Source Apportionment of Carbonaceous Particulate Matter in a Shanghai Suburb Based on Carbon Isotope Composition

Figures & data

FIG. 1 The sampling site. (Color figure available online.)

TABLE 1 The averaged carbon isotope composition of atmospheric particles^a

	δ^13C (‰)		^14C (pMC (%))
Aerosol size (μm)	OC	EC^b	OC	EC^b
<0.49	−26.49 ± 0.96	−25.53 ± 0.56	31.0 ± 23.1	43.3 ± 4.7
0.49–0.95	−27.12 ± 0.52	−26.03 ± 0.56	63.0 ± 7.9	50.0 ± 7.9
0.95–1.5	−26.18 ± 0.11	−25.14 ± 0.75	62.3 ± 15.3	44.7 ± 2.3
1.5–3.0	−26.53 ± 0.58	−25.58 ± 1.82	66.3 ± 5.9	53.7 ± 6.7
3.0–7.2	−26.02 ± 0.11	−24.80 ± 0.26	69.3 ± 3.3	42.3 ± 0.6
>7.2	−27.21 ± 0.65	−25.11 ± 0.43	69.1 ± 5.9	49.3 ± 11.0
^aδ^13Csample=δ^13Cmeasured−(ϕblank×δ^13Cblank)/1−ϕblank, pMCsample=pMCmeasured−(ϕblank×pMCblank)/1−ϕblank, where ϕblank is the ratio of OC and EC from blank correction to the corresponding OC and EC derived from the samples. The OC and EC of combustion blanks were 0.12 ± 0.04 mg and 0.15 ± 0.05 mg, respectively. δ^13C and pMC of the combustion-derived OC blank were –19.97 ± 0.09‰ and 0.92 ± 0.04%, respectively, while the values of EC were –20.36 ± 0.11‰ and 0.90 ± 0.07%, respectively. The standard CO2 derived from coal was used to evaluate the contamination during the graphitization. The ages of three blank samples were 44,250, 44,128, and 42,670 years. So, the contamination during this process can be neglected.
^bThe EC contained δ^13C and pMC values from OP, which accounted for about 30% of the EC (Szidat et al. 2004b).When the pMC and δ^13C of OP are assumed to be the same as those of OC and subtracted, the pMC of EC will decrease by –12%, 11%, 17%, 10%, 27%, and 18%, and the δ^13C will increase by 1.6%, 1.8%, 1.8%, 1.6%, 3.1%, and 3.6% for the particles of size <0.49, 0.49–0.95, 0.95–1.5, 1.5–3.0, 3.0–7.2, and >7.2 μm.

TABLE 2 The carbon isotope composition of the reference materials

	δ^13C (‰)
	OC				EC			pMC (%) OC
Source profiles	Wood	Soil	Coal	Vehicle	Wood^a	Coal	Vehicle	Wood	Soil
<0.49	−29.18	−26.29			−26.56			113.0	48.1
0.49–0.95	−31.90	−26.71			−27.11			120.7	61.6
0.95–1.5	−27.39	−25.43			−25.05			114.9	54.3
1.5–3.0	−29.96	−24.71			−25.13			125.0	69.7
3.0–7.2	−23.56	−22.16			−26.54			123.5	71.4
>7.2	−23.71	−24.04			−25.04			134.6	67.5
Literature			−23.5^b	−28.44 (−27.9)^c		−23.5^b	−26.75 (−27.9)^d
Atmospheric CO2								105.1 ± 2.3
New leaves, grass								103.8 ± 1.1
Biogenic emissions	C3: −27; C4: −13^c
^aThe δ^13C of the wood burning EC included the OP fraction.
^bThe average δ^13C of Chinese coal (Tang 2001).
^cThe average δ^13C of the liquid fuels (Widory 2006).
^dThe standard values of δ^13C for C3 and C4 plants (Deines 1980).

TABLE 3 The carbon isotope composition of OC from the biomass source

	OC from biomass burning		OC from biogenic emissions		Biomass source
Size (μm)	Concentration (μg·m^–3)	Fraction (%)	Concentration (μg·m^–3)	Fraction (%)	pMC (%)	δ^13C (‰)
<0.49	1.52	38	2.47	62	107.3	−27.66
0.49–0.95	3.38	76	1.05	24	116.7	−30.67
0.95–1.5	1.19	64	0.66	36	110.9	−27.15
1.5–3.0	0.57	47	0.64	53	113.8	−28.25
>.0–7.2	1.12	42	1.57	58	112.0	−25.40
7.2	0.73	27	1.98	73	112.1	−25.91

FIG. 2. Size-fractional distributions of soil dust, biomass burning, biogenic emissions, coal burning, and vehicle exhaust to the OC of atmospheric particulate matter in Jiading, Shanghai. (Data are expressed as average value and standard deviation of the three sets samples). (Color figure available online.)

FIG. 3. Size-fractional distributions of biomass burning, coal burning, and vehicle exhaust to the EC of atmospheric particulate matter in Jiading, Shanghai. (Data are expressed as average value and standard deviation of the three sets samples.) (Color figure available online.)

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