31-05-2013, 12:58 PM
Ozone Depletion
Ozone Depletion.ppt (Size: 816 KB / Downloads: 26)
Evolution of the Ozone Layer
Early planet history:
no ozone present
UV light directly hit planet’s surface
Oceans provided only refuge from UV radiation
Effectiveness
Other fumigants do not work
Worker health issue
Lower yields
Loss of nurseries
Even organic farms get plant stocks from nurseries that rely on methyl bromide
Hydrogen chemistry
Hydrogen is light—rises rapidly to stratosphere
Reacts with oxygen to form water
A “wetter” atmosphere would cool the lower stratosphere, especially around Poles
Increase in water vapor is catalyst for ozone depletion by freeing Cl free radicals
Ozone Depletion.ppt (Size: 816 KB / Downloads: 26)
Evolution of the Ozone Layer
Early planet history:
no ozone present
UV light directly hit planet’s surface
Oceans provided only refuge from UV radiation
Effectiveness
Other fumigants do not work
Worker health issue
Lower yields
Loss of nurseries
Even organic farms get plant stocks from nurseries that rely on methyl bromide
Hydrogen chemistry
Hydrogen is light—rises rapidly to stratosphere
Reacts with oxygen to form water
A “wetter” atmosphere would cool the lower stratosphere, especially around Poles
Increase in water vapor is catalyst for ozone depletion by freeing Cl free radicals