Springtime influences of Asian outflow and photochemistry on the distributions of diacids, oxoacids and α-dicarbonyls in the aerosols from the western North Pacific Rim

Figures & data

Fig. 1. A map of East Asia with sampling location of Cape Hedo, Okinawa, Japan.

Fig. 2. Plots of 5-day backward air mass trajectories (BT) (a) daytime, (b) night-time, (c) early morning, (d) late morning, (e) early afternoon and (f) late afternoon arriving in Cape Hedo at 500 m above the ground level (AGL) during the study periods.

Fig. 3. Temporal variations in the concentration of (a) Total diacids (b) oxalic acid (C₂), (c) malonic acid (C₃), (d) succinic acid (C₄), (e) adipic acid (C₆), (f) pimelic acid (C₇), (g) azelaic acid (C₉), (h) phthalic acid, (i) terephthalic acid (tPh), (j) maleic acid (M), and (k) fumaric acid (F) in the ambient aerosols from Cape Hedo, Okinawa in spring 2007.

Table 1. Concentrations of diacids, oxoacids, benzoic acid and α-dicarbonyls in the TSP samples collected from Okinawa in spring, 2007.

Concentrations (ng m^−3)
Species	Range	AV ± SD
	Diacids
Oxalic (C2)	22–574	231 ± 123
Malonic (C3)	2.9–112	41 ± 25
Succinic (C4)	4.2–92	32 ± 23
Glutaric (C5)	1.1–27	6.0 ± 5.1
Adipic (C6)	0.44–11	2.8 ± 2.2
Pimelic (C7)	0.00–7.3	0.77 ± 1.1
Suberic (C8)	0.00–3.3	0.34 ± 0.52
Azelaic acid (C9)	0.00–5.7	2.0 ± 1.1
Methylmalonic (iC4)	0.03–4.3	1.1 ± 0.78
Methylsuccinic (iC5)	0.41–7.4	2.4 ± 1.6
2-Methylglutaric (iC6)	0.00–1.7	0.43 ± 0.42
Maleic (M)	0.26–8.9	2.1 ± 1.9
Fumaric (F)	0.35–11	1.8 ± 2
Methylmaleic (mM)	0.00–7.2	1.2 ± 1.5
Phthalic acid (Ph)	0.42–36	7.0 ± 7.8
Isophthalic (iPh)	0.02–5.4	0.93 ± 1.1
Terephthalic (tPh)	0.09–14	2.2 ± 2.7
Malic (hC4)	0.02–9.5	1.4 ± 1.7
Oxomalonic (kC3)	0.04–32	5.8 ± 6.3
4-Oxopimelic (kC7)	0.3–14	3.1 ± 2.7
	Oxoacids
Glyoxylic (ωC2)	2.0–98	26 ± 20
3-Oxopropanoic (ωC3)	0.00–0.78	0.08 ± 0.14
4-Oxobutanoic (ωC4)	0.00–7.2	2.0 ± 2.0
9-Oxononanoic(ωC9)	0.23–6.5	2.3 ± 1.5
Pyruvic (Pyr)	0.53–52	6.0 ± 8.5
	Aromatic monoacid
Benzoic acid (Bz)	3.2–53	18 ± 9.0
	α-Dicarbonyls
Glyoxal (Gly)	0.59–17	4.1 ± 3.7
MeGly (MeGly)	0.49–41	4.8 ± 6.5

Fig. 4. Temporal variations in the concentration of (a) glyoxylic acid (ωC₂), (b) 3-oxopropanoic acid (ωC₃), (c) 4-oxobutanoic acid (ωC₄), (d) 9-oxononanoic acid (ωC₉), (e) pyruvic acid (Pyr), (f) methylglyoxal (MeGly), (g) glyoxal (Gly) and (h) benzoic acid (Bez) in the ambient aerosols from Cape Hedo, Okinawa in spring 2007.

Fig. 5. Diurnal variations in the concentration of (a) oxalic acid (C₂), (b) malonic acid (C₃), (c) succinic acid (C₄), (d) adipic acid (C₆), (e) azelaic acid (C₉), (f) maleic acid (M), (g) fumaric acid (F), (h) phthalic acid (Ph), (i) terephthalic acid (tPh), (j) glyoxylic acid (ωC₂), (k) 4-oxobutanoic acid (ωC₄), (l) 9-oxononoic acid (ωC₉), (m) pyruvic acid (Pyr), (n) methylglyoxal (Gly), (o) glyoxal (MeGly) and (p) benzoic acid (Bez) in the ambient aerosols collected at Cape Hedo, Okinawa in spring 2007.

Fig. 6. Spring time average relative abundance (%) of diacid species in total diacids in aerosols collected at Cape Hedo in 2007.

Fig. 7. Schematic diagram of atmospheric aging of selected diacids, oxoacids and α-dicarbonyls at Cape Hedo, Okinawa in the western North Pacific Rim.

Fig. 8. Temporal variations in the relative abundances of (a) C₂/total diacids and C₄/total diacids (b) diurnal variations in the relative abundances of C₂/total diacids and C₄/total diacids in the ambient aerosols collected at Cape Hedo, Okinawa. Colours indicate similar as other figures.

Fig. 9. Scatter plots between relative abundances of oxalic acid (C₂/total diacids) and its precursors compounds (a) malonic (C₃), (b) succinic (C₄), (c) glutaric (C₅) (d) adipic (C₆), (e) pimelic (C₇) and (f) azelaic (C₉) acids in night-time during 27 March–1 April and 11–13 April, 2007.

Fig. 10. Diurnal variations in the concentration ratios of (a) oxalic/malonic (C₂/C₃), (b) oxalic/succinic (C₂/C₄), (c) oxalic/glyoxal (C₂/Gly), (d) malonic/succinic (C₃/C₄), (e) oxalic/methylglyoxal (C₂/MeGly), (f) oxalic/pyruvic (C₂/Pyr) and (g) oxalic/ glyoxylic (C₂/ωC₂) in the ambient aerosols collected at Cape Hedo, Okinawa.

Table 2. Results of principal component analysis (varimax rotaion with Kaiser Normalization) on concentration of the selected diacids and related compounds and major ions in the aerosols collected in Cape Hedo, Okinawa in spring, 2007.

	Daytime				Night-time			24 h
	PC1	PC2	PC3	PC4	PC1	PC2	PC3	PC1	PC2	PC3
Species	Secondary formation	Marine	Industry and animal excreta	Vehicular emission	Secondary formation	Marine, dust and biomass	Industry and animal excreta	Secondary formation	Dust	Marine
C2	0.90	−0.03	0.31	0.25	0.77	0.13	0.60	0.49	0.63	−0.41
C3	0.90	−0.10	0.10	0.13	0.82	−0.14	0.51	0.59	0.58	−0.34
C4	0.89	−0.13	0.07	0.22	0.85	−0.02	0.49	0.8	0.49	−0.16
C6	0.89	0.09	0.02	0.26	0.87	0.30	0.32	0.82	0.42	0.12
C7	0.85	0.35	−0.31	0.09	0.93	0.19	−0.11	0.63	0.62	0.01
C9	0.00	−0.34	−0.10	−0.75	0.98	−0.12	0.00	0.62	0.02	−0.22
Ph	0.79	0.26	−0.22	0.28	0.87	0.36	0.09	0.85	0.39	0.22
tPh	0.06	0.39	0.09	0.70	0.57	0.50	0.36	0.82	0.49	−0.01
ωC2	0.86	−0.05	0.50	−0.05	0.75	0.28	0.59	0.84	0.48	−0.09
Pyr	0.88	0.11	0.23	−0.15	0.77	0.06	0.59	0.64	0.49	−0.21
Bez	−0.20	0.78	0.36	−0.23	−0.06	−0.82	−0.24	0.72	0.14	−0.43
Gly	0.91	0.09	0.17	−0.07	0.77	0.40	0.43	0.92	0.25	0.16
MeGly	0.87	0.07	−0.32	−0.25	0.87	0.31	0.12	0.59	0.70	−0.08
Na^+	0.10	0.90	−0.28	0.18	0.08	0.97	−0.06	0.02	0.04	0.98
NH4^+	−0.07	−0.36	0.92	0.09	0.06	−0.32	0.93	0.75	0.24	−0.37
MSA^−	0.49	−0.25	−0.18	0.69	0.94	−0.01	0.09	0.44	0.69	−0.20
NO3^−	0.38	0.63	−0.26	−0.02	0.78	0.44	−0.12	0.47	0.73	0.16
nss-SO4^2−	0.22	−0.13	0.96	−0.07	0.14	0.22	0.92	0.53	0.55	−0.45
ss-SO4^2−	0.10	0.94	−0.20	0.14	0.08	0.97	−0.06	0.02	0.04	0.98
nss-K^+	0.47	−0.51	0.68	0.24	0.33	0.90	0.07	0.52	0.24	−0.61
nss-Ca^2+	0.18	0.84	−0.16	0.33	0.36	0.82	0.14	0.02	0.90	0.14
Cl^−	−0.11	0.88	−0.29	0.36	−0.08	0.85	−0.45	−0.05	−0.03	0.97
% of variance	40	28	11	5.5	57	23	10	59	18	6.0