Ozone-Depletion-global-0111-layer-deplet

globalozonelayer.

1. 1
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

2. 2
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]

3. 3
•Montreal Protocol [slide 13]
•Additional Resources [slide 14]

4. 4

5. 5

6. 6

7. 7
Ozone Depleting Substances
•Chlorofluorocarbons (CFC’s)
–contains: Cl, F, C
–long-lived, non-toxic, non-corrosive, and non-
flammable
–in 1960’s used in refrigerators, air conditioners,
spray cans, solvents, foams
–phase out by 1996 in developed countries

8. 8
•Hydrochlorofluorocarbons (HCFCs)
–contains: H, Cl, F, C
–first major replacement for CFC
•ODP’s range from 0.01 - 0.1
–much less destructive by also ozone depleting
–reduce HCFC’s by 35% by 2004 in developed countries
•Hydrofuluorocarbons (HFC)
–contain: H, F, C
–do not deplete O3
–some HFC’s have a high GWP

9. 9
•Halons
–contain: Br, Cl (in some but not all), F, H (in some but not all), C
–Br 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

10. 10
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.

11. 11
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.

12. 12
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

13. 13
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 CFC’s, CCl4, CH3CCl3
•Copenhagen Amendment in 1992
–added methyl bromide, HBFCs, HCFCs
•Montreal Amendment in 1997
–finalized phase-out schedules for methyl bromide

14. 14
Additional Resources
•US EPA
–web site: http://www.epa.gov/ozone/
•NASA
–web site:
http://www.nas.nasa.gov/Services/Education/
Resources/TeacherWork/Ozone/
Ozone.homepage.html