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Ozone is made of three oxygen atoms - O 3. Ozone. OZONE – A Greenhouse gas. Greenhouse gas. Near ground it is a nasty pollution In the stratosphere it protects us from UV radiation. Tropospheric ozone. Tropospheric ozone results from photochemical reaction involving air pollution. Toxic
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OZONE – A Greenhouse gas • Greenhouse gas. • Near ground it is a nasty pollution • In the stratosphere it protects us from UV radiation
Tropospheric ozone • Tropospheric ozone results from photochemical reaction involving air pollution. • Toxic • Greenhouse gas • Ozone in the troposphere is an anthropogenic ozone. • Responsible for positive forcing ~ 0.35 W/m2
The Stratospheric Ozone Layer • Stratosphere ozone is formed naturally from the action of solar UV radiation on atmospheric oxygen • The lower stratosphere is the location of most atmospheric ozone.
Solar UV Radiation • UV Radiation is blocked by the ozone layer • UV Radiation also forms the ozone layer.
Ozone depletion – Ozone Hole • The ozone "hole" is really a reduction in concentrations of ozone in the stratosphere.
How does Chlorine get into the Stratosphere? • chlorofluorocarbons (CFCs). • CFC-12 (CF2Cl2) (freon) • CFC-11 (CFCl3) • Have 100 year atmospheric lifetimes
Health and Environmental Effects • Skin Cancer. • Premature aging of the skin and other skin • problems • Cataracts and other eye damage • Immune system suppression Immune system damage • Damage to the DNA in various life-forms.
The Montreal Protocol • International treaty for the control on the production and consumption of ozone-depleting substances. • It was agreed on in 1987. • President Regan signed in 1988. • Globally emission of ODPs has been drastically reduced to around 10% of original levels.
EPA – Ozone Depletion ProgramUnder Clean Air Act (CAA), EPA is responsible for programs that protect the stratospheric ozone layer • Command and Control Strategy • Halt the production of ozone-depleting substances (ODS). • Ensure refrigerants and halon fire extinguishing agents are recycled properly. • identifying alternative to ODS. • banning the release of OD refrigerants. • handling of ODS, the evaluation of substitutes, and efforts to educate the public.
Will take 50 years to Recover The latest estimates are that as long as production and release of CFC's is regulated properly, global ozone levels should recover by 2050.