the ozone layer - university of rio grande ozone layer environmental science nsc 23404 ... • tree...
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The Ozone Layer
Environmental ScienceNSC 23404
Sunday, March 31, 2013
thermosphere
mesospherestratosphere
Atmosphere• Layers of gases
surrounding the earth.
troposphere
Sunday, March 31, 2013
Air Pollution Review• Presence in air of any
substance having undesirable effects.
• Mainly in troposphere• Criteria (Conventional)
- PM, VOC, NOx, SO2, CO, Pb, O3
• Hazardous Air Pollutants (HAP’s) - Hg, Dioxin
Sunday, March 31, 2013
Effects of Air Pollution Summary• Respiratory Problems -
coughing, bronchitis, asthma, emphysema, cancer
• Cardiovascular Problems - CO• Nerve Damage - Hg and Pb
• Tree damage• Acidify lakes• Damage concrete, statues
Sunday, March 31, 2013
stratosphere
troposphere
Stratosphere/Ozone Layer
Sunday, March 31, 2013
Activity -Change over Years
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Sunday, March 31, 2013
Mean Ozone Hole Size
0
10
20
30
1979 1982 1986 1989 1992 1996 1999 2002 2005 2009 2012
Are
a (m
illio
ns o
f squ
are
kilo
met
ers
Area of Antarctica
Data from: http://ozonewatch.gsfc.nasa.gov/meteorology/annual_data.html
Sunday, March 31, 2013
Solar Spectrum
Sunday, March 31, 2013
UV Spectrum•UV light at top and bottom of stratosphere
•Assumes 300 Dobson Units
Sunday, March 31, 2013
Less Ozone Northern Hemisphere
Sunday, March 31, 2013
Less Ozone meansMore UV on surface
Sunday, March 31, 2013
Effects of UV
• Sunburn
• Accelerated Aging (wrinkles, sun spots)
• Depresses immune system
Sunday, March 31, 2013
Epidermis
Melanocytes (melanin)
Skin
Dermis
Basal Layer
Squamous (Flat) Cells
Sunday, March 31, 2013
More UV - More Skin Cancer
Melanoma4%
Basal Cell Cancer80%
Squamous Cell Cancer16%
Sunday, March 31, 2013
CataractsClouding of Lens of Eye
400,000 new cases/year US (1 in 49 people)
Sunday, March 31, 2013
Know Your Risk
Sunday, March 31, 2013
UV Index
Category Action
0-2 Low Sunglasses
3-5 Moderate Sunglasses,covering up, shade
6-7 High Sunglasses, 30+ sunscreen, protective clothing, reduce time in sun from 10-4
8-10 Very high Sunglasses. 30+ sunscreen, shirt, don’t stay out in sun
11+ Extreme risk
Avoid sun 10-4, long sleeve shirt and trousers. sunglasses
Sunday, March 31, 2013
Principle Cause of Ozone Depletion
C
F
Cl
Cl
Cl C
F
F
Cl
Cl
Once used in:•Air conditioners•Refrigerators•Aerosol Sprays•Plastic Foams
Chlorofluorocarbons - CFC’s
Sunday, March 31, 2013
Chemical Reactions* CFCl3 + UV ➔ Cl• + CFCl2
Cl C
F
Cl
ClOO
O
* ClO• + O• ➔ O2 + Cl•
* Cl• + O3 ➔ O2 + ClO•
Cl•
Cl-O•
Sunday, March 31, 2013
Ozone Destruction Animation
* 1 Cl• can destroy 100,000 ozone* CFC’s have a 60-100 year lifespan
http://www.theozonehole.com/ozonedestruction.htm
Sunday, March 31, 2013
Other Ozone-Destroying ChemicalsMethyl Bromide - Pesticide
Halons - Fire Extinguishers
C
H
H
H
Br
Carbon Tetrachloride & Methyl Chloroform - Solvents
C
Cl
Cl
Cl
Cl C
H
H
H
C
Cl
Cl
Cl
HCFC’s - RefrigerantsC
H
F
F
Cl
Sunday, March 31, 2013
Montreal Protocol
• 191 Nations - 1987- Montreal, Canada• 1st plan - reduce CFC production 50% by
2000• Later plan - complete phase out by 1996
Sunday, March 31, 2013
Substance MDC LDC
CFC’s 1995 2010
Halons 1993 2010
Carbon tetrachloride 1995 2010
Methyl Chloroform 1995 2015
Methyl Bromide 2005 2015
HCFC’s 2020 2040
Montreal Protocol Phase-Outs
Sunday, March 31, 2013
Length of Problem
• not all countries part of protocol• not all chemicals have been phased out yet• chemicals have 60-100 year life span
Sunday, March 31, 2013
Ozone Depletion
≠ Global Warming
Sunday, March 31, 2013