After carefully reading the EPA web site, I find major contradictions with the facts in the above writeup by BigHoliday. Note that BigHoliday mentions EPA as source!
Facts from the EPA web site (http://www.epa.gov/ozone/) about the ozone hole:
-
There was no ozone hole in 1956. The EPA site refers to the British Atlantic Survey (BAS).
See http://www.epa.gov/ozone/science/hole/holehome.html
and http://www.nbs.ac.uk/public/icd/jds/ozone/history.html
- The ozone layer DOES protect us from cancer:
Laboratory and epidemiological studies demonstrate that UVB causes nonmelanoma skin cancer and plays a major role in malignant melanoma development. In addition, UVB has been linked to cataracts. All sunlight contains some UVB, even with normal ozone levels. It is always important
to limit exposure to the sun. However, ozone depletion will increase the amount of UVB, which will then increase the risk of health effects. Furthermore, UVB harms some crops, plastics and other materials, and certain types of marine life.
Quote from http://www.epa.gov/ozone/science/sc_fact.html
- Volcanoes are not the primary cause for ozone depletion:
First, the vast majority of volcanic eruptions are too weak to reach the stratosphere, around 10 km above the surface. Thus, any HCl emitted in the eruption begins in the troposphere. Sea salt from the oceans is also released very low in the atmosphere. These compounds would have to
remain airborne for 2-5 years to be carried to the stratosphere. However, both sea salt and HCl are extremely soluble in water, as opposed to CFCs which do not dissolve in water. Rain effectively scrubs the troposphere, removing both of these forms of chlorine. Steam in volcanic plumes can act the same way, removing HCl long before it reaches the ozone layer. Measurements have shown that concentrations of these substances vanish very rapidly as altitude increases. Neither sea salt from the oceans nor tropospheric-level volcanic eruptions (like Mt. Erebus in
Antarctica) contribute significantly to stratospheric chlorine levels. Some sea life does produce methyl chloride, a more stable form of chlorine than sea salt, but its contribution is small, as explained below.
CFCs, on the other hand, do not dissolve in rain. In addition, no chemical processes have been found that aggressively remove them from the troposphere. In fact, one of the advantages of the CFCs was their stability. However, it is this very stability that poses a threat to the ozone layer.
Quote from http://www.epa.gov/ozone/science/volcano.html
All information was gathered on March 24, 2001 from:
EPA, http://www.epa.gov/ozone/science/
British Antarctic Survey Ozone, http://www.nbs.ac.uk/public/icd/jds/ozone/index.html
If you find any errors or inconsistencies in my writeup, please tell me immediately!