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Global Change:

Ozone Depletion

Environmental Sustainability Educational Resources

prepared by

Gregory A. Keoleian

Associate Research Scientist,

School of Natural Resources and Environment

Co-Director, Center for Sustainable Systems

University of Michigan

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Contents Ozone Depletion Process [slide 4]

Ozone Hole [slide 5]

Ozone Hole [slide 6]

Ozone Depleting Substances [slide 7] Ozone Depleting Substances [slide 8]

Ozone Depleting Substances [slide 9]

Ozone Depletion Potential [slide 10]

Ozone Depletion Potential [slide 11]

Impacts [slide 12]

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Montreal Protocol [slide 13] Additional Resources [slide 14]

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Ozone Depleting Substances

Chlorofluorocarbons (CFCs)

contains: Cl, F, C

long-lived, non-toxic, non-corrosive, and non-

flammable

in 1960s used in refrigerators, air conditioners,

spray cans, solvents, foamsphase out by 1996 in developed countries

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Hydrochlorofluorocarbons (HCFCs)

contains: H, Cl, F, C

first major replacement for CFC ODPs range from 0.01 - 0.1

much less destructive by also ozone depleting

reduce HCFCs by 35% by 2004 in developedcountries

Hydrofuluorocarbons (HFC)

contain: H, F, Cdo not deplete O3

some HFCs have a high GWP

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Halons

contain: Br, Cl (in some but not all), F, H (in

some but not all), CBr many times more effective in destroying O3

ODPs range up to 10

used in fire extinguishers

phase out by 1994

Methyl Bromide (CH3Br)

an effective pesticide, used to fumigate ag soil

and products

ODP = 0.4

production in US will end 12/31/2000

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Ozone Depletion Potential

Ozone Depletion Potential (ODP): a

number that refers to the amount of ozone

depletion caused by a substance

The ODP is the ratio of the impact on ozone

of a chemical compared to the impact of a

similar mass of CFC-11.

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Ozone Depletion Potential

ODP of CFC-11 is defined to be 1.0.

Other CFCs and HCFCs have ODPs that

range from 0.01 to 1.0. Halons have ODPs ranging up to 10.

Carbon tetrachloride has an ODP of 1.2

Methyl chloroform's ODP is 0.11. HFCs have zero ODP because they do not

contain chlorine.

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Impacts

Ozone layer absorbs most of the harmful

UV-B radiation; more UV-B means:

more melanoma and non-melanoma skin

cancers

more eye cataracts

weakened immune systems

reduced plant yields

damage to ocean eco-ecosystems

more damage to plastics

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Montreal Protocol Vienna Convention in 1985

framework agreement

Montreal Protocol in 1987 Phase-out schedules for CFCs and halons

London Amendment in 1990

accelerated phase outs; additional CFCs, CCl4, CH3CCl3

Copenhagen Amendment in 1992 added methyl bromide, HBFCs, HCFCs

Montreal Amendment in 1997 finalized phase-out schedules for methyl bromide

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Additional Resources

US EPA

web site: http://www.epa.gov/ozone/

NASAweb site:

http://www.nas.nasa.gov/Services/Education/

Resources/TeacherWork/Ozone/Ozone.homep

age.html