Newly detected ozone-depleting
substances in the atmosphere
SAP Presentation
OEWG, Paris, 14-18 July 2014
These gases are listed in the
Montreal Protocol.
•
•
•
•
CFC-112 (CFCl2CFCl2) – under Annex B
CFC-112a (CF2ClCCl3) – under Annex B
CFC-113a (CF3CCl3) – under Annex A
HCFC-133a (CF3CH2Cl) – under Annex C.
Regulated under Article 2F
What are these newly found
compounds?
Lifetime
years
Formula
Rad. Eff.
ODP Wm-2ppb-1
100-y
GWP
50-y
GTP
4750
5480
CFC-11
CFCl3
52
1.00
0.25
CFC-112
CFCl2CFCl2
59
0.88
ab0.29
CFC-112a
CF2ClCCl3
51
0.88
–
–
–
CFC-113a
CF3CCl3
59
0.68
a0.23
a3310
a3920
4
0.02
a0.15
a340
a74
HCFC-133a CF3CH2Cl
aOnly
ab3840 ab4540
one study to date. bBased on a mixture of -112 and -112a
GWPs and radiative efficiencies
are derived from a new study by
Etminan et al. (2014).
How are these newly found
CFC-112 and -112a compounds evolving?
are both declining
0.6
4
Mixing Ratio (ppt)
CFC-112a
3
0.6 44 yr
1 0.2
CFC-113a and HCFC1965 1975 1985
133a are increasing
rapidly 0.5 CFC-113a
1995 2005
1965 1975 1985 1995 2005
0.4
3
51 yr
0.2
0.1
0.0
1965 1975 1985 1995 2005
Laube et al. (2014) Figure 1
0.0
0 0.0
0.0
Emissions are
0.3
increasing
0.1
2 0.4
0.2
0.4
0.8
2
0.3
HCFC-133a
4.3 yr
0.2
6
4
1 0.1
2
0 0.0
0
1965 1975 1985 1995 2005
Annual Emissions (Gg)
CFC-112
Emissions have also 51 yr
0.4
declined
0.2
The levels of the new compounds
are not particularly high when
measured against other ODSs
• These are not new compounds, but now detected
in the atmosphere
• Current 2013 levels of global effective equivalent
stratospheric chlorine (EESC) is about 1700 parts
per trillion (ppt)
• The maximum contribution of these new CFCs is
about 4 ppt of EESC - this is <0.2% of the global
EESC total.
• The maximum 2011 emissions contribution is
about 8,000 Gg CO2-Eq per yr. This is <0.5% of
the global 2011 ODS GWP weighted emissions.
What are the sources?
• CFC-112 and -112a (decreasing): may have
been used as feedstock chemicals for fluorovinyl
ether production and also as solvents for cleaning
electronics. For CFC-112, 1989-2001 production
has been reported but only small quantities. No
CFC-112a production reports have been released
- it may have been reported as CFC-112.
• CFC-113a (increasing): emissions could be
related to usage as an intermediate for HFC-134a
production. Also used as a feedstock for
insecticide production (cyhalotrin and tefluthrin).
• HCFC-133a (increasing): used in the production
of pharmaceuticals and is an intermediate product
in HFC-134a production (TEAP, 2012).
Summary
• CFC-112, CFC-112a, CFC-113a, HCFC-133a have been
newly discovered by analysis of air samples and from air
trapped in snow. These compounds are included under the
Protocol.
• All of these gases are ozone depleting substances and
greenhouse gases.
• Concentrations are currently quite small in comparison to
levels of other ODSs in the atmosphere. Not currently
significant for ozone depletion and climate forcing.
• CFC-112 and CFC-112a are decreasing
• CFC-113a and HCFC-133a are increasing
• Details on these gases will be found in the SAP 2014
Scientific Assessment
Thank you for your attention!
Thanks for contributions from
Keith Shine, Johannes Laube, Guus Velders,
Lambert Kuijpers, David Sherry,
Stefan Reimann, Maryam Etminan
Other matters
• HFO-1233zd, lifetime = 40 days,
– ODP = 0.00034 (strongly dependent on
emission location)
Name
Formula
Lifetime
(years)
ODP
GWP100
GTP-50
HCFC-225ca
CHCl2CF2CF3
1.9
0.02
127
22
HCFC-225cb
CHClFCF2CClF2
5.9
0.03
525
120