PM_2.5 Emissions from Aluminum Smelters: Coefficients and Environmental Impact

Figures & data

Figure 1. Illustration of an electrolysis pot with the raw pot gases recovered and treated at the GTC with alumina. Unrecovered pot gases are vented through the roof of each potroom. This is where CYCLEX, which measures PM_2.5 and CPM, is located.

Figure 2. Picture of the modified PM_2.5 sizer for gas recovery in a potroom.

Figure 3. Location of Alma smelter and its two air monitoring stations. Arrows indicate the prevailing winds.

Table 1. Comparisons of mean PM emission coefficients ± standard error of the mean at the Sebree smelter between (1) EPA CTM040/202 and OTM27/28 at GTC and FTC, and between (2) the M14* and Rio Tinto Alcan CYCLEX candidate method at roof vents

	CPM	PM2.5	PM10	PMtotal
FTC
2006 (n = 5) EPA CTM040/202	45.4 ± 7.9	47.0 ± 8.0	47.5 ± 8.1	47.8 ± 8.2
2008 (n = 3) OTM27/28	16.8 ± 4.3	17.1 ± 4.1	17.3 ± 4.1	17.6 ± 4.0
GTC
2006 (n = 4) EPA CTM040/202	121 ± 44	130 ± 46	137 ± 45	149 ± 43
2008 (n = 3) OTM27/28	48 ± 7	55 ± 7	63 ± 7	86 ± 12
Roof vents
2007 and 2008 (n = 17) M14*	273 ± 30	417 ± 39	—	1308 ± 129
2007 and 2008 (n = 32) CYCLEX	251 ± 21	356 ± 29	—	1634 ± 207
Notes: Data presented in g·t^−1 Al.

Table 2. Ratios of CPM and PM_2.5 to PMtotal for the Rio Tinto Alcan Sebree smelter

Location	Ratio	CPM (%)	PM2.5 (%)
FTC	(CPM or PM2.5)/PMtotal	95	97
	(CPM or PM2.5)/total PM2.5	3	4
GTC	(CPM or PM2.5)/PMtotal	55	64
	(CPM or PM2.5)/total PM2.5	11	11
Roof Vents	(CPM or PM2.5)/PMtotal	21	32
	(CPM or PM2.5)/total PM2.5	56	85
Notes: GTC/FTC and roof vent results are respectively based on OTM27/28 and M14* sampling methods. PMtotal represents the total PM emissions for each sector (FTC, GTC, and roof vents), whereas “total PM2.5” is the sum of PM2.5 emissions for all of these sectors.

Table 3. Two-say ANOVA on PM_2.5 measuements at roof vents as affected by the year (2007 vs.2008 and the method (M14* vs. CYCLEX)

Sources	dF	SS	F-value	P
Year	1	0.0269	1.44	0.2403
Method	1	0.0103	0.55	0.4639
Year x method	1	0.0093	0.50	0.4854
Residual	30	0.5619

Table 4. PM_2.5 mass fraction of various inorganic species (species mass on the filter/total mass of PM_2.5 on the filter—in percent) at the smelter stacks (FTC and GTC) and in its surrounding environment (urban stations 1A and 3 A)

	Mass Fraction (%)
Species	FTC	GTC	Ambient Station 1A	Ambient Station 3A
Cr	<0.01	0.04	0.07	0.18
Fe	0.05	0.16	0.46	1.18
Ga	<0.01	<0.01	<0.01	<0.01
Mg	0.01	0.02	0.17	0.49
Mn	<0.01	<0.01	0.04	0.06
Ti	<0.01	<0.01	0.03	0.11
V	<0.01	0.01	0.02	0.02
Zn	0.29	0.25	0.12	0.49
Zr	<0.01	<0.01	<0.01	<0.01
Si	<0.01	<0.01	<0.01	4.34
Pb	0.24	<0.01	<0.01	<0.01
Li	<0.01	<0.01	0.01	0.01
Ni	0.03	0.08	0.03	0.05
Al	0.08	13	1.74	4.05
Be	<0.01	<0.01	<0.01	<0.01
Ca	0.03	0.08	0.74	3.61
Cd	<0.01	<0.01	<0.01	<0.01
Cu	0.01	0.22	0.29	4.01
Na	0.20	3.7	1.97	4.77
F	0.05	2.9	0.39	0.40
Total	0.98	20	6.1	24
Others	99	80	94	76

Figure 4. SEM-EDX on GTC and urban station filters. Picture of spotted area on filters and diagram of elemental determination. EDX analysis on (a) the GTC filter, (b) the urban station 1A filter, and (c) the urban station 1A filter.

Figure 5. Lead isotope diagram for samples in the carbon raw material (anode), at the stack output (GTC), and in the surrounding environment of the smelter (station) compared with North American aerosols. Adapted with permission from Poirier.29 Copyright 2006 Elsevier, Earth and Planetary Science Letters.

Figure 6. Osmium-lead isotope diagram for samples in the carbon raw material (anode), at the stack output (GTC), and in the surrounding environment of the smelter (station).

Poirier , A. 2006 . Re-Os and Pb Isotope Systematics in Reduced Fjord Sediments from Saanich Inlet (Western Canada) . Earth Planet. Sci. Lett. , 249 : 119 – 131 .

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