Stratospheric
Ozone Depletion
NOTE:
This is a resource module for teachers and
students interested in the ozone layer. The NASA Advanced Supercomputing
Division does not perform research directly related to the ozone
and ozone depletion. For more information and to get answers to
questions, see the following NASA websites:
NASA
Goddard Institute for Space Studies - Atmospheric Chemistry
Total Ozone Mapping Spectrometer
- ozone measurements
Stratospheric
ozone depletion is a concern because the ozone layer in the stratosphere
keeps 95-99% of the suns ultraviolet radiation from striking the earth.
In this file are:
-
Internet resources for both ozone information, and neat digitized
images of the antarctic
ozone hole.
-
Printed information including phone and e-mail contacts for
those who wish to pursue the issue of ozone depletion further.
For those in a hurry, my favorite source of quick yet reliable
answers is Frequently-asked-Questions on Ozone by Robert Parson.
For general science questions on the atmosphere the college undergrad
textbook Atmospheric Change: An Earth
System Perspective, an authoritative text accessible to those
with a high school science background.
- An
important part of the ozone discussion is the use of scientific
models in an effort to better understand the problem and
make useful predictions. I have written a laymans guide to scientific
modelling which can aid you in understanding some of the applications
and limitations of modeling.
- Some
of the controversies surrounding the science and theories
of ozone depletion are summarized here.
- Brief
glossary of some of the terms and concepts used when discussing
ozone depletion.
- A
summary of the ozone depletion issue, below, with highlighted
terms that you can click on for further information.
Stratospheric
ozone depletion is a concern because the ozone
layer in the stratosphere keeps
95-99% of the suns ultraviolet radiation
from striking the earth. A number of consequences can result from
increased levels of UV(ultraviolet radiation) striking the earth,
including: genetic damage,
eye damage and
damage to marine life. Increased UV radiation in the lower atmosphere,
called the troposphere, can result in increased amounts of photochemical
smog. Photochemical smog is already a health hazard in many of the
world's largest cities.
The decrease of stratospheric ozone was first
reported in 1974 and the decrease was quickly linked
to the increasing presence of a class of manmade compounds called
CFC's or Chlorofluorocarbons. Many countries
of the world have moved to
reduce the use of CFC's but because of the slow rate of air
mixing between the lower and upper atmosphere it is theorized that
stratospheric CFC's will stay at a significant level well into the
next century.
Stratospheric ozone depletion has become very much a controversial
political and economic issue as well as a complex scientific issue.
Major and minor sources of chlorine,
and factors which affect
ozone levels are still being sorted out among a great deal of
media-generated excitement and misinformation; but the link
between CFC's and Ozone depletion, and the major factors creating
the antarctic ozone hole, are
considered by most researchers to be well established facts. Scientific
models of the atmosphere are
being constructed in order to assist scientists in looking for other
factors in Ozone depletion, evaluate their importance and predict
what may happen to our atmosphere in the future.
**This file may be copied, distributed and archived but all copies
must include this caveat as well. Caveat: This document is a compilation
of information from a number of sources, with the gracious assistance
of NASA and the IISME program, but does not necessarily reflect
their views and definitely does not reflect the breadth of their
knowledge. I am solely responsible for what is written here, including
errors. Students should note that since this is not a peer
reviewed publication, it should not be used as a reference for science
projects; instead all scientifc facts and data should be referenced
back to the original authors.
Author: Brien Sparling. Chemistry Teacher. Live Oak High School.
Morgan Hill. California. 95037
| 
