Repairing The Ozone Layer
REPAIRING THE OZONE LAYER
Scientists have found "holes" in the ozone layer high above the Earth. The 1990 Clean Air Act has provisions for fixing the
holes, but repairs will take a long time.
Ozone in the stratosphere, a layer of the atmosphere nine to 31 miles above the Earth, serves as a protective shield, filtering
out harmful sun rays, including a type of sunlight called ultraviolet B. Exposure to ultraviolet B has been linked to
development of cataracts (eye damage) and skin cancer.
In the mid-1970s, scientists suggested that chlorofluorocarbons (CFCs) could destroy stratospheric ozone. CFCs were
widely used then as aerosol propellants in consumer products such as hair sprays and deodorants, and for may uses in
industry. Because of concern about the possible effects of CFCs on the ozone layer, in 1978 the U.S. government banned
CFCs as propellants in aerosol cans.
Since the aerosol ban, scientists have been measuring the ozone layer. A few years ago, and ozone hole was found above
Antarctica, including the area of the South Pole. This hole, which has been appearing each year during the Antarctic winter
(our summer), is bigger than the continental United States. More recently, ozone thinning has been found in the stratosphere
above the northern half of the United States; the hole extends over Canada and up into the Arctic regions (the area of the
North Pole). The hole was first found only in winter and spring, but more recently has continued into summer. Between 1978
and 1991, there was a 4-5 percent loss of ozone in the stratosphere over the United States; this is a significant loss of ozone.
Ozone holes have also been found over northern Europe.
What could a thinned-out ozone layer do to people's lives? There could be more skin cancers and cataracts. Scientists are
looking into possible harm to agriculture, and there is already some evidence of damage to plant life in Antarctic seas.
Evidence that the ozone layer is dwindling let 93 nations, including the major industrialized nations, to agree to cooperate in
reducing production and use of chemicals that destroy the ozone layer. As it became clear the ozone layer was thinning even
more quickly than first thought, the agreement was revised to speed up the phase-out of ozone-destroying chemicals.
Unfortunately, it will be a long time before we see the ozone layer repaired. Because of the ozone-destroying chemicals
already in the stratosphere and those that will arrive within the next few years, ozone destruction will likely continue for
another twenty years.
The 1990 Clean Air Act sets a schedule for ending production of chemicals that destroy stratospheric ozone. Chemicals that
cause the most damage will be phased out first. The phase-out schedule can be speeded up if an earlier end to production of
ozone-destroying substances is needed to protect the ozone layer. The table on this page on Ozone-destroying chemicals
includes "speeded-up" phase-out dates which were proposed by EPA in early 1993.
CFCs, Halons, HCFCs (hydrochlorofluorocarbons) and other ozone-destroying chemicals were listed by Congress in the
1990 Clean Air Act and must be phased out. The Act also lets EPA list other chemicals that destroy ozone.
EPA issues allowances to control manufacture of chemicals being phased out. Companies can also sell unused allowances to
companies still making the chemicals or can use the allowances, within certain limits, to make a different, less
ozone-destroying chemical on the phase-out list.
In addition to requiring the phasing out of production of ozone-destroying chemicals, the Clean Air Act takes other types to
protect the ozone layer. The law requires recycling of CFCs and labeling of products containing ozone-destroying chemicals.
The 1990 Clean Air Act also encourages the development of "ozone-friendly" substitutes for ozone-destroying chemicals.
CFCs from car air conditioners are the biggest single source of ozone-destroying chemicals. By the end of 1993, all car air
conditioner systems must be serviced using equipment that recycles CFCs and prevents their release into the air. Larger auto
service shops were required to start using this special equipment in January 1992. Only specially-trained and certified
repair persons will be allowed to buy the small cans of CFCs used in servicing auto air conditioners.
As CFCs and related chemicals are phased out, appliances and industrial processes that now use the chemicals will change.
For example, industrial and home refrigerators will be changed to use refrigerants that don't destroy ozone. In the meantime,
refrigerator servicing and disposal will have to be done in ways that don't destroy ozone. In the meantime, refrigerator
servicing and disposal will have to be done in ways that don't release CFCs. Methyl chloroform, also called
1,1,1-trichloro-Methyl chloroethane, which will be phased out by 1996, is a very widely-used solvent found in products
such as automobile brake cleaners (often sold as aerosol sprays) and spot removers used to take greasy stains off fabrics.
Replacing methyl chloroform in workplace and consumer products will lead to changes in many products and processes.
As substitutes are developed for ozone-destroying substances, before the chemicals can be produced and sold, EPA must
determine that the replacements will be safe for health and the environment.
Consumer Products:
Hair sprays paints, foam plastic products (such as disposable Styrofoam coffee cups), carburetor and choke sprays-all are
consumer products that may be regulated under the 1990 Clean Air Act. These products will be regulated to reduce releases
of smog-forming VOCs and ozone-destroying chemicals (CFCs and related chemicals).
By May 1993, consumer products containing CFCs and related chemicals identified in the 1990 Clean Air Act as most
damaging to the ozone are required to have a warning label.
All products containing less destructive ozone- destroying chemicals identified in the 1990 Act must be labeled by 2015.
Consumers should be aware of product changes and any safety or health problems that may be caused by the new ozone-safe
formulations. Material safety data sheets for the products should be read for health and safety information and information on
how to use and dispose of the product.
The 1990 Clean Air Act orders EPA to study VOC releases from consumer products and report to Congress by 1993 on
whether these products should be regulated. If they are to be regulated, EPA is to list the consumer products that account for
at least 80 percent of VOC releases, and issue regulations for product categories, starting with the worst polluters. Labeling,
repackaging, chemical formula changes, fees or other procedures may be used to reduce VOC releases.