Research Projects

Project at a Glance

Project Status: complete

Report Published October 1992:

Title: Study of emissions and control of stratospheric ozone-depleting compounds in California

Principal Investigator / Author(s): Gibbs, Michael J.

Contractor: ICF Consulting Associates, Incorporated

Contract Number: A032-131

Research Program Area: Atmospheric Processes


The objective of this project is to compile data and analyses for the Air Resources Board (ARB) that will allow the Board and its staff to understand and assess the full range of issues regarding emissions of stratospheric ozone-depleting compounds (ODCs) and their control. The ODCs of interest in this study are the fully halogenated chlorofluorocarbons (CFCs), the partially-halogenated chlorofluorocarbons (HCFCs), the bromine-containing halon compounds, methyl chloroform and carbon tetrachloride. These compounds are currently the focus of national and international control efforts.

This report presents: (1) U.S. and California ODC emissions inventories for 1990 and 2005 that reflect current and expected future restrictions on ODC production, use and emissions, (2) detailed descriptions of the technologies available for reducing ODC use and emissions and (3) summaries of current federal, state and local legislation and regulations affecting ODC use and emissions.

Key conclusions drawn from the study include the following:

Future Emissions: Over time, U.S. ODC emissions will be eliminated by the ODC production phaseout mandated under the 1990 Clean Air Act Amendments and international agreements. Although U.S. production will be phased out in 1996, ODCs will continue to be emitted from products that contain them for at least 20 or more years after that time.

Control Measures: There are a large number of control measures for reducing ODC use and emissions. New chemical substitutes and processes are anticipated to be available for all new air conditioning and refrigeration systems. Alternative blowing agents are available for most types of foam production. Proven alternatives are available for all solvent cleaning needs, in particular the printed circuit board and electronics cleaning industries that are important in California.

Enforcement: In addition to phasing out the production of ODCs, federal rules being promulgated under the CAAAs cover a wide range of services and products found throughout the country. Local initiatives could assist in enforcing these requirements.

The Need for a Market in Recvcled ODCs: A market for recycled ODCs is needed. While the production of ODCs is phased out, existing air conditioning and refrigeration equipment will require ODCs for servicing. "Drop-in" substitutes are not expected to be available, and the retrofits required to accept the new refrigerants appear to be costly. Consequently, ODCs recovered from equipment being disposed must be made available to enable existing ODC-based equipment to be used for its expected useful life. The CAAAs require ODC recovery and recycling at both service and disposal. These requirements will help to create a supply of recycled ODCs.

Potential Control Gaps: Over the next 10 to 15 years, steps should be taken to ensure that the remaining available ODCs are used most effectively. By doing so, emissions will be minimized and the usefulness of existing ODC-based equipment will be maintained. The market for recycled ODCs should be monitored to assess whether interventions are needed to ensure the maximum possible recovery of ODCs during product servicing and disposal. In the event that the supply of recycled ODCs does not develop as currently expected, low-cost options for maintaining the usefulness of existing ODC-based equipment will require increased attention.

Additional Research Needs: By phasing out the production of ODCs, all ODC emissions will be eliminated. Currently, however, there are no provisions for preventing all the ODCs that were produced from being emitted eventually. In particular, ODC-based foams in buildings and appliances are expected to continue to emit ODCs slowly over many years. No cost-effective method of capturing these ODCs, even during product disposal, is currently available.

It is possible that recycled ODCs will remain available after ODC-based equipment is retired. In the event that more recycled ODCs are available than required, options for safely disposing of the chemicals may need to be developed. Over the long term, replacements for the transitional HCFCs will also be required. Demonstration projects for innovative cooling systems may be particularly valuable, as a variety of new chemical and process options are under development.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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