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Ozone depleting substances – a story of science/policy/industry interaction

Stefan Reimann

A) General questions on CFC-11 and related policy

1. What is CFC-11 and for what purpose has it been used? 2. What is the global background concentration and how has it developed since 1978?3. What is the legislation within the Montreal Protocol in Europe/US (so-called A5 countries) and in the developing countries (so-called Non-A5 countries)?

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• The decoding system for F-123a is:• 1 = number of carbon atoms minus 1 (omitted if result is zero) • 2 = number of hydrogen atoms plus 1 • 3 = number of fluorine atoms • The rest are chlorine atoms• a = Letter added to identify isomers, the "normal" isomer has the smallest

mass difference between the carbon-atoms, and a, b, or c are added as the masses diverge from normal.

example : F-(0)11 ?

example : F-(0)22 ?

example: F-134a ?

Decoding system for CFCs/HCFCs/HFCs

The invention of CFCs~1930

~1930: Thomas Midgley invents the production and usage of CFCs

Also invents the usage of lead in car fuel

Historian John McNeill: "had more impact on the atmosphere than any other single organism in Earth's history

Industrial&Engineering Chemistry, May 1930

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The first published CFC measurements: 1971Atmospheric Environment (1972)

2000 Mio years ago: algae develop the ability to use the photosynthesis and produce oxygen as a by-product

About 600 Mio years ago enough O3 was in the stratosphere to protect lifefrom the UV radiation of the sun.Before life was only possible in the water.

Some oxygen molecules are degraded in the stratosphere through UV-radiation and form O-radicals, which form ozone.

O2 + UV => O + OO + O2 => O3

History of the ozone layer

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• Destruction of CFCs in the stratosphere

leads to chloro-radicals

• The further usage of CFCs could threaten

the ozone layer.

Nature, 1974

Chloro-radicals in the stratosphere1974

R. Stolarski R. Cicerone1971

Love

lock

, 197

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Continuous record of CFC measurementstoday

Adrigole and Mace Head (IRE)

MontrealProtocol

CFCs: ChlorofluorocarbonsCCl4, CH3CCl3: Chlorinated solvents HCFCs: HydrochlorofluorocarbonsHalons and CH3Br: containing bromine

Kyoto Protocol

HFCs: HydrofluorocarbonsPFCs: PerfluorocarbonsSF6: Sulfur hexafluoride

CFC-11

Global AGAGE network

Global NOAA network

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Substitution of CFCs

Daniel et al., JGR, 2007

2010global CFCphaseout

Pro

du

ced

Qu

anti

ty(k

t/yr

)

The 2019 Antarctic “ozone hole"http://ozonewatch.gsfc.nasa.gov/meteorology/index.html

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1.-3.: CFC-11 (CCl3F): usage and global background

USAGE:Hair spray, asthma spray, foam blowing

CFCs measured at Jungfraujoch with FTIR (remote sensing from ground)

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B) Questions related to the analytical chemistry of CFC-11

1. What is the sample volume for GC-ECD and GC-MS?2. What is the precision of GC-MD and GC-Medusa: check AGAGE data

base, calculate medians of Barbados for GC-MD (ECD) and of Zeppelin for GC-MEDUSA (MS) for 2017.

3. What volume of air do you have to sample for certainly detecting an increase in molar ratios of 1 ppt above the baseline?

Median: 0.08%0.19 ppt at 238 ppt

CAVE: precision in AGAGE is not "real" precision

Median: 0.09% Wüthrich (2019) 0.2%0.21 ppt at 238 ppt

4.5 ml 2000 ml

3 x 0.19 ppt = 0.57 ppt 2.6 ml 3 x 0.21 ppt = 0.63 ppt 1260 ml

B) Questions related to the analytical chemistry of CFC-11

1. CFC-11 can be analysed by GC-ECD or GC-MS. 2. What is the absolute limit of detection for CFC-11 on an ECD

and on a quadrupole MS using electron ionization (EI)6.5 pg

1.2 ng

Peak height : 280'000Baseline: +/- 30MW CFC-11: 136 g/mol230 ppt22.45 L/mol4.5 ml volume

6.5 pg

GC-ECD Instrument in Barbados

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B) Questions related to the analytical chemistry of CFC-11

45. Attached is an ECD chromatogram for the most important CFCs and chlorinated hydrocarbons. Which peak belongs to which mass spectra measured by electron ionization.

B) Questions related to the analytical chemistry of CFC-11

CFC-12CF2Cl2

120122

101103105

8587

CF2Cl2- 19 (F)

- 35/37 (Cl)#4

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B) Questions related to the analytical chemistry of CFC-11

CFC-11CF3Cl

#2

B) Questions related to the analytical chemistry of CFC-11

CFC-113CF2Cl-CFCl2

151153155

101103

CFCl2

- 35/37 (Cl)

#1

CF2Cl-CFCl2

186

C2F3Cl2CF2Cl +

- C-C bond

8587

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B) Questions related to the analytical chemistry of CFC-11

CH3-CCl3

117119121

9799

101

CCl3

- 35/37 (Cl)

#3

- 15 (CH3)

CH3-CCl3

132

CH3-CCl2CH2-CCl(CH-CCl)

6163

60/62

B) Questions related to the analytical chemistry of CFC-11

CCl4

117119121

828486

4749

CCl3

- 35/37 (Cl)

#5

CCl4

152- 35/37 (Cl)

CCl2CCl

- 35/37 (Cl)

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B) Questions related to the analytical chemistry of CFC-115. Could satellites also be used to detect sources? Which is the measurement principle?

Tetgmeier et al., EESD, 2016

LIMB sounders

C) Specific questions on CFC-11 and East-Asia

1. Which country is in the focus of newly producing the CFC-11 and for what purpose is it thought to be used (see report of eia)?

Montzka et al., Nature, 2018

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Global emission:12-box model

Concentrations

C) Specific questions on CFC-11 and East-AsiaONE STEP BACK: GLOBAL EMISSION ESTIMATION

CFC-12

CFC-11

CFC-113

CCl4

CH3CCl3

30th Anniversary of the Montreal Protocol

CFC-12

CFC-113

CH3CCl3

CCl4

CFC-11

C) Specific questions on CFC-11 and East-AsiaONE STEP BACK: GLOBAL EMISSION ESTIMATION

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Chapter 1, Ozone Assessment 2014

Year 2003 ff.: ~60 GgChapter 1, Ozone Assessment 2014

CFC-11 Emissions CFC-11 Banks

Year 2008: 1420 GgChapter 5, Ozone Assessment 2010

C) Specific questions on CFC-11 and East-AsiaONE STEP BACK: GLOBAL EMISSION ESTIMATION

30th Anniversary of the Montreal Protocol

Constant emissions: ~60 Gg/yr

2008-2016:1420 Gg bank should be

depleted by ~40%

Concentrations should beginto drop more rapidly in recent

years

C) Specific questions on CFC-11 and East-AsiaONE STEP BACK: GLOBAL EMISSION ESTIMATION

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30th Anniversary of the Montreal Protocol

Constant emissions: ~60 Gg/yr

2008-2016:1420 Gg bank should be

depleted by ~40%

Concentrations should begin to drop more rapidly in recent

years

Montzka et al., Nature, 2018• Changes in stratosphere?• Higher emissions?

Faster bank release? Losses from production?

C) Specific questions on CFC-11 and East-AsiaONE STEP BACK: GLOBAL EMISSION ESTIMATION

Emissions

CFC-12

CFC-11

CFC-113

CCl4

CH3CCl3

CFC-11: after 201313 Gg/yr new emissions

C) Specific questions on CFC-11 and East-AsiaONE STEP BACK: GLOBAL EMISSION ESTIMATION

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C) Specific questions on CFC-11 and East-Asia

Confirmed CFC-11 Production[eia, 2018]

CF

C-1

1

GCMS chromatogram of new foam[eia, 2018]

C) Specific questions on CFC-11 and East-Asia

Measurement from outside of China:GC-MD: sample volume 4.5 ml precision: 0.08 %Medusa: sample volume 2000 ml precision: 0.09 %238 ppt:

15 ug/m3 / 137.5 [g/mol] x 24.45 [L/mol] = 2.7 ppm in source region 0.54 ppt with 1/5 Mio not/maybe possible to detect above the background of 238 ppt

Measurement inside of China:Measurement site in China (Shangdianzi) and measurements around factories and sampling of newly produced foam and analysis, or plane campaigns, drones with canisters/bags.

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Possible Sources of CFC-11 from China

1Production of CFC-11 for foam blowing: ~ 10%-30% release during foam blowing:

With 13 kt of CFC-11 emissions ~40-130 kt of illegal production ~30% F-12 is produced as well, with 100 kt CFC-11 this would result in 30 kt

CFC-12 for which no use is there and which potentially will be emitted

Possible Sources of CFC-11 from South-East Asia

2Formation of CFCl3 during CHCl3 CHF2Cl (R-22) productiona) with HF: H-abstraction, highly unlikelyb) with F2: H-abstraction, text book knowledge

Is F2 built in the reaction CHCl3 + HF CHF2Cl?Is F2 used instead of HF in the reaction?

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Jungfraujoch Nov 2017Influence from an Italian HCFC-22 factory

CF4

HCFC-22

HFC-23

CFC-11

Possible Sources of CFC-11 from South-East Asia

3Formation of CFCl3 during CHF2Cl (R-22) production due to impurities of CCl4 in the CHCl3.

How good is the cleaning process? Has something changed?

Beauty of this suggestion:- No CFC-12 is produced (only marginal global emission increase seen and definitely less than 30 Gg/yr)- CFC-11 could then be used for foam blowing- or CFC-11 has a bp of 26 °C vs. CCl4 of 76 °C and hence can be vented easily into the atmosphere.

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HCFC‐133aHCFC‐133a

Other newly found issues around halocarbons in the atmosphere

New HCFC 133a detected by Univ. East Anglia (Laube et al., 2014) a follow-up (Vollmer et al., 2015, GRL)

HCFC‐31HCFC‐31

New HCFC-31 detected by Empa (Schönenberger et al., 2015, GRL)

Other newly found issues around halocarbons in the atmosphere

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HCFC‐133aHCFC‐133aHCFC‐31HCFC‐31

Other newly found issues around halocarbons in the atmosphere

Global Emissions related to the measurements and a global 12‐box model

MethyleneChloride

HCFC-31 (Chlorofluoromethane)

HFC-32 (Difluoromethane)

Trichloroethylene

HCFC-133a(Chlorotrifluoroethane)

HFC-134a (Tetrafluoroethane)

HCFC‐133aHCFC‐133aHCFC‐31HCFC‐31

HF

HF

HFHF

HF

New HCFCs: SourceBy-product of chemical production

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Inverse Modelling of GHG Emissions CEP Seminar, 2017-05-08, Bern stephan.henne@empa.ch

CO

CO

CO

CO

CO

CO

CO

CO

CO

F-134a

F-125

F-134a

F-134a

F-152a

Select fair-weather conditionswith weak synoptic forcing but strong thermally inducedtransport from Swiss Plateau toJungfraujoch

Etarget (CH)CO (observed)target (observed)

= ECO (CH Inventory)

Estimation of Swiss Halocarbon EmissionsTracer-ratio methodEstimation of Swiss Halocarbon EmissionsTracer-ratio method

Inventories vs. measurement-based emissions:HFC-134a and HFC-125 from Switzerland

Source: Empa 2017National Swiss Inventory Report, submission: April 2017

Estimate based on measurements at Jungfraujoch (Alps)

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170

HFC-23 CHF3

Lifetime: 228 yrGWP: 14 800

Jungfraujoch for checking European emissions of HFCs

Concept: all variability is attributed to plant emissions

1. Assume that variability only originates from emissions from known point sources2. Calculate point source emissions for all events individually3. Fit obtained emissions to a log-normal distribution

Time-dependent source:

Jungfraujoch for checking European emissions of HFCs

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Spinetta-MarengoSolvay

HFC-23 emissions estimated from Europe

Keller et al., GRL, 2011

Le Monde 27.08.2011

Corriere della sera 01.09.2011

Tagesanzeiger 19.08.2011

HFC-23 emissions estimated from Europe: reactions

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Velders et al., Science (2012)

CFCs/HCFCs/HFCs in the future

The Kigali Amendment:non-ozone depleting HFCs in the Montreal Protocol

HFC consumption will be down-seized to 15%

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Velders et al., Science (2012)

CFCs/HCFCs/HFCs in the future

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Foam productionAir conditioning (cars)

GWP100: <1 GWP100: <1

Possible Problems:

-HCFC-22/CCl4 used in production process

-Formation of stable trifluoroacetic acis (v.a. HFO-1234yf)

-A playground for new chlorinated substances (HCFOs)

New substances are proposed by industry Short-lived HFCs (industry: HFOs)

Jungfraujoch, Switzerland, 2011

HFC-1234ze: the first measurement world-wide:Jungfraujoch, February 2011

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Vollmer et al., GRL, 2016, update

HFC-1234yf/-1234ze/-1233zd: The "new kids on the block"

Trifluoroacetic acid formation from HOFs

(Hurley et al., 2008)

+Cl +OH

HFC-1234yfHFC-1234yf

trifluoroacetyl fluoride (TFF)trifluoroacetyl fluoride (TFF)

trifluoroacetic acid (TFA)trifluoroacetic acid (TFA) Wet depositionDry deposition similar to HNO3

Removal

hydrolysishydrolysis

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Trifluoroacetic acid

F-1234yf catches fire at Mercedes Hydrofluoric acid

HFC-1234yf: more harm than benefits?