Geoscience Reference
In-Depth Information
Table 11.2. Mixing ratios in 2010, overall lifetimes from emission to removal, and 100-year global warming
potentials of selected chlorocarbons, bromocarbons, and fluorocarbons
Estimated
100-year
overall
global
Tropospheric
atmospheric warming
Chemical
Trade
mixing ratio
lifetime
potential
formula
name
Chemical name
(pptv)
(yr)
(GWP)
CHLOROCARBONS AND CHLORINE COMPOUNDS
Chlorofluorocarbons (CFCs)
CFCl 3 (g)
CFC-11
Trichlorofluoromethane
241
45
4,750
CF 2 Cl 2 (g)
CFC-12
Dichlorodifluoromethane
531
100
10,900
CFCl 2 CF 2 Cl(g)
CFC-113
1-Fluorodichloro,2-difluorochloroethane
77
85
6,130
CF 2 ClCF 2 Cl(g)
CFC-114
1-Difluorochloro,2-difluorochloroethane
17
300
10,000
CF 2 ClCF 3 (g)
CFC-115
1-Difluorochloro,2-trifluoroethane
8
1,700
7,370
Hydrochlorofluorocarbons (HCFCs)
CF 2 ClH(g)
HCFC-22
Chlorodifluoromethane
251
11.8
1,810
CH 3 CFCl 2 (g)
HCFC-141b
2-Fluorodichloroethane
18
9.3
725
CH 3 CF 2 Cl(g)
HCFC-142b
2-Difluorochloroethane
21
17.9
2,310
Other Chlorocarbons
CCl 4 (g)
Carbon tetrachloride
88
26
1,400
CH 3 CCl 3 (g)
Methyl chloroform
7.3
4.8
146
CH 3 Cl(g)
Methyl chloride
580
1.3
13
Other Chlorinated Compounds
HCl(g)
Hydrochloric acid
10-1,000
< 1
-
BROMOCARBONS
Halons
CF 3 Br(g)
H-1301
Trifluorobromomethane
2.9
65
7,140
CF 2 ClBr(g)
H-1211
Difluorochlorobromomethane
4.1
16
1,890
CF 2 BrCF 2 Br
H-2402
1-Difluorobromo,2-difluorobromoethane
0.7
20
1,640
Other Bromocarbons
CH 3 Br(g)
Methyl bromide
8
0.7
5
FLUOROCARBONS AND FLUORINE COMPOUNDS
Hydrofluorocarbons (HFCs)
CHF 3 (g)
HFC-23
Trifluoromethane
22
270
14,800
CHF 2 CF 3 (g)
HFC-125
Pentafluoroethane
3.7
29
3,500
CH 2 FCF 3 (g)
HFC-134a
1-Fluoro,2-trifluoroethane
35
13.6
1,430
CH 3 CHF 2 (g)
HFC-152a
1,1-Difluoroethane
4
1.4
124
Perfluorocarbons (PFCs)
CF 4 (g)
PFC-14
Tetrafluoromethane
74
50,000
7,390
C 2 F 6 (g)
PFC-116
Perfluoroethane
3.5
10,000
12,200
Other Fluorinated Compounds
SF 6 (g)
Sulfur hexafluoride
7.2
3,200
22,800
Sources :International Panel on Climate Change (IPCC) (2007, Tables 2.1 and 2.14); Mauna Loa Data Center (n.d.).
11.5.1. Chlorofluorocarbons and Related
Compounds
( CFCs ). Table 11.2 identifies important CFCs, which
are gases formed synthetically such as by replacing
one or more chlorine atoms with fluorine atoms in car-
bon tetrachloride [CCl 4 (g)]. For example, CFC-12
[CF 2 Cl 2 (g), dichlorodifluoromethane] can be formed
The compounds that play the most important role in
reducing stratospheric ozone are chlorofluorocarbons
 
 
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