EP A/600/A-98/031 Research Agenda on Air Duct Cleaning Marie S. O'Neill USEPA Indoor Air Division Office of Air and Radiation Washington, DC 20460 Russell N. Kulp USEPA National Risk Management Research Laboratory Office of Research and Development Research Triangle Park, NC 27711 ABSTRACT The practice of air duct cleaning has the potential to affect the health and pocketbooks of millions of Americans, Duct cleaning practices currently include: source control by removal of contaminants from the air ducts and related heating, ventilating, and air-conditioning (HVAC) system components; application of antimicrobial agents to kill bacteria and fungi; encapsulates and sealants to contain imbedded contaminants; and the introduction of ozone to mask odors and kill microbiological organisms. All of these have the potential to affect indoor air quality (I AQ) in homes, office buildings, and other indoor environments. Recent surveys place the air duct cleaning industry's annual revenues at between $100 million and $700 million. In addition to the direct costs of acquiring duct cleaning services, long-term costs or savings may be experienced by the consumer due to duct-cleaning-related changes in energy use and health care expenditures. For these economic and public health reasons, reliable information is needed on the effects of air duct cleaning. Research funded by government, industry, and the private sector is contributing to an increasing understanding of the effects of these practices on IAQ and energy use, but more is needed to provide a sound basis for policymaking by governmental agencies concerned with: environmental health, decision-making by consumers, and standard-setting and certification by the duct cleaning industry. Four priority research areas are discussed for the purpose of reducing human risk and exposure to indoor pollutants: source removal/control techniques, application and use of antimicrobial agents, HVAC system sealants/encapsulants, and use of ozone in ventilation systems. INTRODUCTION Heating, ventilating, and air-conditioning (HVAC) systems can have a significant impact on indoor air quality (IAQ). In addition to providing thermal comfort, HVAC systems are typically designed to provide acceptable IAQ in occupied spaces by providing outdoor ventilation air and filtration (1). Outdoor ventilation air provides dilution and removal of indoor pollutants while filtration removes particles and other airborne contaminants before they are distributed by the HVAC system. This design can reduce occupant and system exposure to particles, including dirt, dust, fibers, combustion products, and microbiological contaminants (2). A recent Environmental Protection Agency (EPA) report indicates that HVAC components such as coils, fans, and duct surfaces can become contaminated with particles as a result of inadequate filtration and improper maintenance, and in fact can act as a source of IAQ problems (3). In the presence of sufficient moisture, particle contamination can act as a nutrient base for microbial growth. The literature shows broad agreement regarding the negative impacts that particulate and microbiological contaminants can have if they become airborne in occupied indoor environments. Sick Building Syndrome (SBS) may 1 ------- be caused partly by the allergic or irritant effects of indoor airborne contaminants. Contaminants, including microorganisms, could come from the HVAC system, which acts as a reservoir (4), Because the activities of the duct cleaning service industry may affect the levels of airborne contaminants indoors, they can play an important role in determining IAQ. THE AIR DUCT CLEANING INDUSTRY 1994 National Air Duct Cleaners Association (NADCA) estimates suggest that over 1,000 companies offering duct cleaning services are in business in the United States, approximately 25% of which are NADCA members whose proprietors agree to abide by the Association's professional and ethical standards (5). Consumers of air duct cleaning services include homeowners and residential property managers, managers of large commercial buildings, industrial facilities and food service establishments, and hospital administrators responsible for maintaining sterile conditions in surgery rooms and other health-care facilities. Although a number of guidelines and recommendations on the performance of duct cleaning services have been published (6,7,8), and NADCA is in the process of developing a voluntary industry certification program (9,10), no industry-specific regulatory program exists on a nationwide basis. Duct Cleaning Practice and Technologies NADCA defines the profession of air duct cleaning as "The safe removal of unwanted substances and foreign materials for the purpose of eliminating conditions that are potentially harm till to the health, well being, or productivity of building occupants, or that impede the performance of the HVAC system" (7). In addition to source control by removal of contaminants from the air ducts and related HVAC system parts, other practices sometimes employed by duct cleaning companies include the application of antimicrobial agents to kill bacteria and fungi, deodorizers to mask odors, encapsulants and sealants to contain imbedded contaminants or prevent fiber shedding from duct insulation or fibrous glass duct board; and the introduction of ozone to reduce odors and kill microbiological organisms. Source Removal. NADCA's recommended method of contaminant control is source removal by mechanical means. Current technologies include air washing with compressed air, contact vacuuming, and power/rotary brushes (7,8). These techniques are used to physically dislodge and loosen the dirt and debris accumulations from various HVAC component surfaces such as cooling and heating coils, plenums, equipment housing, and ductwork surfaces. To remove the contaminants, a high volume vacuum system is employed to collect and extract the dirt and debris. Effectiveness of these source removal methods is dependent on two elements: a) physical contact to dislodge the dust and dirt, and b) extraction once the dust and dirt is dislodged. , Interior surfaces ofHVAC systems may accumulate particles from a variety of indoor sources: skin flakes; cellulose and synthetic fibers; human, cat, and other animal hairs; fiberglass; pollen and plant materials; wood fragments; and combustion products, including tobacco smoke (11). Particles from ambient sources also can also represent a source of dirt and dust accumulation (12,13). Some IAQ investigations link elevated particle levels with increased incidence of various symptoms known collectively as SBS. Application of Antimicrobial Agents. Microorganisms that exist in indoor environments have been widely studied and in most cases are well characterized; these generally include protozoa, algae, viruses, bacteria, and fungi. Studies show that microbiological proliferation in the HVAC system can occur when the temperature range is appropriate and water and nutrients are present. Microbiological proliferation, in the HVAC system has the potential to be detrimental to the health of building occupants. The growth or amplification of microorganism colonies and the accumulation of other biocontaminants in indoor environments have been associated with human-health effects, including allergic and irritant responses. 2 ------- infectious diseases, respiratory problems, and hypersensitivity reactions (14), For this reason, control of microorganisms is an important goal for those involved in maintaining the quality of indoor environments. Antimicrobial pesticides are sometimes employed in control efforts. To be used legally in the United States, all pesticides, including microbiocides, or antimicrobial pesticides, must be registered by EPA in accordance with the Federal Insecticide, Fungicide, and Rodenticide Act (15). EPA registers antimicrobial pesticides under four different classes: • Sterilants are intended to destroy viruses and all living bacteria, fungi, and their spores on inanimate surfaces; * Disinfectants are intended to destroy or irreversibly inactivate infectious or undesirable bacteria, pathogenic fungi, or viruses on inanimate surfaces; * Sanitizers are intended to reduce the number of living bacteria or viable virus particles on inanimate surfaces, in water, or in air; and ~ Bacteriostats are intended to inhibit the growth of bacteria in the presence of moisture. Some registered products also may make a deodorizing claim if they kill microbes that cause odors (16). To be used legally in conjunction with air duct cleaning practices, antimicrobial pesticides must be registered with EPA for use in HVAC systems and used according to label directions (17). On the basis of currently available information, the EPA registers only sanitizing claims applied to thoroughly precleaned, non-porous HVAC system surfaces. SUBDIVISION H, LABELING GUIDELINES FOR PESTICIDES USE DIRECTIONS, has the following guidance: "(c) Special Directions for Use to Sanitize Hard Surfaces Associated with Ventilation and Air Conditioning Duct Work. "If a product is intended for use as a sanitizer on the hard surfaces associated with ventilation and air conditioning duct work, the directions for use should include the following items. "(1) For fogging applications, based on toxicity, labeling must bear specific directions stating if inhabitants are to be evacuated prior to application of the product. Furthermore, labeling should specify the amount of time that must elapse following application of the product before inhabitants can re-enter and occupy the building, including the necessary aeration and ventilation time periods. "(2) Prior to sanitation, duct work must be manually or mechanically cleaned, vacuumed, using high powered industrial strength vacuums, or blown free of dirt, dust, mold, and debris, using a commercially available duct cleaning system or service. "(3) To apply, spray or fog sanitizer solution into duct work to be sanitized, using a suitable spraying or fogging device and ensure that all surfaces are thoroughly wet for at least ten (10) minutes. Active solutions may be irritating when breathed; therefore, always use a suitable protective breathing apparatus when fogging or spraying these solutions. After application, allow surface to air dry. Always apply freshly made solutions of the product." Sealants and Encapsulants. Sealants and encapsulants are used to contain contaminated porous duct liners and to prevent or minimize the shedding of fibers from insulation or fibrous glass duct board material. Some assert that encapsulation provides a reduction of risk from air contaminants by fibers released from damaged internal duct linings, particularly in situations where full replacement of damaged lining is cost prohibitive, but to date, there is no published evidence to support this conclusion. Little reliable information has been published regarding the effects of their use on 1AQ or their efficacy in providing a complete or long-term barrier to microbiological growth. Because of the lack of information, and because sealants and encapsulants alter the surface burning characteristics of the fibrous glass duct insulation and thus void the fire safety assurance of the ductwork, EPA and National Institute for Occupational Safety and Health (NTOSH) have recommended that they not be used (6). Ozone. Because ozone (03) is a powerful oxidizing agent, it has been found to be very effective in neutralizing odors. Consequently, it is used extensively in restoration activities associated with fire 3 ------- damage. It has been long used as a germicide to disinfect drinking water and wastewater from municipal water treatment plants. Recently there has been an upsurge of interest in using ozone to "clean" or "treat" indoor air, and room and household ozone generators are being marketed and used for indoor air purification to destroy odors, volatile organic chemicals (VOC's), and microorganisms (18). There is some controversy surrounding the use of ozone for these purposes: recommended safe concentration levels may be exceeded; ozonation, the process of ozone reacting with VOC's, can produce toxic byproducts such as formaldehyde; and the capability of ozone as a biocide is largely unknown. Economic and Health Impacts of Duct Cleaning Recent surveys place the air duct cleaning industry's annual revenues at between $100 million and $700 million (19). The average residential duct cleaning job costs the consumer between $200 and $500 (5). In addition to the direct costs of acquiring duct cleaning services, long-term costs or savings may be experienced by consumers due to increased system energy efficiency and health-care expenditures. Health-care costs may change if IAQ is improved or worsened by duct cleaning and associated activities. Some duct cleaning companies appeal directly to health concerns by suggesting that their services will reduce allergic reactions and other health symptoms by making the client's indoor air cleaner and healthier (3). Energy efficiency may be enhanced if clogged or obstructed ducts and HVAC components are cleaned (20,21). Current Knowledge on Duct Cleaning Effects Few articles and studies provide scientific information on which to base evaluations of the effects that duct cleaning practices and technologies have on IAQ and system performance, including energy conservation, ventilation efficiency, operations, and maintenance. Below is a summary of some recent information on practices employed by the duct cleaning industry. Source Removal: Source removal by air duct cleaning companies may reduce airborne particle counts and levels of biological contamination in the indoor environment. However, little scientific information is available to evaluate effectiveness, methods, procedures, techniques, and technologies currently being employed (22). Two studies illustrate our current level of understanding and represent rare attempts to apply uniform analytical techniques for measuring ventilation effectiveness, cleaning effectiveness, and dust and microorganism levels in several residences where duct cleaning was applied. One study of source removal in residences was performed by The Canada Home Mortgage Corporation (23). Initiated in response to consumer inquiries regarding the effectiveness of air duct cleaning, the study was performed in 33 homes. The conclusions were; 1) cleaning did not have a significant effect on levels of airborne dust in the house, 2) increased energy and ventilation efficiency were not realized after air duct cleaning, 3) air duct cleaning was effective in removing dust and debris from duct surfaces, and 4) the effects of cleaning on concentrations of airborne microorganisms could not be determined on the basis of the study. Another study by the Florida International University (24) evaluated airborne particle and bioaerosol concentrations in eight residences using NADCA recommended source removal practices and technologies. The study found that: 1) short-term airborne particulate counts increased during the cleaning process but decreased as a result of cleaning, 2) no appreciable levels of fiberglass particles were generated after the duct cleaning process, and 3) airborne microbials increased during the cleaning process but decreased as a result of the cleaning. Application of Antimicrobial Agents: Antimicrobial agents are used by some air duct cleaning companies to mitigate the growth of microorganisms that are commonly found in HVAC systems. These agents achieve their result by killing or otherwise rendering inactive the microorganisms they contact. The findings from a recent EPA biocontaminant workshop illustrate the limited knowledge of the use of 4 ------- biocides as an TAQ control strategy (25). Experts agree that not enough information is available to determine the efficacy of biocides as a preventive or mitigativc control strategy in HVAC systems. Exposure to airborne biocides may cause health effects as detrimental as or worse than the health effects caused by exposure to the biocontaminants that the biocides are intended to control. Additionally, the effectiveness of these agents applied under real-life conditions and the longevity of the antimicrobial effect are not well studied. Experts have also expressed concern that antimicrobial agents registered only for outdoor activities are being used in HVAC systems [ibid]. Sealants and Encapsulants: Sealing and encapsulating are control strategies that can be either preventive or mitigative, depending on the application. Sealants are applied to duct surfaces in the manufacturing stage to prevent problems such as air leakage and fiber-shedding. When sealants or encapsulants are applied to already-installed ductwork, it is generally to mitigate an existing problem, such as particulate buildup, embedded microbial contamination, or duct leakage. The use of encapsulants and sealants may be seen as an economical alternative to total replacement in buildings with known microbiological contamination in the porous (duct linings) components of the HVAC system. Very little research on the TAQ effects and effectiveness of this practice exists. Some evidence suggests that sealing unlined ductwork may have a beneficial effect on 1AQ and energy efficiency by reducing infiltration into return air ductwork and exfiltration from supply air ductwork. Research on polymer-based sealants for unlined ducts is currently underway at Lawrence Berkeley Laboratories (26). Preliminary results suggest that application of the sealants may result in energy savings. Common sense also indicates that reduced leakage would prevent contamination from infiltrating the duct work from the plenums or other spaces through which it is routed. Ozone: Ozone gas forms when short wave ultraviolet light reacts with oxygen molecules. It is also produced by electrostatic fields such as those used to ionize and collect airborne particulate matter in electrostatic air cleaners (27). Ozone has been used effectively to deodorize and sanitize drinking water for many years. Ozone is now being used for indoor air treatment, especially for odor control and as a biocide. The action of ozone can reduce many household odors as well as the smell of environmental tobacco smoke. These benefits are a direct result of the highly reactive nature of ozone. Drawbacks to the use of ozone are also linked to its unique properties. Ozone is a lung irritant, and the concentrations required for effective deodorizing may exceed health-based standards. As a biocide, preliminary research seems to indicate that ozone is severely limited by the high concentrations required to attain a complete kill of microbial contamination (18). Because ozone is so reactive, undesirable byproducts such as formaldehyde can be produced as a result of the application (28). Lack of scientific and health effects data has not deterred the widespread use of ozone generators as a cure for many IAQ problems; hotels and motels routinely use them to "freshen" guest rooms; restaurants and bars use them to eliminate • tobacco odors; and schools use them to mitigate mold and mildew (18). Planned Research on Duct Cleaning Evidence exists that HVAC systems can act as sources of indoor pollutants (3,29). Small companies, such as carpet cleaners, chimney sweeps, and air-conditioning contractors, provide duct cleaning as an additional service, contributing to the growth of the industry. An abundance of equipment and technologies arc available for duct cleaning companies, but their use is unregulated, and the development of voluntary industrywide standards and certification programs is still in process (9). Much of the developmental standards and methods work has been accomplished by NADCA, the Association of Specialists in Cleaning and Restoration (ASCR), and the North American Insulation Manufacturers Association (NA1MA) based on case studies and field experience. Additional research could provide more information to address consumer and building manager concerns about if and when to clean, how to 5 ------- select a duct cleaning contractor, how effective cleaning is, or if cleaning can actually improve IAQ and save energy. EPA has planned a scientific research program for the purpose of developing qualitative information and data. Research related to source removal in residential systems is being funded with assistance from trade associations (NADCA, NAIMA, and ASCR). The objectives are to develop methods, protocols, and test procedures to evaluate the effectiveness of air duct cleaning technologies and to determine the impact on IAQ and energy. Testing methods to determine cleaning effectiveness for porous surfaces, such as ductliner and ductboard, are also being investigated. The research is being conducted in two phases: a pilot scale and a field scale. The duct cleaning industry plans to use the results to develop and improve voluntary standards and certification programs, Future EPA research plans include similar source removal research and studies in large commercial buildings (30). Scientific research related to microbial contamination shows that our knowledge is at a basic level. Most of the current research focus is on understanding the fundamental mechanisms that introduce, amplify, and disperse microorganisms in HVAC systems. Experts agree that prevention and control strategies cannot be adequately developed without reliable fundamental information. To address this need, the EPA and others are conducting chamber studies to better understand material colonization by microorganisms. Pilot-scale test rooms are being utilized to provide a better understanding of biological dispersion characteristics within ITVAC systems (25). Most of the current research on biocides has been done by manufacturers primarily for the purpose of bringing a product to the marketplace. Biocides are used in two ways: mitigation and prevention. Prevention involves incorporating the biocide into the manufacture of a product, such as contained in air filters or ductliners. Mitigation involves using biocides in a field application, such as wiping or fogging in HVAC systems. Planned research by the EPA will focus on mitigation techniques, efficacy, and associated health effects. The health effects of the biocide compared to those of the biocontaminants are not well understood [ibid]. Possible Areas for Future Research Emphasis A Committee on the Health Effects of Indoor Allergens, convened between 1991 and 1993 by the Institute ofMedicine, recognized the important role that duct cleaning practices may play in influencing exposures to airborne allergens. The Committee recommended research to evaluate the role of duct cleaning in controlling allergenic diseases (31). The Committee also recommended the minimization of allergen reservoirs and amplifiers through improved design, installation, use, and maintenance of HVAC equipment, and the development of recommendations and guidelines for moisture and allergen control in buildings. This last recommendation conveys the idea that duct cleaning is one practice among many that may affect the levels of pollutants in indoor environments. Research consistent with the Institute ofMedicine recommendations is being undertaken by a variety of groups, as indicated previously. Further research in several areas would also advance knowledge in the field. Duct Contamination Prevention. Filtering supply air, limiting duct leakage by sealing duct seams and joints, controlling humidity levels, and establishing proper pressure relationships in the HVAC system are all practices that can prevent contamination from entering or proliferating in the ductwork in the first place. An analysis of the sources of duct contamination (e.g.. relative contributions from indoor sources/outdoor sources) could be of value in establishing baseline knowledge on which further work could be based. Additional research that could aid in developing preventive strategies includes: • long-term studies comparing the effects of various filtration technologies and practices on the cleanliness of the HVAC system; • investigations of the efficacy of products and processes used in the design, installation, and maintenance of ducts for the purpose of minimizing leakage; and 6 ------- • research into various methods for controlling humidity levels and preventing condensation. Benefits and Risks of Pesticide Applications: Inquiries to EPA from both consumers and practitioners reflect both confusion about and interest in the antimicrobial products that are registered for use in HVAC systems, and how and when they should be employed. A consumer fact sheet being prepared by the EPA and the Consumer Federation of America will provide basic guidance on the topic, but deeper exploration of the topic would be of benefit. A survey of current practices with regard to the use of antimicrobial agents in HVAC systems and their components, retrieval and review of current registrations and supporting data, and development of standard protocols for field testing antimicrobial efficacy in HVAC systems and their components would give valuable baseline information from which specific investigative efforts could be launched. Additional studies focused on health concerns would be of use as well. These might address: • the possible adverse health effects from these agents during and after use in HVAC systems; • the likelihood of exposure in occupied spaces during or after use under various protective scenarios; • the evaluation of the physical properties of the agents for estimating the risk of exposure at room temperature and at elevated temperatures; and • the health impacts of exposures to pesticides compared to those from exposure to microbial contaminants that may be spread to the occupied space by the HVAC system. Sealing/Encapsulation: Two general purposes for sealing and encapsulating have been described: reducing duct leakage and adhering contamination to the ductwork to prevent its release to the indoor environment. In spite of governmental recommendations against the latter practice, it appears to be in use for economic reasons. An assessment of current practices with regard to sealing/encapsulating product choice, application techniques, and HVAC system conditions for which the process is chosen could be useful for directing further investigation. Additional issues of interest include: • possible health impacts to occupants from exposure to sealing/encapsulating agents; • durability of the agents; and • long term cost analysis of encapsulation/sealing vs. replacement of contaminated duct work or duct lining. Risks and Benefits of Ozone Decontamination: Several studies on the use of ozone generating products in conjunction with duct cleaning practices are possible. Valuable information could be derived from studies that: • compare the levels of ozone found in occupied spaces during, and at various time intervals after differing use scenarios (e.g., use of one product for different durations or settings, or use of different products); • test the efficacy of ozone in reducing odors or killing microbial contamination under various use scenarios; and • analyze the effects of ozone on textiles and furnishings in indoor environments. CONCLUSION The potentially high health and economic costs that duct cleaning practices may impose on a large number of Americans, combined with the relatively sparse body of published literature on the topic, suggest that high quality research on the effects of these practices on indoor air quality and energy use would be of value. Research results would provide bases for policymaking by governmental agencies concerned with environmental health; decision-making by consumers; and standard-setting and 7 ------- certification by the duct cleaning industry. ACKNOWLEDGMENTS The authors would like to thank the following people for their assistance and support with this article; Bob Axelrad, John Girman, Elissa Feldman, and Dave Mudarri with the EPA Office of Air and Radiation; Zigfridas Vaituzis with the EPA Office of Pesticides and Pollution Prevention; and Ray Steiber with the EPA Office of Research and Development, REFERENCES 1. ASHRAE. ASHRAE Standard 62-1989R, Ventilation for acceptable indoor air quality. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Atlanta, GA 30329, 1989, 2. Etkin, D.S. Particulates in Indoor Environments: Characterization and Health Effects. Indoor Air Quality Update. Cutter Information Corp. Arlington, MA 02174,1994. 3. Batterman, S. and H. Burge. HVAC systems as emission sources affecting indoor air quality: a critical review. Report No. EPA-600/R-95-014 (NTIS PB95-178596). Environmental Protection Agency. Research Triangle Park, NC 27711, 1995. 4. Smith, J.T. and C Wiech. Ventilation System Hygiene: A Review of Published Information on the Occurrence and Effects of Contamination. Research Report RR1:1995. The Chartered Institute of Building Services Engineers. London, England, 1994. 5. NADCA. NADCA Membership Survey Shows Industry Diversity. Ductales 6(4): 11, National Air Duct Cleaners Association. Washington, DC 20005, 1994. 6. EPA/NIOSH. Building Air Quality: A Guide for Building Owners and Facility Managers. EPA- 400/1-91-033 (GPO 055-000-00390-4). U.S. Environmental Protection Agency. Washington, DC 20460, National Institute for Occupational Safety and Health. Washington, DC 20000, 1991. 7. NADCA. Mechanical Cleaning of Non-porous Air Conveyance System Components: Standard 92-01, National Air Duct Cleaners Association. Washington, DC 20005, 1992. 8. NAIMA, Publication No. AH 112 9/92. Cleaning Fibrous Glass Insulated Air Duct Systems. North American Insulation Manufacturers Association. Alexandria, VA 22314, 1993. 9. NADCA. Quality Through Knowledge: An Introduction to NADCA's Certification Program. Ductales 1995a; _7(3): 6-7. National Air Duct Cleaning Association. Washington, DC 20005. 10. NADCA. An Introduction to Air Duct Cleaning Services. National Air Duct Cleaners Association. Washington, DC 20005, 1995b. 11. Hung, L-L. "Cat allergen in office buildings," in Proceedings of Assessing Microbiological Contamination of Indoor Environments. Fairfax, VA. Mid-Atlantic Environmental Hygiene Resource 8 ------- Center, Philadelphia, PA 19107, 1994, 12. McElroy, M.W., R.C. Carr, D S. Ensor, and G.R. Markowski. Size distribution offine particles from coal combustion. Science. 19S2:Vol. 215:p. 4,528. 13. Colome, S.D.. N.Y. Kado, P. Jacques, and M. Kleinman "Indoor-outdoor relationships of particles less than 10 /zm aerodynamic diameter (PM10) in homes of asthmatics," in Proceedings of Indoor Air '90: Fifth International Conference on Indoor Air Quality and Climate, 1990; Vol. 2: pp. 275-280. 14. Stetzenbach, L.D. "Microbiology of indoor environments," in Proceedings of Assessing Microbiological Contamination of Indoor Environments, Fairfax, VA. Mid-Atlantic Environmental Hygiene Resource Center, Philadelphia, PA 19107, 1994. 15. FIFRA. Federal Insecticide, Fungicide, and Rodenticide Act. P.L. 101-525, 1990. 16. Title 40, Code of Federal Regulations, Part 152, Section 15, Pesticide products required to be registered. U.S. Government Printing Office, Washington, DC 20402, 1995a. 17. Title 40, Code of Federal Regulations, Part 156, Section 10, Labeling Requirements. U. S. Government Printing Office, Washington, DC 20402, 1995b. 18. Steiber, R.S. Ozone generators in indoor air settings. EPA-6G0/R-95-154 (NTIS PB96-100201). National Risk Management Research Laboratory. U.S. Environmental Protection Agency. Research Triangle Park, NC 27711, 1995. 19. Future Technology Surveys. Survey on Air Duct Cleaning Services. Future Technology Services, Inc. Lilburn, GA 30247, 1993. 20. Zubair, S.M., V. Bahel, D.Y. Abdel-Nabi, and M. A. Abdeirahman, A Case Study for Improving Performance and Life Expectancy of Air-Conditioning Systems at a University Campus. ASHRAE Transactions. 95: 349-354. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Atlanta, GA 30329, 1989. 21. Dunbar, M., CleaningHVAC Equipment Saved California Retail Chain S37,000 in One Year. Energy User News. 14(4), 1989. 22. Luoma, M., A. Pasanen, P. Pasanen, and Y. Fan. Duct Cleaning-A Literature Survey. Air Filtration Review. Vol. 14, No. 4. International Energy Agency - AVIC, 1993. 23. Fugler, D. and M. Auger. "A first look at the effectiveness of residential duct cleaning," in Proceedings of the 87th Annual Meeting & Exhibition. Air & Waste Management Association. Pittsburgh, PA 15222, 1994. 24. Ahmed, I, B. Tansel, and J.D. Mitrani. Technical publication No. 113. Effectiveness of HVAC sanitation processes in improving indoor air quality. Florida International University, Miami, FL 33102, 1994. 9 ------- 25. Moore, M W. and E.J. Darden. 1994, in Proceedings of 1994 Indoor Air Biocontaminant Research Workshop. Research Triangle Institute, Research Triangle Park, NC 27709. 26. Carrie, F.R. and M.P, Modera. "Reducing the Permeability of Residential Duct Systems," in Proceedings of the 16th AIVC Conference Implementing the Results of Ventilation Research, 1995; Vol. 2: pp. 552-559. 27. Viner, A.S., P. A. Lawless, D.S. Ensor, and L.E. Sparks. Ozone generation in DC-energized electrostatic precipitators. IEEE Trans. Indus. Appl. 1992; (28) 3:504-512. 28. Wechsler, C., A. Hodgson, and J. Wooly. Indoor Chemistry: Ozone, Volatile Organic Compounds and Carpets. Environmental Science and Technology. 1992, 26: 2371-2377. 29. ASHRAE. Final report. ASHRAE RP-804. Identification of contaminants, exposures, effects and control options for construction/renovation activities. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Atlanta, GA 30329, 1995. 30. Kulp, RN., EPA Begins Air Duct Cleaning Research. Inside I AO. EPA's Indoor Air Quality Update. EPA/600/N-95/004, Spring/Summer 1995, p.10-11. Environmental Protection Agency, Research Triangle Park, NC 27711, 1995. 31. Pope, A. M., R. Patterson, and H. Burge, Editors. Indoor Allergens: Assessing and Controlling Adverse Health Effects. National Academy Press, Washington, DC 20460, 1993; p. 231. 10 ------- | NRMRL-RTP-P-077 gf wl^pic* || |||||| 1111111111111 111 111 fil ' BTf EPA/600/A-98/031 3, f PB98-140221 4. TITLE AND SUBTITLE Research Agenda on Air Duct Cleaning S, REPORT DATE 6. PERFORMING ORGANIZATION CODE 7. AUTHORiS) Marie S. O'Neill (OAR) and Russell N. Kulp (ORD) 8. PERFORMING ORGANIZATION REPORT NO. 9, PERFORMING ORGANIZATION NAME AND ADDRESS EPA, Office of Air and Radiation Indoor Air Division Washington, DC 20460 10. PROGRAM ELEMENT NO. 11. CONTRACT/GRANT NO. NA (inhouse) 12, SPONSORING AGENCY NAME AND ADDRESS EPA, Office of Research and Development Air Pollution Prevention and Control Division Research Triangle Park, NC 277E 13. TYPE OF REPORT AND PERIOD COVERED Journal article; 10-11/95 14. SPONSORING AGENCY CODE EPA/600/13 1^PLEMENTARVNOTESAPPCD project officer is RusseliN. Kulp, Mail Drop 54, 919/541- obi ems Conference, Engineering Solutions to IAQ is, abstract The article discusses four priority research areas aimed at reducing hu- man risk and exposure to indoor pollutants: source removal/control techniques; ap- plication and use of antimicrobial agents; heating, ventilation, and air-conditioning (HVAC) system sealants/encapsulants; and use of ozone in ventilation systems. All of these have the potential to affect indoor air quality (IAQ) in homes, office build- ings, and other indoor environments. For both economic and public health reasons, reliable information is needed on the effects of air duct cleaning. Research funded by government, industry, and the private sector is contributing to an increasing under- standing of the effects of these practices on IAQ and energy use, but more is needed to provide a sound basis for policymaking by government agencies concerned with: environmental health, decision-making by consumers, and standard-setting and cer- tification by the duct cleaning industry. 17. KEY WORDS AND DOCUMENT ANALYSIS a. DESCRIPTORS b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group Pollution Encapsulating Pollution Control 13 B 13 D Cleaning Ozone Stationary Sources 13 H 07B 13\iots Bacteria Indoor Air Quality 13 K 06M Air Conditioners Fungi Antimicrobial Agents 13A 06C Heating Odors 06P Ventilation Sealers HA 18. DISTRIBUTION STATEMENT 19. SECURITY CLASS (This Report/ Unclassified 21, NO. OF PAGES Release to Public 20. SECURITY CLASS (Thispage) Unclassified 22. PRICE EPA Form 2220-1 (9-73) reproduced a ------- |