1. What Is Ozone? Why Should We Care about Something We Can’t See? Dr. Michael J Passow Earth2Class Introduction 19 Oct 2013

2. What is Ozone? Simply explained, ozone is a highly reactive form of oxygen molecules O 3 Ozone poses two biological problems, depending on whether it is: “Tropospheric Ozone” or “Stratospheric Ozone”

3. Tropospheric Ozone Produced mainly by reaction of sunlight, oxygen, and exhaust from combustion engines (hydrocarbons/nitrogen oxides) Major component of photochemical smog Dangerous to people with respiratory ailments Also damages plants, especially in North American and European forests

4. Stratospheric Ozone Above 11 km (7 mi) “Ozone Shield” protects against solar ultraviolet radiation Satellites have monitored significant declines over past few decades Most noticeable declines over Antarctica “Peaked” (?) in 2006

5. Measured in DOBSON UNITS Number of O 3 molecules in a vertical column of the atmosphere

6. Progress in Monitoring 1979 – 1993: NASA/NOAA Nimbus-7 1993 – 1994: Metor-3 (USSR) 1996 – 2004: NASA Earth Probe TOMS 2004 – present: OMI instrument aboard Aura (KNMI/NASA)

7. NASA Ozone Monitoring NIMBUS-7 TOMS INSTRUMENT AND SATELLITE INFORMATION http://ozoneaq.gsfc.nasa.gov/n7sat.md Other satellites and platforms (balloon sondes)

8. Nimbus 7 Satellite http://ozoneaq.gsfc.nasa.gov/displayImage.md?image=n7art.gif&alt=Nimbus-7%20Drawing

9. Ozone Hole Watch NASA provides info about O 3 maps, meteorology, facts, multimedia, and education http:// ozonewatch.gsfc.nasa.gov /

10. http://blogs.agu.org/wildwildscience/files/201 1/05/ozone_hole_large.jpg

11. http://ozonewatch.gsfc.nasa.gov/

12. 2013 Season

13. What Probably Created the Ozone Hole? Chlorofluorocarbons (CFCs) Synthetic hydrocarbons in which H is replaced by halogens (e.g., CHF 2 Cl, CFCl 3, CF 2 Cl 2 ) Also, Br compounds Widely used refrigerants and propellants In the atmosphere, may take 60 – 100 years to decompose 1987 Montreal Protocol established scheduled reduction in use

14. What Else Depletes Ozone? Nitrous Oxide (N 2 O) Like CFCs, stable in stratosphere and able to deplete O 3 Unlike CFCs, 60% derived from natural sources >decomposition of N compounds in soil and water >burning fossil fuels & plants (deforestation) >use of manure, fertilizers on crops

15. Some Dangers of N 2 O Montreal Protocol does not regulate N 2 O In troposphere, potent greenhouse gas (~300 x as potent as CO 2 ) Impact on ozone hole not definitively established, but of concern to scientists

16. Ozone Hole History ://www.theozonehole.com/ozoneholehistory. htm ://www.theozonehole.com/ozoneholehistory. htm

17. NOAA’s Ozone Page http://www.oar.noaa.gov/k12/html/ozone2.html

18. References http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/O /Ozone.html http://ozoneaq.gsfc.nasa.gov/n7sat.md http://ozonewatch.gsfc.nasa.gov/ http://blogs.agu.org/wildwildscience/files/2011/05/ozone _hole_large.jpg http://www.theozonehole.com/ozoneholehistory.htm http://www.oar.noaa.gov/k12/html/ozone2.html