Characterization of Organic Particles from Incense Burning Using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer

Figures & data

TABLE 1 Signal contribution (%) and possible ion formula in unit-mass-resolution (UMR) mass spectra of organic particles from the burning of IS, IC, and MC

m/z ^1	IS	IC	MC	Ion formula^2
27	3.3	4.1	3.8	CHN^+, C2H3 ^+
29	7.0	8.1	8.0	CHO^+, C3H5 ^+
41	3.5	3.3	3.8	C2HO^+, C3H5 ^+
43	5.6	6.9	7.7	C2H3O^+, C3H7 ^+
55	3.2	2.9	3.8	C3H3O^+, C4H7 ^+
57	2.3	2.6	3.5	C3H5O^+, C4H9 ^+
60	1.3	1.6	2.8	C2H4O2 ^+
73	1.1	1.3	1.7	C3H5O2 ^+
77	1.2	0.9	0.8	C6H5 ^+
81	1.3	0.9	1.0	C5H5O^+, C6H9 ^+
91	1.2	0.7	0.6	C7H7 ^+
107	0.7	0.4	0.4	C7H7O^+, C8H11 ^+
121	0.4	0.3	0.8	C7H5O2 ^+, C8H9O^+
137	2.6	0.7	0.7	C8H9O2 ^+, C10H17 ^+
151	0.4	0.3	0.2	C8H7O3 ^+, C9H11O2 ^+
167	1.5	0.5	0.3	C9H11O3 ^+
181	0.2	0.2	0.2	C9H9O4 ^+, C10H13O3 ^+
100–300	24.9	15.8	15.1
100–200	22.6	13.9	13.3
Note: IS, incense sticks; IC: incense coils; MC: mosquito coils.
^1Ions of different m/z values are grouped into three categories. Group I, homologous ions; Group II, sugar anhydrides and aromatics-related ions; Group III, lignin-related ions. The ion CHN^+ is listed here due to its relatively high intensity (Figure S6), but it does not belong to the three groups above.
^2Formulas of ions that have high intensities; not meant to be comprehensive.

FIG. 1 Average unit-mass-resolution (UMR) mass spectra of organic compounds in particles from burning three types of incense: incense stick (IS), incense coil (IC), and mosquito coil (MC). Three groups of ions, including homologous series (Group I), sugar- and aromatics-related ions (Group II), and lignin-related ions (Group III), are chosen for further analysis.

FIG. 2 High-resolution (HR) mass spectra of lignin-related ions (Group III) from burning three types of incense. A peak in the region of m/z 107 (before C₇H₇O⁺), more obviously shown in panels (b) IC and (c) MC, should be C₆H₃O₂ ⁺. It is not included in the fitting here since its peak is much smaller than the others (C₇H₇O⁺ and C₈H⁺ ₁₁). At m/z 167, the ion C₈H₇O₄ ⁺ can be due to phthalates (McLafferty and Turecek 1993) but the other ion (C₉H₁₁O₃ ⁺) is due to organics from incense burning and it dominates. (Color figure available online.)

FIG. 3 Example of correlations: the mass spectrum from mosquito coil (MC) with mass spectra from (a) levoglucosan, (b) lignin powder, and (c) PMF-resolved BBOA. Pearson's r values and slopes in the correlations of mass spectra from different BBOA, including particles from incense burning, with those of (d) levoglucosan, (e) lignin powder, and (f) PMF-resolved BBOA.

FIG. 4 Proposed fragments from lignin monomeric units. (Color figure available online.)

FIG. 5 High-resolution mass spectra of particulate organics from burning (a) incense stick (IS), (b) incense coil (IC), and (c) mosquito coil (MC), using the modified fragmentation table (frag_18/28_v_i). The inserted pie charts on the left represent the percentages of hydrocarbon ions (C_xH_y), oxygenated ions (C_xH_yO_z), and others (N- and S-containing compounds). See Section 3.3 for description of these three categories. The pie charts on the right represent the percentages of ions with molecular formula of C _n H_2n+1 (saturated) and C _n H_<2n+1 (unsaturated or cyclic). (Color figure available online.)

TABLE 2 Oxygen to carbon elemental ratio (O/C), hydrogen to carbon elemental ratio (H/C), and organic matter to organic carbon (OM/OC) ratio of organic compounds in particles from the burning of IS, IC, and MC

	O/C	H/C	OM/OC
IS_v2	0.29	1.51	1.54
IC_v2	0.33	1.52	1.60
MC_v2	0.32	1.58	1.59
IS_v_i	0.52	1.70	1.86
IC_v_i	0.52	1.55	1.86
MC_v_i	0.42	1.61	1.72
Aiken et al.^a	0.3–0.4	-	1.56–1.70
He et al.^b	0.18–0.26	1.4–1.5	1.39–1.49
Mohr et al.^c	0.31	-	1.59
DeCarlo et al.^d	0.3–0.45	-	-
Note: The suffix “_v2” means in treating H2O^+ (m/z 18) and CO^+ (m/z 28), frag_18/28_v2 (Aiken et al. 2008) was used; “_v_i” means that the modified frag_18/28_v_i (see online supplemental information Section 2, Figures S2–S4, and Tables S1–S3) was used. The ratios of organic aerosols from biomass burning (BBOA) from the literature, using frag_18/28_v2, are also shown for comparison.
^aParticles from burning lodgepole pine and sage/rabbitbrush in Aiken et al. (2008).
^bParticles from burning six types of biomass, from rice straw to wood, in He et al. (2010).
^cParticles from burning paper in Mohr et al. (2009).
^dAmbient aerosols with biomass burning influence in DeCarlo et al. (2008).

Mohr , C. , Huffman , J. A. , Cubison , M. J. , Aiken , A. C. Docherty , K. S. 2009 . Characterization of Primary Organic Aerosol Emissions from Meat Cooking, Trash Burning, and Motor Vehicles with High-Resolution Aerosol Mass Spectrometry and Comparison with Ambient and Chamber Observations . Environ. Sci. Technol. , 43 : 2443 – 2449 .

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Aiken , A. C. , Decarlo , P. F. , Kroll , J. H. , Worsnop , D. R. , Huffman , J. A. Docherty , K. S. 2008 . O/C and OM/OC Ratios of Primary, Secondary, and Ambient Organic Aerosols with High-Resolution Time-of-Flight Aerosol Mass Spectrometry . Environ. Sci. Technol. , 42 : 4478 – 4485 .

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