The CFC phaseout is already producing benefits for the environment, businesses, and inpiduals. This fact sheet explains some of these benefits. Several case studies of successful conversions to alternatives are listed also.
The chlorofluorocarbon (CFC) production phaseout is an important turning point in the recovery of the ozone layer. Currently, we are experiencing depletion of approximately 3 percent at Northern Hemisphere mid-latitudes and 6 percent at Southern Hemisphere mid-latitudes, but if no action had been taken to limit CFCs, ozone depletion at mid-latitudes would eventually have reached 20 percent or more.
Because of the phaseout, CFCs are no longer accumulating in the atmosphere at an accelerating rate. CFC-11 and CFC-113 levels are decreasing, and CFC-12 levels are increasing but at a slower rate than in the past. If international agreements are adhered to, the ozone layer is expected to recover around 2050. Much more information on the science of ozone depletion is available online.
The phaseout of CFCs is expected to have direct health benefits over the next century, including reduced incidence of skin cancer and cataracts, decreased risks to human immune systems, and increased protection of plant and animal life from excessive UV exposure. A United Nations Environment Programme (UNEP) study shows that a sustained 1 percent decrease in stratospheric ozone will result in about a 2 percent increase in the incidence of non-melanoma skin cancer, which can be fatal. With the successful phaseout of CFCs, however, EPA expects 295 million fewer cases of this form of skin cancer over the next century.
The CFC phaseout prompted research into alternative methods for cleaning applications in electronic assemblies and precision parts. Users often found that the need for chemicals during cleaning processes was reduced or even eliminated, while maintaining product quality and reducing costs. Precision ball bearings, medical devices, and sophisticated electronics components are now being produced using aqueous cleaning. New "no-clean" technologies eliminate the cleaning process altogether for printed circuit boards.
The CFC phaseout provided an impetus to develop and invest in a new generation of energy efficient air-conditioning and refrigeration equipment. Electric utilities have acknowledged this benefit by providing financial incentives for installing energy-efficient equipment. Aside from substantial lifetime energy and dollar savings, equipment upgrades also improve occupant comfort, system reliability, and operation and maintenance.
The Air-Conditioning and Refrigeration Institute (AHRI) reports that by 2000, 45 percent of existing chillers (large scale air conditioning units for buildings) were converted or replaced with equipment that uses non-CFC refrigerants. This conversion to more efficient equipment reduced energy use by almost 7 billion kilowatt hours per year, amounting to $480 million annual savings for new equipment owners by 2000.
The energy savings from equipment upgrades mean that less fossil fuels are burned at the power plant, leading to reduced emissions of air pollutants including carbon dioxide (CO2), nitrogen oxides (NOx), and sulfur dioxide (SO2). These pollutants are responsible for global warming and acid rain.
The CFC phaseout is a major component of the international effort to protect the stratospheric ozone layer. The phaseout relied on market forces to encourage development of CFC alternatives. This approach allowed CFC users to respond independently and creatively, often leading to improved technologies and cost reductions. The following are some examples:
The AGMC is a critical repair facility for military navigation and guidance systems. The center once consumed more than 2 million pounds per year of CFC-based cleaning solvents, and it faced a daunting challenge in making the transition to non-ozone-depleting substances. Missile guidance systems are so sensitive that parts must fit with clearances of only one to five microns (millionths of a meter), and the most minute residue can affect a missile's target accuracy.
The AGMC developed The Ozone Depleting Chemical Elimination program, and initiated testing of alternatives. By shifting to more benign cleaning techniques, the AGMC has virtually eliminated dependence on ozone-depleting chemicals. Aerospace and electronics companies have praised AGMC's cleaning processes. In 1995 the center won the Ford Foundation "Innovations in American Government" award.
In 1988, the makers of disposable foam cartons and food packaging announced a nation-wide phaseout of CFC use in food service packaging foams. At that time, about one-third of foam products for food service were manufactured with CFCs. This initiative, which relied on the adoption of alternative foam blowing agents, marked the first time an industry voluntarily halted use of CFCs. Cooperation between government, business, and environmental groups made this initiative successful.
AT&T was the first U.S. company to set a goal of phasing out CFC use by the end of 1994, and actually succeeded in doing so by 1993. To achieve this goal, the company tested and developed CFC alternatives for its manufacturing operations. These include terpene-based solvents and aqueous spray defluxers for use in cleaning circuit boards.
AT&T was also proactive in encouraging developing countries to support the CFC phaseout. The company sent managers and technical experts to Hungary, Japan, Singapore, the former USSR, and other countries to demonstrate the new technologies. AT&T also played a leadership role in the creation of the International Cooperative for Ozone Protection (ICOLP), an industry and government partnership to promote the benefits of global cooperation in protecting the ozone layer.
The CFC phaseout presents an ideal opportunity for building owners to capture energy savings by upgrading and modernizing air conditioning and refrigeration systems. A J.C. Penney retail store in Cumberland, GA implemented state-of-the-art lighting and other energy reduction measures, which in turn allowed it to install a smaller, more efficient air- conditioning and refrigeration system. This generated annual energy savings of 25 percent, amounting to $66,500/year. J.C. Penney also earned a $35,000 rebate from Atlanta Gas Light Company to defray new equipment costs.
1) small droplet or particle suspended in the atmosphere, typically containing sulfur
Aerosols are emitted naturally (e.g., in volcanic eruptions) and as the result of human activities (e.g., by burning fossil fuels). There is no connection between particulate aerosols and pressurized products also called aerosols (see below).
2) a product that relies on a pressurized gas to propel substances out of a container
Consumer aerosol products in the US have not used ozone-depleting substances (ODS) since the late 1970s because of voluntary switching followed by federal regulation. The Clean Air Act and EPA regulations further restricted the use of ODS for non-consumer products. All consumer products, and most other aerosol products, now use propellants that do not deplete the ozone layer, such as hydrocarbons and compressed gases.
Carbon tetrachloride was widely used as a raw material in many industrial uses, including the production of CFCs, and as a solvent. Solvent use ended when it was discovered to be carcinogenic. It is also used as a catalyst to deliver chlorine ions to certain processes. Its ozone depletion potential is 1.2.
CFCs are very stable in the troposphere. They move to the Stratosphere and are broken down by strong ultraviolet light, where they release chlorine atoms that then deplete the ozone layer. CFCs are commonly used as refrigerants, solvents, and foam blowing agents. The most common CFCs are CFC-11, CFC-12, CFC-113, CFC-114, and CFC-115. The ozone depletion potential (ODP) for each CFC is, respectively, 1, 1, 0.8, 1, and 0.6. A table of all ozone-depleting substances shows their ODPs, GWPs, and CAS numbers. CFCs are numbered according to a standard scheme. The National Oceanic and Atmospheric Administration provides more detailed information about CFCs on their web site (including graphs of their abundance in the atmosphere).
Class I substances listed in the CAA include CFCs, halons, carbon tetrachloride, and methyl chloroform. EPA later added HBFCs and methyl bromide to the list by regulation. A table of class I substances shows their lifetime ODPs, GWPs, and CAS numbers.
Title VI of the CAA directs EPA to protect the ozone layer through several regulatory and voluntary programs. Sections within Title VI cover production of ozone-depleting substances (ODS), the recycling and handling of ODS, the evaluation of substitutes, and efforts to educate the public.
Ozone levels can be described in several ways. One of the most common measures is how much ozone is in a vertical column of air. The Dobson unit is a measure of column ozone. Other measures include partial pressure, number density, and concentration of ozone, and can represent either column ozone or the amount of ozone at a particular altitude.
If 100 DU of ozone were brought to the Earth's surface, it would form a layer 1 millimeter thick. In the tropics, ozone levels are typically between 250 and 300 DU year-round. In temperate regions, seasonal variations can produce large swings in ozone levels. For instance, measurements in Leningrad have recorded ozone levels as high as 475 DU and as low as 300 DU. These variations occur even in the absence of ozone depletion, but they are well understood. Ozone depletion refers to reductions in ozone below normal levels after accounting for seasonal cycles and other natural effects.
The Federal Register is the formal method of communication for any Notice, Notice of Proposed Rulemaking (NPRM), or Final Rulemaking (FRM) issued by the US government. Once published in the FR, rules are collected in the Code of Federal Regulations. The FR is available at many libraries. FR cites ares similar in form to 11 FR 12345, where 11 is a number corresponding to the year (e.g., 62 is 1997) and 12345 represents the page number (pages are numbered continuously through the year; the first page published in each year is page number 1). Thus, a Notice whose cite is 62 FR 10700 was published beginning at page 10700 in 1997. It is usually helpful to obtain the date as well, since it is difficult to guess the date solely on the page number.
The GWP is the ratio of the warming caused by a substance to the warming caused by a similar mass of carbon dioxide. Thus, the GWP of CO2 is defined to be 1.0 . CFC-12 has a GWP of 8,500, while CFC-11 has a GWP of 5,000. Various HCFCs and HFCs have GWPs ranging from 93 to 12,100. Water, a substitute in numerous end-uses, has a GWP of 0. A table of all ozone-depleting substances shows their ODPs, GWPs, and CAS numbers, and another table shows the GWPs for many non-ozone-depleting substances.
The halons are used as fire extinguishing agents, both in built-in systems and in handheld portable fire extinguishers. Halon production in the U.S. ended on 12/31/93 because they contribute to ozone depletion. They cause ozone depletion because they contain bromine. Bromine is many times more effective at destroying ozone than chlorine. At the time the current U.S. tax code was adopted, the ozone depletion potentials of halon 1301 and halon 1211 were observed to be 10 and 3, respectively. These values are used for tax calculations. Recent scientific studies, however, indicate that the ODPs are at least 12 and 6, respectively. Note: technically, all compounds containing carbon and fluorine and/or chlorine are halons, but in the context of the Clean Air Act, "halon" means a fire extinguishing agent as described above. A table of class I substances shows their ODPs, GWPs, and CAS numbers. Halons are numbered according to a standard scheme.
Although they were not originally regulated under the Clean Air Act, subsequent regulation added HBFCs to the list of class I substances. A table of class I substances shows their ODPs, GWPs, and CAS numbers.
Hydrocarbons include methane, ethane, propane, cyclopropane, butane, and cyclopentane. Although they are highly flammable, HCs may offer advantages as ODSsubstitutes because they are inexpensive to produce and they have zero ozone depletion potential, very low global warming potential (GWP), and low toxicity. HCs are numbered according to a standard scheme.
The HCFCs are one class of chemicals being used to replace the CFCs. They contain chlorine and thus deplete stratospheric ozone, but to a much lesser extent than CFCs. HCFCs have ozone depletion potentials (ODPs) ranging from 0.01 to 0.1. Production of HCFCs with the highest ODPs will be phased out first, followed by other HCFCs. A table of ozone-depleting substances shows their ODPs, GWPs, and CAS numbers. HCFCs are numbered according to a standard scheme. The National Oceanic and Atmospheric Administration provides more detailed information about HCFCs on their web site.
The HFCs are a class of replacements for CFCs. Because they do not contain chlorine or bromine, they do not deplete the ozone layer. All HFCs have an ozone depletion potential of 0. Some HFCs have high GWPs. HFCs are numbered according to a standard scheme. The National Oceanic and Atmospheric Administration provides more detailed information about HFCs on their web site.
Methyl Bromide's chemical formula is Ch2BR. An effective pesticide, this compound is used to fumigate soil and many agricultural products. Because it contains bromine, it depletes stratospheric ozone and has an ozone depletion potential of 0.6. Production of methyl bromide will end in the U.S. on 12/31/2000. Much more information is available.
Methyl chloroform is used as an industrial solvent. Its ozone depletion potential is 0.11.
The Montreal Protocol on Substances That Deplete the Ozone Layer and its amendments control the phaseout of ODS production and use. Under the MP, several international organizations report on the science of ozone depletion, implement projects to help move away from ODS, and provide a forum for policy discussions. In addition, the Multilateral Fund provides resources to developing nations to promote the transition to ozone-safe technologies. The full text of the MP is available online and it is part of the OzonAction Information Clearinghouse database.
The nanometer, or nm, is a common unit used to describe wavelengths of light or other electromagnetic radiation such as UV. For example, green light has wavelengths of about 500-550 nm, while violet light has wavelengths of about 400-450 nm. One billionth is a tiny number. One foot is about one billionth the distance of 48 round-trips between Los Angeles and Washington, DC.
Ozone is a bluish gas that is harmful to breathe. Nearly 90% of the Earth's ozone is in the stratosphere and is referred to as the ozone layer. Ozone absorbs a band of ultraviolet radiation called UVB that is particularly harmful to living organisms. The ozone layer prevents most UVB from reaching the ground.
ODS include CFCs, HCFCs, halons, methyl bromide, carbon tetrachloride, and methyl chloroform. ODS are generally very stable in the troposphere and only degrade under intense ultraviolet light in the stratosphere. When they break down, they release chlorine or bromine atoms, which then deplete ozone. A detailed list of class I and class II substances with their ODPs, GWPs, and CAS numbers are available.
Stratospheric ozone is constantly being created and destroyed through natural cycles. Various ozone-depleting substances (ODS), however, accelerate the destruction processes, resulting in lower than normal ozone levels. The science page offers much more detail on the science of ozone depletion.
The ODP is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of CFC-11. Thus, the ODP of CFC-11 is defined to be 1.0. Other CFCs and HCFCs have ODPs that range from 0.01 to 1.0. The halons have ODPs ranging up to 10. Carbon tetrachloride has an ODP of 1.2, and methyl chloroform'sODP is 0.11. HFCs have zero ODP because they do not contain chlorine. A table of all ozone-depleting substances shows their ODPs, GWPs, and CAS numbers.
The ozone layer lies approximately 15-40 kilometers (10-25 miles) above the Earth's surface, in the stratosphere. Depletion of this layer by ODS will lead to higher UVB levels, which in turn will cause increased skin cancers and cataracts and potential damage to some marine organisms, plants, and plastics. The science page offers much more detail on the science of ozone depletion.
The stratosphere extends from about 10km to about 50km in altitude. Commercial airlines fly in the lower stratosphere. The stratosphere gets warmer at higher altitudes. In fact, this warming is caused by ozone absorbing ultraviolet radiation. Warm air remains in the upper stratosphere, and cool air remains lower, so there is much less vertical mixing in this region than in the troposphere.
The troposphere extends from the surface up to about 10 km in altitude, although this height varies with latitude. Almost all weather takes place in the troposphere. Mt. Everest, the highest mountain on Earth, is only 8.8 km high. Temperatures decrease with altitude in the troposphere. As warm air rises, it cools, falling back to Earth. This process, known as convection, means there are huge air movements that mix the troposphere very efficiently.
Ultraviolet radiation is a portion of the electromagnetic spectrum with wavelengths shorter than visible light. The sun produces UV, which is commonly split into three bands: UVA, UVB, and UVC. UVA is not absorbed by ozone. UVB is mostly absorbed by ozone, although some reaches the Earth. UVC is completely absorbed by ozone and normal oxygen.
UVA is not absorbed by ozone. This band of radiation has wavelengths just shorter than visible violet light. NASA provides more information on their web site.
UVB is a kind of ultraviolet light from the sun (and sun lamps) that has several harmful effects.particularly effective at damaging DNA. It is a cause of melanoma and other types of skin cancer. It has also been linked to damage to some materials, crops, and marine organisms. The ozone layer protects the Earth against most UVB coming from the sun. It is always important to protect oneself against UVB, even in the absence of ozone depletion, by wearing hats, sunglasses, and sunscreen. However, these precautions will become more important as ozone depletion worsens. NASA provides more information on their web site.
UVC is extremely dangerous, but it is completely absorbed by ozone and normal oxygen (O2).
EPA - U.S. Environmental Protection Agency