janet f. bornman co-chair, environmental effects assessment panel (eeap) of the montreal protocol...
TRANSCRIPT
Janet F. Bornman
Co-Chair, Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol
Curtin UniversityPerth, Western Australia [email protected]
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Workshop on Hydrofluorocarbon (HFC) Management
Montreal Protocol
Paris, 11-12 July 2014
Hydrochlorofluorocarbons (HCFCs)
Ozone Depleting Substances (ODS)Greenhouse Gases (GHGs)
Hydrofluorocarbons (HFC)
Greenhouse Gases (GHGs)
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The effect of HFC and HCFCs on the biosphere
Do they have an effect on the biosphere?
UV-generated hydroxyl radicals (OH), determine the atmospheric lifetime of climate-relevant compounds including: HFCs, HCFCs, CO, NOx, and SO2, methane ….
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The effect of HFC and HCFCs on the biosphere
Levels of complexity
UV radiation, ozone, climate, health, environment
HCFCs enter the body by inhalation of air, or by skin contact: breathing difficulties, skin irritation, may affect other internal organs
Ground-level O3, aerosols
UV
NOx Volatile organic compounds
Premature mortality (annual, global) ~1.5 million from particulate matter (sulfate, nitrate, most organic aerosols)~0.5 million from O3 (OECD, 2013)
Agricultural losses of $12-21 billion (Avnery et al., 2011)Complex sensitivity to UV radiation and climate
Air quality and UV radiation
Documented: Effects of decreased O3 and increased UV radiation
Not yet well documented:How will the environment/biosphere be affected by increased O3 and decreased UV radiation?
And how will climate interactions modify the response?
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Predicted likely decrease in tropospheric OH
Lower OH implies slower removal of many important gases:
HFCs, HCFCs, other VOCs, methane, NOx, SO2
Ozone and climate implications
Trifluoroacetic acid (TFA), a breakdown product of HCFCs and HFCs in the atmosphere
Readily deposits to the Earth’s surface through dry and wet deposition
Some of the new hydrofluoroolefins (HFO, unsaturated HFCs) as replacements for HFCs can lead to increases
in TFA (HFO TFA)
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The effect of HFC and HCFCs on the biosphere
Salt lakes with no outflow, loss by evaporation only Microbiological
degradation in soil and water
TFA
HFCs, HFOs, and HCFCsCF3-CXyH
O
CF3-C-OH
O
CF2Cl-C-OH
• Strong acid, forms salts with minerals in soil
• Concentrations in flowing water are small
• Accumulation will occur in salt lakes, playas and in the ocean
TFA - Environments at risk
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The effect of HFC and HCFCs on the biosphere
Trifluoroacetic acid (TFA)
Phytotoxic - negative effects on plant growth
But concentrations not sufficient for observed effects
Time (days)-10 0 10 20 30 40 50 60
Leng
th o
f w
ater
milf
oil (
cm)
0
5
10
15
20
25
30
35Control 100 μg/L 1,000 μg/L 30,00 μg/L 10,000 μg/L
No significant effects on plants, even at
high concentrations
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TFA and TCA
Control
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The effect of HFC and HCFCs on the biosphere
Trifluoroacetic acid (TFA)
Phytotoxic - negative effects on plant growth
But concentrations not sufficient for observed effects
Anthropogenic sources
Atmospheric degradation of some HCFC and HFCs
Atmospheric degradation of narcotics
Trifluoromethyl containing pesticides, aluminum production
Natural sources
Underwater hydrothermal vents (?)
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Approximate concentrations of TFA
•Switzerland, Fresh water lakes, springs, rivers: ca 100 ng/L
•USA, Fresh water lakes, springs, rivers: 20 – 140 ng/L
•Europe, Rain water: 0 - 1.5 µg/L
•Oceans: 10 – 200 ng/L
Depositions of TFA largest during the growing seasons
Summary
• HCFC has potential negative health effects
• TFA is not bioaccumulative
• Risks to mammals, including humans, aquatic and terrestrial organisms: negligible
• TFA sources (natural and anthropogenic) and cycling through the biosphere should be considered for their environmental impacts
• Continuing monitoring of TFA in the environment may be required if HFOs are significantly increased to replace HFCs
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Summary
WMO Assessment of Ozone Depletion (2007):
“TFA from the degradation of HCFCs and HFCs will not
result in environmental concentrations capable of
significant ecosystem damage.”
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