BP-293E
OZONE: THE
EARTH'S SUNSCREEN
Prepared by:
Daniel Brassard
Science and Technology Division
April 1992
TABLE
OF CONTENTS
THE
NATURAL SYSTEM
A.
Ozone
B.
Ultraviolet Rays
1.
Impact on Mankind
2.
Impact on Biosphere
C.
Extent of the Damage
MAN-MADE
AGENTS
A.
Types of Agents
B.
Technological Alternatives to the Agents
ACTION
TAKEN TO REDUCE THE DESTRUCTIVE AGENTS
A.
International Action
B.
Canadian Federal-Provincial Action
C.
Federal Initiatives
D.
Action Still to be Taken
SUMMARY
AND CONCLUSION
SELECTED
REFERENCES
OZONE:
THE EARTH'S SUNSCREEN
Life on earth is a delicate
balance of many different elements. The conditions necessary for the diversity
and abundance of life are fairly restricted and any major change can have
unpredictable results. The raw energy of the sun maintains all forms of
life on the planet.
One of the main components
of the suns energy transmitted to the earth is ultraviolet radiation.
This radiation can be very useful in moderation; in excess, it can cause
serious problems to mankind and to the biosphere in general. One of the
main mechanisms that moderate this radiation is the ozone in the stratosphere.
It could be said that the ozone layer acts as the earths sunscreen.
Since the 1970s, we have
known that various man-made products are destroying this life-preserving
filter. Much has been done to attempt to improve the situation, which
has become increasingly alarming. The recent preliminary finding of the
National Aeronautics and Space Agency (NASA) suggests that the situation
is worse than had been anticipated and that Canada can expect increased
frequencies of "holes" in the ozone layer in the future. This
paper will discuss the various aspects of the ozone situation, from technical
explanations to the latest efforts to remedy the problem.
THE
NATURAL SYSTEM
The atmosphere is the earths
protective blanket that enables life to exist. Life on earth evolved slowly
so that each portion of the ecosystem is adapted to make best use of the
available conditions. Over geological time periods, the earths atmosphere
has changed. Human activity has caused many of the changes in the atmosphere
and has itself slowly had to adapt to them.
Mankind over the last century
has been changing the composition of the earths atmosphere. Some
changes, such as increasing the amount of pollution in the air we breathe
and modifying the energy absorption characteristics of the atmosphere,
will have a direct impact on mankind. The direct fouling of breathable
air is very noticeable; however, modifications to the absorption and reflective
qualities of the atmosphere are more long-term and more difficult to observe
directly, particularly given the large number of interacting elements.
Some of these changes include the reduced absorption of harmful ultraviolet
radiation, which increases the reflection of energy back into space, and
in turn the reflection of the reabsorbed heat energy, so as to trap the
energy light in much the same way as a greenhouse does.
A.
Ozone
One characteristic of the
atmosphere changed by mankind is the quantity of ozone available to protect
life on earth. To fully appreciate the importance of this, we need a basic
understanding of the processes surrounding ozone change.
Ozone (O3) is
a pungent-smelling, slightly bluish gas, which is a close chemical cousin
to molecular oxygen (O2). It can be found from ground level
up to about 60 km; the stratosphere contains approximately 90% of
all ozone. The stratospheric ozone has a peak concentration at 25 km
and forms a layer about 20 km thick which is located between 15 km
and 35 km above the earths surface. The ozone is so thin that
if it were compressed to ground-level pressure, it would form a layer
only 3 mm thick.(1)
Ozone, particularly in the
stratosphere, is the main filter that reduces the quantity of ultraviolet
radiation reaching the earths surface. The net value of other filters
for this radiation, which include some forms of atmospheric pollution
and clouds, is not well documented.
Ozone is formed in both
the troposphere and the stratosphere. In the stratosphere, the ozone concentrations
are more stable and the conditions are better known. Ozone (O3)
is constantly produced when high energy radiation, such as ultraviolet
radiation, causes oxygen molecules (O2) to split into two oxygen
atoms and then recombine with another oxygen molecule. The formation and
destruction of ozone develops new equilibrium points, depending on various
conditions. Some processes are thought to increase the level of ozone.
Increased concentrations of carbon dioxide (CO2) and methane
(CH4), both "greenhouse gases," are predicted to
increase the column content of ozone.(2)
The level of solar radiation emitted by the sun can also directly affect
ozone production.
The production of ozone
in the troposphere is much more dynamic and unpredictable. Although the
general principles are similar to those governing the production of ozone
in the stratosphere, the much more variable conditions in the troposphere
reduce the stability of the concentrations.
The process for the destruction
of stratospheric ozone is very complex and involves numerous factors.
It is well recognized that one of the primary agents responsible is chlorine.
The process has recently come to be viewed as a "heterogenous"
reaction(3) in which ice crystals
or volcanic ash are used as platforms providing a surface on which the
chemical reactions that suppress nitrogen oxides take place.(4)
Additional strong influences on the process are the air circulation and
weather patterns, particularly in the case of the ozone "holes"
observed so far. Very cold weather can accelerate the formation of nitric
acid, which plays a major role in the destruction of ozone.
The various factors involved
in the process can arise in different ways. The chlorine in the stratosphere
can originate from numerous sources, both man-made and natural. The major
man-made contributors of chlorine are chlorofluorocarbons (CFCs) and other
similar material which slowly rise, over a period of five years, into
the stratosphere, where they decompose. CFCs will remain in the atmosphere
for more than 100 years. The surface material needed for the destructive
process arises from man-made pollution, ice crystals and major volcanic
activity.
Although the destructive
process involves many variables, a simplified view of what happens with
CFCs will highlight its magnitude. CFCs break down in the stratosphere,
the ultraviolet radiation "dissolves" the "bonds"
that hold the chlorine and fluorine and carbon atoms together and liberates
chlorine. Two distinct processes take place. In one of these, the chlorine
atom (C1) reacts with ozone (O3) to form chlorine monoxide
(C1O) and molecular oxygen (O2). In the other, chlorine oxide
(C1O) combines with atomic oxygen (O) to form atomic chlorine (C1) and
molecular oxygen (O2). Typically, one chlorine atom, acting
as a catalyst, can destroy up to 100,000 ozone molecules. Any substantial
reduction in the stratospheric ozone layer would increase the quantity
of ultraviolet energy reaching the earth.
B.
Ultraviolet Rays
The sun emits a wide spectrum
of energy, whose amount varies over time and most forms of which are used
to provide heat and light to the earth. Some is in the form of ultraviolet
energy, which has a wavelength shorter than violet light. Unfortunately,
the portion of the ultraviolet light with wavelengths from 280 to 320
nanometres, known as ultraviolet B (UV-B), is dangerous in excess.
The harmful effects of an
overabundance of UV-B fall on life directly, as well as indirectly by
damaging the biosphere and modifying the atmosphere. The extent of the
harm and the range of life forms affected are under investigation. Although
some research is showing that limited adaptation is possible, most of
the effects remain very negative. Most of the latest information on the
impact of increased UV-B is from a recent United Nations Report, Environmental
Effects of Ozone Depletion: 1991 Update,(5)
which was released to the public only in February 1992. A large portion
of the detailed material on the adverse effects of UV-B is extracted from
this report.
1.
Impact on Mankind
Human health, human cultivated
food production and man-made materials are harmed by higher levels of
UV-B. Most of the effects of excessive UV-B due to a reduction in the
ozone layer have some degree of proportionality. The large number of complex
interactions that occur can make it difficult to interpret the results.
Several direct consequences
of increased levels of UV-B on humans have been confirmed:
The induction of immunosuppression
by UV-B has been demonstrated in humans, for both light and deeply pigmented
individuals
possible increases in the incidence or severity of
infectious diseases
An increased number of
adverse ocular effects. These include age-related nearsightedness, deformation
of the lens capsule, and nuclear cataracts (a form of cataracts which
previous information excluded from consideration)
a sustained
10% decrease in ozone will be associated with between 1.6 and 1.75 million
additional cases of cataracts per year worldwide.(6)
Other medical effects are
still the subject of debate.
It is now predicted that
a sustained 10% decrease in ozone will be associated with a 26% increase
in non-melanoma skin cancer. All other things remaining constant, this
would mean an increase in excess of 300,000 cases per year worldwide.(7)
This widely publicized prediction
can be questioned in view of other studies. A review on "Cutaneous
Melanoma," published in 1991 by an epidemiologist from Boston University
cited numerous studies indicating that skin cancer appeared relatively
rarely in people with outdoor occupations.(8)
The review also cited studies supporting the hypothesis that the risk
of melanoma depends particularly on intermittent exposure to the sun,
especially in early life.(9)
Some crops show decreased
production as a result of more elevated amounts of UV-B. Experiments have
shown that a 1% reduction in the ozone layer results in a 1% reduction
in the yield of soybeans.(10)
Many crops are unaffected or show a high degree of tolerance, however.
Some research indicates that the growth and photosynthesis of certain
plants (e.g., seedlings of rye, maize and sunflower) can be inhibited
even under ambient levels of UV-B.(11)
Some materials used by mankind
degrade more quickly with increased UV-B exposure. Many classes of materials
may be susceptible and additional research is ongoing.
UV-B radiation is particularly
effective in light-induced degradation of wood and plastic products,
leads to discolouration and loss of strength. Increased UV-B will lead
to more rapid degradation
(12)
2.
Impact on Biosphere
All areas of the biosphere
appear to be affected to some extent, but some areas more so than others.
In fact, some of the consequences, if left unchecked, could be disastrous.
Marine phytoplankton, a
one-celled plant, produces at least as much biomass as all terrestrial
ecosystems combined. It is an essential ingredient in the food chain,
as well as being a major oxygen producer and a carbon sink. Recent studies
show that the aquatic ecosystem is already under UV-B stress and there
is concern that an increase in UV-B radiation will have more detrimental
effects.(13) Changes to
the quantity of phytoplankton could augment the greenhouse effect.
Many larvae, including those
of crabs, shrimp and anchovies, would be directly affected because they
spend critical periods near the surface of the water, where UV-B can penetrate.
Any reduction of the fish population could have an adverse impact on mankind.
Fish account for 18% of the animal protein in the world and 40% of the
protein consumed in Asia.(14)
Both natural vegetation
and wildlife are affected. Wildlife, particularly those species that are
active during the day, have some of the same problems as human beings.
Since the sensitivity of trees and other plant species varies, the diversity
and distribution of such species could likely change,(15)
or the species could even disappear.(16)
Unfortunately, the extent/magnitude of the impact of increased UV-B radiation
on vegetation is difficult to determine.
Environmental factors,
biotic (e.g., plant diseases and competition with other plants) and
abiotic (e.g., carbon dioxide, temperature, heavy metals and availability
of water), can interact with UV-B radiation in plants. This makes it
difficult to make quantitative predictions.(17)
Increases to the level of
UV-B also affect microorganisms. A UV-B-induced decrease in microorganisms
fixing atmospheric nitrogen would require significant substitution by
artificial fertilizer, for example in rice production.(18)
In addition, UV-B is a standard laboratory method of causing mutations
of microorganisms. Higher natural levels of UV-B could increase the possibility
of more rapid mutations, and thus more rapid adaptation to UV-B stress.
Many changes could also
come to the earths atmosphere as a result of a change in the amount
of UV-B transmitted through it. The recent UN report on the environmental
effects of ozone depletion noted several potential changes related to
the air quality in the troposphere.
Chemical reactivity in
the troposphere is expected to increase in response to increased UV-B.
Tropospheric ozone concentrations
could rise in moderate to heavily polluted areas, but should decrease
in unpolluted regions (with low oxides of nitrogen levels), as recently
confirmed by measurements in the Antarctic.
Other potentially harmful
substances (hydrogen peroxide, acids and aerosols) are expected to increase
in all regions of the troposphere due to the enhanced chemical reactivity.(19)
Another potential long-term
effect would be the increased level of carbon dioxide in the atmosphere.
The general stunting of vegetation and the reduction in marine phytoplankton
would reduce the amount of carbon dioxide removed from the atmosphere
and might accelerate global warming.(20)
C.
Extent of the Damage
There has been a great deal
of publicity about the destruction associated with the depletion of the
stratospheric ozone layer. Many of the figures shown to the general public
reflect possible impacts of relatively large reductions of the ozone layer.
Other factors that may partially offset the reduced ozone levels are rarely
discussed. Overall, the current situation is frequently portrayed in the
worst possible light, while in fact it is less threatening.
Canadians were unduly alarmed
in early 1992 by NASAs preliminary results of the chlorine levels
in the atmosphere over the Arctic. These findings, based on NASAs
ER-2 flight of 15 January 1992, showed a chlorine rate of 1.5 parts
per billion. This high level of chlorine led to a strong concern that
Canada might have had its first "ozone hole," with reductions
in the 30% to 40% range, in the spring of 1992. If this had happened in
the northern hemisphere, the hole would have approached the 50% range
recorded for the well-known Antarctic hole. Later information indicated
that the concentration of chlorine was only 0.5 parts per billion, a finding
that made unlikely the formation of a "hole" in the spring of
1992. The favourable weather conditions may have helped reduce the impact
of ozone depletion, since it is known that extreme cold can accelerate
the process of destruction. The actual ozone figures extracted from the
Ozone Watch for 11 March 1992 showed that the ozone layer
over Western Canada was 15% less than that recorded during 1960-1980,
while for the remainder of Canada it was about 5% less.(21)
Several factors can offset
the increased chlorine levels found in the stratosphere or the reduced
level of stratospheric ozone. Increased atmospheric concentrations of
CFCs and N2O are predicted to decrease the column content of
ozone, whereas increased concentrations of CO2 and CH4
are predicted to increase it. Therefore, it can be seen that the effects
of increasing concentrations of CFCs and N2O are to some degree
offset by increasing concentrations of CO2 and CH4.(22)
Both the tropospheric ozone and aerosols may be masking the consequences
of stratospheric ozone depletion by filtering out UV-B in some industrialized
regions.(23) Clouds are
also thought to filter out UV-B, but no reliable estimates of the direction
or magnitude of their effects on UV-B have been determined.(24)
Many other factors can also
influence the level of ozone. These range from volcanic activity, which
dumps gases and aerosols in the atmosphere, to the variable and cyclic
output of the sun. Major weather patterns can also be extremely important
since they can distribute the ozone more evenly.
To help place the current
extent of the problem in perspective, some more recently learned facts
are listed below:
-
Larger global
ozone decreases have been observed in winter, spring and summer at
both high and middle latitudes (3.5% reduction in summer at 45 N).(25)
For North America, this represents a summertime depletion for latitudes
between central Canada and Florida that would be about 2.9% to 3.3%.(26)
Research is underway to
assess the overall annual effect.
MAN-MADE
AGENTS
A.
Types of Agents
While we can do little to
stop volcanic action or to change weather patterns, we can reduce man-made
products that are helping to destroy the ozone layer.
Concern about the ozone
layer first surfaced in the 1970s. In the mid-1970s, attention shifted
from advanced aircraft to the ordinary aerosol spray can as the primary
cause of the ozone depletion. The group of industrial chemicals known
as CFCs were then used as propellant; thousands of tonnes of CFCs were
being released directly into the lower atmosphere where they began their
gradual drift upward to destroy the stratospheric ozone. Since then, the
list of materials known to destroy the stratospheric ozone has greatly
expanded, although CFCs remain the primary problem.
CFCs, and the other ozone-destroying
agents, are ubiquitous in almost every society. They are used in a wide
range of products that are frequently not recognized as containing ozone-destroying
materials. Because of the range of materials involved, the term "ozone-depleting
potential" (ODP) was adopted to indicate the ozone-depletion potential
of a substance, on a mass-per-kilogram basis, as compared to chlorofluorocarbon-11
(CFC-11). Such a factor is based upon the substances atmospheric
lifetime, the molecular weight of bromine and chlorine, the substances
ability to be photolytically disassociated, and upon other factors determined
to be an accurate measurement of the relative ozone-depletion potential.
Table 1 lists most
ozone-destroying agents with their ODPs, as well as some new replacements
for CFCs. The hydrochlorofluorocarbons (HCFCs) have a low ODP, while the
hydrofluorocarbons (HFCs) have a zero ODP. Both these alternatives to
CFCs are "greenhouse gases." This table also shows how ongoing
research has caused some of the ODP values to change over time. The biggest
change was in Halon H-1301, whose ODP increased from 10 to 16.
Table 1
|
ODP
|
Species
|
1991
Assessment1
|
1989
Assessment
|
Montreal
Protocol
|
CFCs
CFC-11
CFC-12
CFC-113
CFC-114
CFC-115
CCl4
1,1,1-trichlorethane
HCFCs and HFCs
HCFC-22
HCFC-123
HCFC-124
HFC-125
HFC-134a
HCFC-141b
HCFC-142b
HFC-143a
HFC-152a
HCFC-225CA
HCFC-225CB
CH3Br
Halons2
H-1301
H-1211
H-1202
H-2402
H-1201
H-2401
H-2311
|
1.0
1.0
1.07
0.8
0.5
1.08
0.12
0.055
0.02
0.022
0
0
0.11
0.065
0
0
0.025
0.033
0.6
16
4
1.25
7
1.4
0.025
0.14
|
1.0
0.9 - 1.0
0.8 - 0.9
0.6 - 0.8
0.3 - 0.5
1.0 - 1.2
0.1 - 0.16
0.04 - 0.06
0.013 - 0.022
0.016 - 0.024
0
0
0.07 - 0.11
0.05 - 0.06
0
0
-
-
|
1.0
1.0
0.8
1.0
0.6
10.0
3.0
|
1
These values are based on a new semi-empirical, observation-based method
of calculating ODPs, which has better quantified the role of polar processes
in this index.
2
These values are more uncertain than those for the chlorine-containing
chemicals.
Source: Extracted
from the Synthesis of the Reports of the Ozone Scientific Assessment Panel,
Environmental Effects Assessment Panel, Technology and Economic Assessment
Panel, Prepared by the Assessment Chairs for the Parties to the Montreal
Protocol, November 1991, p. 4.
Each of the main groups
of agents has different primary applications. Quantitatively, CFCs are
the main ozone-destroying agents. Because of their stable, non-toxic,
non-flammable and non-corrosive characteristics, they are used for a variety
of purposes and particularly in refrigeration, in the production of foams,
in aerosols and in solvents.
The other major group of
ozone-destroying agents are the halons. Halons are used as fair-fighting
chemicals for numerous reasons, including their low toxicity, unobstructed
visibility during discharge, low corrosive or abrasive residue, and high
effectiveness per pound. Since halons are normally used in closed systems,
their major discharge into the atmosphere is during training and systems
maintenance tests. Overall, their use is very restricted.
The remaining agents, such
as carbon tetrachloride (CCl4), are used in several ways, for
example, as feedstock to produce CFCs, in pesticides and in dry cleaning
agents.
Canadas contribution
to global ozone depletion is less than 2%, but its usage pattern is similar
to that of many developed nations. Figures 1 and 2 list the percentage
usage of CFCs in Canada in 1986 and 1990 respectively. The actual usage
was much lower in 1990, 13,700 versus 20,700 tonnes, and this downward
trend is continuing. A comparison of the figures also highlights the great
increase in the proportion of the usage associated with refrigeration,
up to 50% from 33%. Vast amounts of CFCs are also currently held in refrigeration
and air conditioning units.
B.
Technological Alternatives to the Agents
The need to reduce the use
of ozone-destroying agents has stimulated many technological innovations
and use of alternative materials for each major use. The largest and most
difficult changes have taken place in refrigeration and air conditioning.
In this area and with the halons used for fire protection, the urgent
need for change has made recovery, emission reductions and recycling indispensable.
In addition to major improvements
to recycling and emission, most of the developments for refrigeration
and air conditioning have been aimed at finding alternatives to CFC as
a refrigerant. Many of these to date have been based on HCFCs and to some
extent on HFCs. The first use of HFC-134a in automobile air conditioners
was in 1991, but its use is quickly expanding. One of the problems associated
with the use of HCFCs and HFCs is that they reduce energy efficiency.
Figure 1
Percentage Use of CFCs in Canada in 1986
(1) Includes aerosols
sectors.
Source: Environment
Canada.
Figure 2
Percentage Use of CFCs in Canada in 1990
(1) Includes aerosols
sectors.
Source: Environment Canada.
The most exciting advance
towards resolving the refrigeration and air conditioning problems is the
development of the thermoacoustic refrigerator, which has no moving parts
and uses environmentally benign gases. While the principle on which it
works is simple, the actual design is complex. A loudspeaker at the end
of a tube produces an extremely loud note that resonates inside a gas-filled
tube. This generates a "standing wave," which effectively transmits
the heat from its thinner region towards its thickest bulge, called the
antinode.(32) Other possibilities
are being tested.
The production of foams
for uses ranging from insulation to foam cups remains a major use of CFCs.
The primary solutions to date have been to lessen the amount of CFCs required
or to replace the CFCs with less damaging HCFCs. A new and innovative
technique, which uses oxygen and carbon dioxide as a foaming agent, has
been developed by the Lily Cup Inc. of Toronto after many years of research.(33)
Hydrocarbons have been generally
used to replace CFCs in aerosols. A new dispenser that does not use a
spray has been developed for asthma users by the Astra Pharma Inc. of
Mississauga.(34)
One of the principal users
of CFC-based solvents was the electronics industry. For most applications,
new solvents that do not use CFCs have been developed. One of these is
a water-based cleaner containing common citric acid. In 1991, Northern
Telecom developed and implemented an alternative technology for soldering
electronic circuit boards without using any solvents.(35)
Several alternative methods
are being investigated to replace halon in fire protection. Until major
developments take place, effective halon management can satisfy halon
needs for decades.
ACTION
TAKEN TO REDUCE THE DESTRUCTIVE AGENTS
A.
International Action
The international community
has taken up the challenge of halting the destruction of the stratospheric
ozone layer. This firm determination was one of the main reasons for the
rapid technological development of alternatives to CFCs. Canada, a very
active participant in international discussions, has taken action. In
March 1980, this country prohibited the use of CFCs in most common consumer
aerosols, such as hairsprays, deodorants and antiperspirants. Canada was
the first nation of the 22 countries to ratify the Vienna Convention for
the Protection of the Ozone Layer in June 1986. Since this first major
international agreement, more comprehensive initiatives to save the stratospheric
ozone layer have been agreed to.
These international agreements
are then translated into national objectives. In Canada, the federal government
has been working very co-operatively with the provinces to implement the
necessary changes. Industry has also become increasingly involved. Generally,
the aim has been to recycle, replace and reduce or destroy the main ozone-destroying
agents.
In an unprecedented demonstration
of global cooperation, the worlds nations committed themselves in
1987 to stringent action to protect the ozone layer. Their major agreement,
known as the Montreal Protocol, was designed to reduce and eventually
eliminate the use of CFCs. It was signed 16 September 1987 and came
into effect 1 January 1989.
Even as the Montreal Protocol
was being signed, it was recognized that it needed major improvements;
these were effected at the London conference in 1990. The Protocols
list of controlled substance was expanded to include methyl chloroform
and carbon tetrachloride. The amendment included the provision of a fund
to assist developing nations. At this conference, 13 countries, including
Canada, committed themselves to the elimination of CFCs by 1997, three
years ahead of the international target.
A $240-million fund headquartered
in Canada will assist developing nations to switch to more ozone-friendly
substances and technology by providing financial assistance, training
and technological information. Some of the countries, including Canada,
which has a $15-million commitment over three years, have paid their scheduled
amounts to the fund; however, as of March 1992, many nations, including
both France and the United Kingdom, had not yet done so.
The protocol appears to
be having the desired effect. Worldwide CFC consumption is now 40% below
1986 levels. At this rate, the objective of 50% reduction will be reached
during 1992, three years ahead of the amended Protocol.(36)
Since the London amendment
to the Montreal Protocol was signed in 1990, many new developments have
been announced to accelerate the phase-out of CFCs. These announcements
have been made by many of the major industrial nations and by some of
the major CFC-related industries.
The U.S. has announced that
it will phase out the production of CFCs and most ozone-depleting substances
by 31 December 1995, rather than by the year 2000. Japan is working
on a plan to accelerate the phasing-out of CFCs. Germany, Denmark and
the Netherlands are committed to phasing out CFCs by January 1995 and
the remainder of the European Economic Community (EEC) will be considering
similar action.
Canada has announced that
it will phase out CFCs by 31 December 1995 rather than the previously
announced 1997. Non-recoverable HCFCs will be phased out by 2010 and all
production and importation of HCFCs will be ended by 2020.
Industry is also responding
to the need for change. DuPont, the worlds largest producer of CFCs,
will halt its production by 1997, three years earlier than originally
planned. Large electronic manufacturers, such as Matsushita, NEC and Sony,
all have programs to eliminate the use of CFCs by 1995. As stated earlier
in this paper, Northern Telecom has developed a soldering technique that
does not need any cleaning solvents.
B.
Canadian Federal-Provincial Action
The fulfilment of Canadas
international commitments requires governments at all levels to cooperate
in making the necessary changes to reduce and eliminate ozone-damaging
agents. The Canadian Council of Ministers of the Environment (CCME) directed
in April 1989 that the Federal-Provincial Action Committee (FPAC) of the
Canadian Environmental Protection Act coordinate the development
of controls across all jurisdictions. The CCME has taken the lead in organizing
multi-jurisdictional participation in the reduction, recovery and recycling
of CFCs. On 21 August 1990, the CCME established a working group
to develop a National Action Plan for reduction, recovery and recycling.
The draft National Action
Plan is to be presented formally to the CCME in May 1992. The rapid development
of such a major plan demonstrates the level of cooperation between the
various governments on this important environmental issue. This plan identifies
six major tasks:
-
To mandate,
under provincial regulations, the recovery, recycling and reclamation
of CFCs and HCFCs from all refrigeration and air conditioning uses.
This includes banning the deliberate release of CFCs and HCFCs into
the atmosphere.
-
The development,
in conjunction with industry trade associations, of training programs
in recovery and recycling for the service sector. The training would
include the Federal Code of Practice for Emission Reduction of CFCs,
as well as hands-on equipment training.
-
To characterize
the existing bank of CFCs in Canada. This will be necessary to measure
the effectiveness of recovery/recycling activities and to plan for
ultimate destruction scenarios.
-
The development,
with the involvement of industry and standards associations, of appropriate
standards for the quality of recycled refrigerant and for the performance
of recovery equipment.
-
To ensure
that the general public is informed of the problem and the solutions.
The publics reaction and participation is an integral part of
resolving the problem.
-
To revise
government purchasing/procurement standards, including service contracts,
to ensure recovery and recycling of CFCs, HCFCs and halons.
Some governments have already
started implementing certain aspects of the draft National Action Plan.
The recovery and recycling of CFCs for automobile air conditioning during
servicing or before vehicle disposal is mandatory in Nova Scotia and Ontario.
Similar legislation is expected to be in place in all provinces by the
end of 1992.
C.
Federal Initiatives
In addition to the work
being done directly in collaboration with the provinces, the federal government
is also working on other initiatives.
On 25 August 1991,
the Environment Minister announced that $25 million in Green Plan
funding would be used to strengthen Canadas fight against ozone
layer depletion. Of these funds, $9.2 million is to step up the phase-out
of ozone-depleting substances (support for controls, regulations, recycling
and recovery). The balance of $15.8 million is to be administered
by the Atmospheric Environment Service for research, monitoring, ozone
impact prediction, and a UV-B warning system.
To permit Canadians to take
suitable precautions against increased UV-B levels, Environment Canada
announced a new advisory service shortly after NASA had confirmed the
strong possibility of a substantial reduction of the ozone layer over
a large area of Canada. The service commenced 13 March 1992, much
sooner than originally planned, and provides daily information on guarding
against exposure to the sun in view of changing UV-B levels. A similar
service has been in operation in Australia for several years.
D.
Action Still to be Taken
The developed nations have
taken aim at reducing their sources of ozone-damaging agents. Major practical
problems have yet to be overcome with respect to the vast depots of equipment
and materials containing CFCs and the aspirations of developing nations.
Developed nations have been
using CFCs since these were invented over 50 years ago. Much of the
foam and insulation containing CFCs are in refuse piles and the liberation
of their CFCs is uncertain. In addition, the world has a billion refrigeration
and air conditioning units, many of which are either poorly maintained
and leaking CFCs, and which, when they are no longer serviceable, are
simply thrown into junkyards, where the CFCs will eventually escape. No
international agreement is in place to ensure that these vast quantities
of CFCs will not find their way into the atmosphere. In the longer term,
as CFCs are no longer required for recycling, new technologies will be
required to destroy them effectively and economically.
Both eastern Europe and
large nations in Asia such as China and India have problems dealing with
ozone-related issues, especially as their ability to change to more sophisticated
technologies is relatively limited. Although India and China currently
contribute only 3% of the worlds ozone-depleting chemicals, potential
growth is enormous. China alone currently produces over eight million
refrigerators annually.
The $240-million fund established
to assist developing nations can provide only a minimum of help, considering
the scale of the problem. Canada and other developed nations must have
something tangible to offer developing nations, particularly established
recovery/recycling mechanisms and economical alternatives to CFCs. Negotiation
of "global bargains" will be essential to ensure a truly global
solution. Until "global bargains" have been struck, developed
nations could consider linking trade development programs and foreign
aid policies to the phase-out of CFCs.
Even with all the reduction
and changes that mankind is now bringing to the production of CFCs, the
ozone level will not return to normal for up to 100 years. Even if
the control measures of the amended Montreal Protocol (London, 1990) were
to be fully implemented, the stratospheric chlorine would peak at about
4.1 parts per billion by the year 2000, resulting in a reduction
in ozone of 10% in winter and 5-10% in summer.(37)
With this likely long-term
reduction in the level of ozone, humanity must adapt to the changing conditions.
We can do many things to reduce health risks such as applying a sunscreen
with a sun protection factor of at least 15. In New Zealand, school children
are urged to wear hats and to eat their lunches in the shade. Wearing
high-quality sunglasses treated to absorb UV radiation when outdoors in
bright sunlight can effectively protect the eyes. With proper precautions,
the negative health effects of ozone reduction can be minimized.
SUMMARY
AND CONCLUSION
Life on earth remains a
delicate balance of many different elements. Mankinds use of CFCs
has seriously depleted the ozone layer, which in many respects acts as
the earths sunscreen. This depletion of the stratospheric ozone
has allowed the harmful effects of increased UV-B to worsen so that the
UV-B-related destruction is likely to increase until at least the year
2000.
The international community
has cooperated as never before to remedy this situation. The reduction,
recycling and replacement of ozone-destroying agents is progressing. New
technologies and replacements are being developed so that ozone-depleting
agents can be eliminated. Since 1986, the global usage of CFCs has been
reduced by over 40%. Current projections indicate that, in the best case
scenario, the ozone layer will be at its worst in about the year 2000
and that it will take many years for it to return to its previous level.
Humanity will need to make some changes to adapt to the increased levels
of UV-B in order to minimize health problems. It is to be hoped that other
life forms on the planet can also successfully adapt to higher amounts
of UV-B.
Even with full international
cooperation, some important issues need to be addressed. How can the existing
holdings of CFCs be adequately controlled? How will the developing countries,
with their many conflicting requirements, transform themselves into ozone-friendly
nations? Until all these issues are resolved, the long-term success of
restoring the ozone layer remains clouded.
SELECTED
REFERENCES
Anderson, Stephen O. "Halon
and Stratospheric Ozone Issue." Fire Journal, Vol. 81,
No. 3, May-June 1987.
"Closing in on Arctic
Ozone." New Scientist, 9 November 1991.
"Code of Practice for
the Reduction of CFC Emission from Refrigeration and Air Conditioning
Systems." Canadian Environmental Protection Act, March 1991.
Deadly Releases of CFC.
HCSC on Environment. Report. June 1990.
Environment Canada. Ozone
Layer Protection. March 1988.
Environmental Effects
of Ozone Depletion: 1991 Update.
UN Environment Programme (UNEP), November 1991.
Milko, Robert. Ozone
Depletion and the Montreal Protocol. Library of Parliament, 28 September
1997.
"The Stratospheric
Ozone Layer over the U.S. Has Been Found Thinner in Summer." Environmental
Science Technology, Vol. 26, No. 1, 1992.
Synthesis of the Reports
of the Ozone Scientific Assessment Panel, Environmental Effects Assessment
Panel, Technology and Economic Assessment Panel, Prepared by the Assessment
Chairs for the Parties to the Montreal Protocol, November 1991.
"Volcanic Dust Threatens
the Ozone Layer." New Scientist, 7 September 1991.
Watson, Robert. Present
State of Knowledge of the Ozone Layer. NASA, June 1988.
(1)
Environment Canada, Ozone Layer Protection, March 1988, p. 5.
(2)
Robert Watson, Present State of Knowledge of the Ozone Layer, NASA,
June 1988, p. 3.
(3)
A "heterogenous" reaction is a reaction involving both gases
and solid particles.
(4)
"Volcanic Dust Threatens the Ozone Layer," New Scientist,
7 September 1991, p. 27.
(5)
Environmental Effects of Ozone Depletion: 1991 Update, UN Environment
Programme (UNEP), November 1991.
(6)
Ibid.
(7)
Ibid.
(8)
Dr. Howard Koh, New England Journal of Medicine, Vol. 325,
No. 3, 18 July 1991, p. 171.
(9)
Ibid.
(10)
Environment Canada Fact Sheet, p. 1.
(11)
Environmental Effects of Ozone Depletion: 1991 Update (1991), p. iii.
(12)
Ibid., p. iv.
(13)
Ibid.
(14)
Stephen O. Anderson, "Halons and the Stratospheric Ozone Issue,"
Fire Journal, Vol. 8, No. 3, May-June 1987.
(15)
Environmental Effects of Ozone Depletion: 1991 Update (1991), p. iv.
(16)
Synthesis of the Reports of the Ozone Scientific Assessment Panel, Environmental
Effects Assessment Panel, Technology and Economic Assessment Panel, Prepared
by the Assessment Chairs for the Parties to the Montreal Protocol, November
1991, p. 6.
(17)
Environmental Effects of Ozone Depletion: 1991 Update (1991), p. iii.
(18)
Ibid., p. iv.
(19)
Ibid.
(20)
Synthesis of the Assessment Reports
(1991), p. 6.
(21)
Environment Canada, Ozone Watch, 11 March 1992.
(22)
Watson (1988), p. 3.
(23)
Environmental Effects of Ozone Depletion: 1991 Update (1991), p. iii.
(24)
Ibid.
(25)
Synthesis of the Assessment Reports
(1991), p. 3.
(26)
"The Stratospheric Ozone Layer Over the U.S. Has Been Found Thinner
in Summer," Environmental Science Technology, Vol. 26,
No. 1, 1992.
(27)
Report, Ozone Scientific Assessment Panel, 1991, p. 3.
(28)
Ibid.
(29)
Ibid.
(30)
"The Stratospheric Ozone Layer
" (1992).
(31)
Ibid.
(32)
"Cooling with Sound: An Effort to Save Ozone Shield," New
York Times, 25 February 1992.
(33)
William Murray, "New Technology Developments as a Result of CFC Phase-Out,"
Prepared for the House of Commons Standing Committee on Environment, Library
of Parliament, 1 April 1992, p. 2.
(34)
Ibid.
(35)
"No More Ozone-Depleting Solvents," Toronto Star, 16 December
1991.
(36)
Synthesis of the Assessment Reports
(1991), p. 7.
(37)
Ibid., p. 5.
|