Biomass burning contribution to ambient air particulate levels at Navrongo in the Savannah zone of Ghana

Figures & data

Figure 1. Map showing the monitoring site in Navrongo, Ghana.

Figure 2. (a) Monthly mean PM_2.5 mass concentrations. (b) Monthly mean rainfall measured in Navrongo.

Table 1. Summary statistics for the species measured at Navrongo (μg/m³)

Species^a	Arithmetic mean^b	Standard deviation^b	Maximum^b	Minimum^b	Detection limit	Number of BDL Values (%)	S/N ratio
PM2.5 (μg/m^3)	32.4	14.96	88.01	7.14	1.30	0.00	32.70
OC1 (μg/m^3)	1.32	1.05	6.70	0.18	0.42	0.00	0.80
OC2 (μg/m^3)	4.79	2.48	19.49	0.57	0.42	0.00	8.00
OC3 (μg/m^3)	3.04	1.47	10.76	0.42	0.42	0.00	11.00
OC4 (μg/m^3)	1.11	0.63	3.27	0.17	0.42	0.90	2.10
EC1 (μg/m^3)	0.56	1.39	14.14	0.02	0.06	1.80	26.00
EC2 (μg/m^3)	0.46	0.32	2.20	0.00	0.06	2.70	0.90
OP (μg/m^3)	1.11	0.80	5.05	0.06	0.06	0.90	2.20
Na (μg/m^3)	0.42	0.22	1.01	0.10	0.15	0.00	6.70
Mg (μg/m^3)	0.17	0.14	0.61	0.005	0.008	0.00	13.10
Al (μg/m^3)	1.46	1.10	5.04	0.17	0.09	0.00	121.50
Si (μg/m^3)	3.03	2.87	1.13	0.1	0.02	0.00	153.20
S	201.0	75.0	411.0	25.0	53.8	0.00	130.40
Cl	706.0	1200.0	5410.0	18.0	29.7	0.00	94.30
K	508.0	317.0	1420.0	10.0	22.4	0.00	77.10
Ca	602.0	578.0	2500.0	55.0	14.7	0.00	89.50
Ti	133.0	105.0	489.0	9.0	3.7	0.00	45.60
V	2.0	2.0	9.0	0.0	0.8	0.00	2.70
Cr	19.0	6.0	61.0	6.0	6.0	0.00	23.90
Mn	44.0	26.0	145.0	13.0	1.4	0.00	39.90
Fe	1570	876	4510	501	52.4	0.00	72.50
Ni	57.0	18.0	185.0	21.0	14.1	0.00	17.80
Cu	189.0	61.0	615.0	66.0	6.3	0.00	34.40
Zn	110.0	37.0	344.0	37.0	24.6	0.00	43.10
Br	26.0	9.0	84.0	7.0	3.7	0.00	21.70
Rb	3.0	2.0	9.0	1.0	0.6	5.40	1.20
Sr	14.0	7.0	41.0	1.0	1.5	0.90	3.40
Pb	31.0	6.0	98.0	11.0	8.9	0.00	13.70
Notes: ^aAll values in ng/m^3 except as noted for specific species.
^bBlank values were deducted from the initial concentration values.

Table 2. PM_2.5 mass concentration values and the composition of the identified species at Navrongo compared with that of other studies (ng/m³)

Species	This study	Ashaiman (Accra, Ghana)^a	Kwabenya (Accra, Ghana)^b	Al Zamalek (Egypt)^c
PM2.5 (μg/m^3)	32.4	21.56	40.8	61.9
OC (μg/m^3)	11.36	6.31
EC (μg/m^3)	0.95	2.04
Na (μg/m^3)	0.42	0.74	—	—
Mg (μg/m^3)	0.17	0.09	—	—
Al (μg/m^3)	1.46	0.81	0.83	0.12
Si (μg/m^3)	3.03	1.16	0.17	0.30
S	201	391.3	462	—
Cl	706	144.5	123	—
K	508	486.8	377	500
Ca	602	287.2	144	200
Ti	133	59.0	37.5	—
V	2.0	2.9	1.9	—
Cr	19.0	17.3	2.7	—
Mn	44.0	27.4	7.6	—
Fe	1570	987.3	289	200
Ni	57.0	54.4	3.2	—
Cu	189	180.1	4.1	—
Zn	110	164.4	6.5	—
Br	26.0	32.4	5.9	—
Rb	3.0	2.1	1.4	—
Sr	14.0	7.2	2.9	—
Pb	31.0	43.9	2.5	700
Notes: ^aOfosu et al. (2012),
^bAboh et al. (2009),
^c Abu-Allaban et al. (2002).

Table 3. Ratio of carbon fractions to total carbon and PM_2.5 particulate mass

Species fractions (%)	Mean	Min	Max
EC/OC	8.6	1.5	26.9
OC/TC	92.3	22.6	99.8
EC/TC	7.4	1.5	36.8
OC/Mass	37.9	4.9	87.8
EC/Mass	3.9	1.1	13.4
TC/Mass	41.2	4.9	89.3

Table 4. Concentration values of PM_2.5 and carbon species (μg/m³) for Harmattan and non-Harmattan periods

	Harmattan (H)	Non-Harmattan (n-H)	Ratio (H/n-H)
Mass	58.36	34.18	1.71
OC1	2.03	0.90	2.25
OC2	6.15	3.98	1.55
OC3	3.91	2.53	1.55
OC4	1.40	0.93	1.50
EC1	1.10	0.25	4.49
EC2	0.65	0.34	1.93
OP	1.53	0.85	1.80
OC	14.76	9.16	1.61
EC	1.73	0.57	3.06
TC	16.48	9.71	1.70

	Al	Si	S	K	Ca	Ti	Mn	Fe	Cu	Zn	Pb	OC	EC
Al	1.00
Si	0.98	1.00
S	0.41	0.36	1.00
K	0.86	0.86	0.58	1.00
Ca	0.95	0.98	0.36	0.87	1.00
Ti	0.99	0.96	0.39	0.84	0.94	1.00
Mn	0.95	0.93	0.42	0.89	0.93	0.96	1.00
Fe	0.97	0.94	0.44	0.88	0.94	0.97	0.99	1.00
Cu	0.29	0.21	0.37	0.37	0.25	0.26	0.46	0.45	1.00
Zn	0.36	0.27	0.42	0.42	0.31	0.32	0.50	0.50	0.97	1.00
Pb	0.29	0.20	0.39	0.37	0.23	0.27	0.45	0.44	0.91	0.88	1.00
OC	0.20	0.19	0.34	0.43	0.23	0.18	0.37	0.33	0.67	0.65	0.61	1.00
EC	0.02	0.05	0.20	0.32	0.09	0.01	0.18	0.13	0.42	0.39	0.37	0.86	1.00

Table 6. Average source contributions to PM_2.5 mass concentrations at Navrongo

Source		Mean source contribution (μg/m^3)	Standard deviation (μg/m^3)	Fractional source contribution (%)
1	Two-stroke engines	3.4	2.4	9.9%
2	Gasoline emissions	3.7	2.8	10.9%
3	Soil dust	12.3	6.2	35.9%
4	Diesel emissions	3.9	2.5	11.5%
5	Biomass	5.4	4.4	15.8%
6	Resuspended road dust	5.5	5.4	16.0%

Figure 3. Source profiles deduced from the PMF analysis of data for Navrongo, Ghana.

Figure 4. Source contributions deduced from the PMF analysis of data for Navrongo, Ghana.

Abu-Allaban , M. , Gertler , A.W. and Lowenthal , D.H. 2002 . A preliminary apportionment of the sources of ambient PM10, PM2.5, and VOCs in Cairo . Atmos. Environ. , 36 : 5549 – 5557 . doi: 10.1002/xrs.1172

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