The California Collection/TheCaliforniaCollection.cdr/his081/ozone.lzh/OZONE.TXT

Text File | 1991-07-09 | 12KB | 226 lines

WAR:Refrigerants and the Atmosphere (questions & answers)  by Dean Lewis

   This information is provided as a public service by the
Refrigeration Service Engineers Society and your heating and air
conditioning service contractor. It is intended to provide clear,
factual answers to questions about stratospheric ozone depletion, what
is being done about it, and how the situation will affect you.

   Q: WHAT IS OZONE?

   Ozone is a gas. It consists of three atoms of oxygen in each
molecule; the oxygen we breathe contains two atoms in each molecule.
Chemically, oxygen is O2, and ozone is O3. The ozone layer consists of
ozone in the stratosphere, high above the earth at an altitude of
between 7 and 28 miles. It is formed by ultraviolet light from the sun
acting on oxygen molecules. The ozone layer absorbs and scatters
ultraviolet light from the sun, preventing harmful amounts of
ultraviolet from reaching the earth. For this reason, it is often
referred to as the Ozone Shield.

   Q: BUT ISN'T OZONE UNHEALTHFUL?

   Yes, when it occurs in the lower atmosphere where we breathe it.
This is caused by ultraviolet radiation from the sun acting on smog and
air pollutants on hot Summer days. This situation should not be
confused with the protective ozone layer in the stratosphere. Ozone at
ground level is a harmful pollutant; in the stratosphere it is a
protective shield.

   WHAT ARE CFCs?

   CFC stands for chlorofluorocarbon; chemicals that contain chlorine,
fluorine and carbon, and may contain hydrogen. These chemicals are
inexpensive, safe, non-flammable refrigerants of high thermal
efficiency. They are also used as solvents in cleaning electronic
microcircuits, and as the blowing agent in manufacturing foam
insulations. There are some other uses, as well. In many other
countries, CFCs are still used as aerosol propellants.

   CFC is the general term often used inaccurately for all these
compounds. It is important to realize that not all CFCs are equally
suspected of affecting the atmosphere. CFCs which contain chlorine but
no hydrogen (fully halogenated CFCs) are the real problem. Those which
contain no chlorine, only fluorine (HFCs), and those which contain
hydrogen along with chlorine (HCFCs), have a far smaller effect, if any
at all.

   Q: WHAT DO CFCs DO TO THE OZONE LAYER?

   Certain chlorine-containing refrigerants are so stable that they do
not break down in the lower atmosphere, even a hundred years or more
after being released. These chemicals gradually float up to the
stratosphere, where the chlorine reacts with ozone, causing it to
change back to oxygen. The chlorine is not used up in the reaction;
each molecule goes on to cause more and more ozone-to-oxygen reactions.

   Q: ARE THERE OTHER CHEMICALS THAT HAVE THE SAME EFFECT?

   Yes; bromine-containing compounds, such as contained in certain
Halon fire extinguishers, also have been implicated in potential ozone
depletion. Bromine is chemically related to chlorine.

   Q: WHAT IS THE RESULT?

   Depletion of the ozone layer could result in increased exposure to
ultraviolet radiation at some point in the future. The best available
scientific information indicates that proper action taken now to reduce
consumption of fully halogenated CFCs should avoid possible future
effects on humans and the environment. Potential effects include
increases in skin cancer and cataracts, inability to resist certain
infectious diseases, decreased yields of agricultural crops, and
effects on marine life that is essential to the food chain.

   Q: WHAT IS THE OZONE HOLE I'VE READ ABOUT?

   This is a thinning in the ozone layer over Antarctica, which occurs
during the Antarctic Spring season (Autumn in the Northern Hemisphere).
It occurs over the Antarctic continent due to the unique climate caused
by powerful circumpolar winds and extremely low temperatures there; the
lowest on earth. This area is being carefully monitored for the degree
to which ozone thins out, since it has been found to lead to ozone
depletion in other parts of the world, as well. Significantly reduced
ozone levels were detected in 1985, and high chlorine levels were found
in 1986. Instrumented aircraft flights through this layer indicate that
the ozone depletion problem may be more serious than initially thought.

   Q: DIDN'T WE STOP USING CFCs IN SPRAY CANS FOR THIS REASON?

   During the early 1970s, CFCs used as aerosol propellants constituted
over 50% of total CFC consumption in the U.S. Following concerns
initially raised by Professor Sherwood Rowland and Dr. Mario Molina in
1974, the E.P.A. and the Food and Drug Administration in 1978 banned
the use of CFCs as aerosol propellants in all but a few essential
applications. This use of CFCs was reduced in the U.S. by approximately
95%. Unfortunately, very few other countries followed the U.S. in this
ban. Because of the many practical uses of CFCs, their production and
use has now surpassed pre-1974 levels.

   Q: IS THIS THE SAME AS THE GREENHOUSE EFFECT?

   No, but CFCs may be involved in this problem, also. The greenhouse
effect occurs when carbon dioxide (mostly form the burning of fossil
fuels; oil, natural gas, and coal) and other gases (methane, nitrogen,
oxides, and others) build up in the atmosphere. These gases let
incoming sunlight and its heat reach the earth, but block the earth's
heat from radiating into space. This is the way a greenhouse works, and
so the name of the effect. As the gases build up, more heat is trapped,
and the planets temperature rises. Some scientists now feel that CFCs
may also be contributing to this effect.

   Q: WHAT IS BEING DONE TO STOP DEPLETION OF THE OZONE LAYER?

   Scientists from around the world recognize the importance and severe
results of this problem, and realize that all countries must cooperate
to stop erosion of the ozone shield.

   In the Fall on 1987, representative of more than 30 nations, meeting
in Montreal, Canada, signed an agreement now known as the Montreal
Protocol. The U.S. and Canada were included. On August 1, 1988, the
U.S. Environmental Protection Agency (E.P.A.) enacted the provisions of
this agreement into regulations for the United States.

   The Montreal Protocol and the E.P.A. specify that as of July 1,
1989, production and consumption of certain CFCs will be limited to the
levels produced and consumed in 1986. This actually means a cutback,
because use has grown since that time. In July, 1993, these levels will
be reduced by 20%, and to 50% of 1986 levels in July of 1998.
Specifically, the chemicals involved are the fully halogenated CFCs 11,
12, 113, 114, and 115. Halons 1211, 1301, and 2402 are also covered,
but on a different time schedule. Scientific, technological, and
economic concerns are to be reviewed at least every four years, with
the first review in 1990.

   The most recent technical information indicates that even deeper
cuts in production and use may be necessary. The head of the E.P.A. has
stated that these chemicals should be completely eliminated, and some
responsible industry trade groups agree.

   But all is not lost when it comes to our needs for refrigerants.

   It's important to remember that only fully halogenated refrigerants
are being phased down. The refrigerant in home refrigerators, freezers
and automotive air conditioning is mostly CFC 12, one of those being
regulated. But central home air conditioning typically uses HCFC 22.

   Over a period of time, new appliances can be redesigned to use HCFCs
in place of fully halogenated CFCs. Manufacturers of electronic
microcircuits uses CFCs to clean parts. They are successfully switching
to other chemicals. Manufacturers of foam insulation use CFCs to
produce the insulating bubbles in the insulation. There are other
methods and chemicals they can used, although these produce insulation
that is less efficient.

   New replacement refrigerators are also being developed, but these
will require years of testing for any toxic effects, to make sure they
are safe.

   Q: CAN'T WE JUST SWITCH TO SOME OF THE OTHER REFRIGERANTS?

   Yes, but this is going to take time. HFC and HCFC refrigerants can
replace the CFCs, but the refrigeration and air conditioning equipment
has to be redesigned and manufactured. The existing refrigerant in your
refrigerator, as an example, cannot be simply removed and replaced with
one of the other refrigerants, because the compressor, cooling coil,
and other components in the system were designed for the specific
refrigerant being used. Different refrigerants have different
characteristics, which affect the compressor and other components in
the system.

   A lubricating oil also has to be developed that will be compatible
with the new HCFCs and HFCs.

   Q: HOW WILL THIS SITUATION AFFECT US?

   As mentioned, insulation can be manufactured using other methods and
chemicals, but the result is less efficient; greater thicknesses of
insulation will have to be used to get the same insulating effect. That
will mean refrigerators and freezers that are either larger on the
outside or smaller on the inside. Refrigerated trucks can not be make
larger on the outside, of course, and so cargo capacity will be
reduced. Carrying less frozen food per trip will mean somewhat higher
transportation costs, which may increase some of the prices we pay.

   Necessary changes in the processing of frozen foods may also result
in increased costs.

   Refrigerators, freezers, and other systems using CFC-12 that are
redesigned for other refrigerants will probably be slightly less
efficient, using more electricity for operation. They may also be
somewhat heavier.

   The price your air conditioning service contractor pays for
refrigerant will increase, as a result of shorter supplies. To help
control these costs and make supplies go farther, your service
technician will take steps to conserve, recover, and re-use
refrigerants. It is increasingly important to find and repair leaks in
systems, rather than just adding more refrigerant periodically.

   Existing residential appliances and systems should not become
obsolete nor have to be replaced any sooner. Owners and operators of
large commercial air conditioners and refrigeration systems will
probably notice a great many more changes than the homeowner will.

   The more thoroughly we can prevent the escape of CFCs to the
atmosphere, and the more wisely we can conserve and recycle these
materials, the better we can protect our health and that of generations
to come, protect the environment, and control our overall costs in the
long run.

   This information was copied 12 October 1989 by

   Jerry J. Trantow Research Scientist Johnson Controls, Inc. 507 E.
Michigan Street MS-36 Milwaukee, Wi 53201

   out of a bulletin from:

   Refrigeration Service Engineers Society 1666 Rand Road Des Plaines,
Illinois 60016-3552 PHONE [phone] FAX [phone]

   with permission from Dean Lewis. if you would like an original copy
send a self-addressed stamped business size (#10) envelope to RSES
requesting a copy of "Consumers' Question and Answers, Refrigerants and
the Atmosphere". Quantities are also available, call RSES for details.
The original bulletin has several color pictures of the ozone hole,
chemical reactions, etc.