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Ozone good & bad. Ozone In the Atmosphere. 100. 60. Thermosphere. 80. 50. 40. Mesosphere. 60. Altitude (miles). 30. Altitude (km). 40. 90% of ozone is in the stratosphere. 20. 20. 10. 10% of ozone is in the troposphere. Troposphere. 0. 0. 0. 2. 4. 6. 8. - PowerPoint PPT Presentation
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Ozonegood & bad
2Ozone (parts per million)
0
20
40
60
80
100
Alt
itud
e (k
m)
Troposphere
Mesosphere
Thermosphere
Ozone In the AtmosphereA
ltitude (miles)
10
0
20
30
40
50
60
90% of ozone is in the stratosphere
0 2 4 6 8
10% of ozone is in the troposphere
3
UVc - 100% AbsorptionUVb - 90% Absorption
UVa - 50% Absorption & Scattering
Ozone is the Earth’s natural sunscreen
Ozone (parts per million)
0
20
40
60
80
100
Alt
itud
e (k
m)
Troposphere
Mesosphere
Thermosphere
Altitude (m
iles)
10
0
20
30
40
50
60
0 2 4 6 8
4
16%
32%
23%
12%
7%5%
1%4%
0
3400
3000
2000
1000
(CH3CCl3)
(e.g., HCFC-22 = CHClF2)
(CCl2FCClF2)
Naturalsources
Other gasesMethyl chloroform
HCFCs
CFC-113
Carbon tetrachloride (CCl4)
CFC-11 (CCl3F)
CFC-12 (CCl2F2)
Methyl chloride (CH3Cl)
0
20
15
10
5
15%
27-42%
5-20%20%
14%
4%
Methyl bromide (CH3Br)
Halon-1211 (CBrCIF 2)
Halon-1301 (CBrF3)
Other halons
Very-short lived gases (e.g., bromoform = CHBr3)
Chemicals that Destroy Stratospheric Ozone
• Cl is much more abundant than Br• Br is about 50 times more effective at O3 destruction
From Ozone FAQ - see http://www.unep.org/ozone/faq.shtml
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October Average Ozone HoleOctober Average Ozone Hole
LowOzone
HighOzone
NOx
NMVOCs
NOx
NMVOCs
CONTINENT 2 OCEAN
O3
Boundary layer
(0-2.5 km)
Free Troposphere
CONTINENT 1
Tropospheric ozone links air pollution & climate change (1) primary constituent of smog in surface air [NRC, 1991]
(2) 3rd most important greenhouse gas [IPCC, 2001]
OH HO2
VOC, CH4, CO
NONO2
hO3
O3
Hemispheric Pollution
Direct Intercontinental Transport
greenhouse gas
air pollution (smog)
air pollution (smog)
