0.010
Humic-like^a	SRHA II	NA	0.87	0.72	0.93	0.74	0.87	0.75
Humic-like^a	SRFA I	NA	0.72	0.43	0.74	0.44	0.75	0.48
Humic-like^a	SRFA II	NA	0.82	0.62	0.85	0.66	0.91	0.76
Humic-like^a	PPFA	NA	0.87	0.76	0.90	0.78	0.91	0.80
^aProduced by the International Humic Substances Society and desalted (H^+-saturated) by cation exchange.

FIG. 2 Changes in the number size distributions of organic aerosols with changes in the temperature of the inlet (300° and 400°C) for organic species.

FIG. 3 Experimental setup for the calibration of the SP2 using ambient BC and commercially available BC particles. The particles were mass selected by means of an APM.

FIG. 4 Relationship between the LII peak intensity measured by the SP2 and the BC masses of ambient BC and fullerene soot.

FIG. 5 Thermograms of the HULIS obtained in the laboratory.

TABLE 4 Summary of thermograms of organic species standards. The data for levoglucosan, pimelic acid, and azelaic acid were taken from Miyazaki et al. (2007)

	Percentage of integrated peak area
Compound	OC1	OC2	OC3	OC4	OC5
Levoglucosan	62.2	17.8	8.1	8.9	3.0
Pimelic acid	43.2	6.4	22.3	25.3	4.8
Azelaic acid	1.8	5.9	29.3	57.6	5.4
SRHA II	0.6	9.3	11.6	25.5	53.0
SRFA I	1.3	10.4	16.6	18.1	53.6
SRFA II	1.3	10.7	15.8	24.6	47.6
PPFA	0.3	9.9	10.1	17.1	62.6

FIG. 6 Experimental setup for the measurement of the absorption coefficient of organic aerosols by means of two COSMOS instruments. COSMOS I was mounted downstream of a heater, and COSMOS II was operated without a heater. Total numbers of particles were measured by a CPC after size selection by a DMA.

FIG. 7 Plots of equivalent mass concentrations of BC measured by COSMOS with an inlet heated to 300°C and 400°C and without a heated inlet versus the volume concentrations of organic species. The equivalent mass concentrations of BC were derived from the observed absorption coefficients by assuming a mass absorption cross section of 5.4 m² g^–1.

TABLE 5 Slopes of correlation plots of equivalent BC mass concentrations versus volume concentration measured by COSMOS I (heated inlet) and COSMOS II (without heated inlet)

	Slope (μg m^–3)/(10^–6 cm^3 m^–3)				Net increase in slope
Compound	Unheated	r^2	300°C	r^2	400°C	r^2	300°C	400°C
PSL	0.029	0.12	NA	0.021	0.26
levoglucosan	0.0002	0.03	0.0000	0.06	0.0000	0.00
sucrose	0.033	0.86	0.0000	0.001	0.0000	0.00
glucose	0.0095	0.68	0.0000	0.12	0.0000	0.00
malonic acid	0.0025	0.29	0.0000	0.003	NA	NA
succinic acid	0.0000	0.00	0.0000	0.05	NA	NA
adipic acid	0.015	0.10	0.0000	0.08	0.0000	0.00
pimelic acid	0.0000	0.00	0.0000	0.00	0.0000	0.00
azelaic acid	0.0000	0.00	0.0000	0.07	0.0000	0.00
phthalic acid	0.026	0.90	0.0000	0.00	0.0000	0.00
SRHA II	0.021	0.16	0.024	0.06	0.069	0.007	0.003	0.048
SRFA I	0.012	0.60	0.014	0.74	0.039	0.71	0.002	0.027
SRFA II	0.0092	0.001	0.014	0.32	0.073	0.78	0.005	0.064
PPFA	0.025	0.28	0.030	0.83	0.089	0.91	0.005	0.064

TABLE 6 R ₃₀₀ (OC5) and R ₄₀₀ (OC5) of HULIS

Compound	R 300 (OC5)	R 400 (OC5)
SRHA II	0.060	0.174
SRFA I	0.035	0.097
SRFA II	0.039	0.204
PPFA	0.064	0.190
Average	0.050	0.166

TABLE 7 PC/BC ratios at different locations in Asia

			Relative interference (%)
Locations	Season/Airmass	Average PC/BC	300°C	400°C
Tokyo	Winter	0.063 ± 0.053	0.4 ± 0.3	1.0 ± 0.8
	Summer	0.047 ± 0.057	0.3 ± 0.3	0.7 ± 0.9
Jeju Island, Korea	Spring
	Average	0.04 ± 0.03	0.2 ± 0.2	0.6 ± 0.5
	Chinese	0.03 ± 0.02	0.2 ± 0.1	0.5 ± 0.3
	Marine	0.08 ± 0.05	0.4 ± 0.3	1.3 ± 0.08
Rural Guangzhou, China	Summer	0.28 ± 0.35	1.4 ± 2.1	4.6 ± 5.3
Rural Beijing, China	Summer	0.23 ± 0.22	1.1 ± 1.3	3.8 ± 3.6
Suburban Bangkok,	Summer (rainy season)	0.08 ± 0.27	0.4 ± 0.2	1.3 ± 4.4
Thailand	April (intense BB)	0.24 ± 0.37	1.2 ± 2.2	3.9 ± 6.1

FIG. 8 Daily averaged number and mass size distributions of black carbon measured by SP2 in Tokyo in August and September 2009.

FIG. 9 Frequency distribution of the CMD and MMD of the lognormal size distributions fitted to 1-min averaged BC mass size distributions measured by SP2.

FIG. 10 Frequency distribution of the shell/core (D _p/D _BC) ratios of BC particles with different D _BC size ranges.

FIG. 11 Time series plots of BC mass concentrations measured by SP2 and COSMOS, their ratios, and MMD in Tokyo from September 10 to September 12, 2009. The mass concentration of BC was derived from the observed absorption coefficients by assuming a mass absorption cross section of 5.4 m² g^–1.

FIG. 12 Correlation plots of BC mass concentrations measured by SP2 and those measured by COSMOS in 2009 using 1-min average data (left panel) and 1-h average data (right panel). Mass concentration of BC by COSMOS was derived from the absorption coefficients by assuming a mass absorption cross section of 5.4 m² g^–1. The least squares fitted line is denoted as the solid line.

FIG. 13 M _COSMOS/M _SP2 ratio versus the MMD of BC. The solid black line is the least squares fitted line, and the red squares denote the mean M _COSMOS/M _SP2 ratios for 10-nm MMD bins.

Miyazaki , Y. , Kondo , Y. , Han , S. , Koike , M. , Kodama , D. , Komazaki , Y. , Tanimoto , H. and Matsueda , H. 2007 . Chemical Characteristics of Water-soluble Organic Carbon in the Asian Outflow . J. Geophys. Res. , 112 ( D22S30 ) doi:10.1029/2007JD009116

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