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T!05390292

LBL-9578 EEB-Vent 79-19 VENTILATION AND ODOR CONTROL: PROSPECTS FOR ENERGY EFFICIENCY A Review of the Literature, with Reco~endations for Research Final Report of Phase I William S. Cain and Larry G. Berglund John Bo Pierce Foundation Laboratory New Haven, Connecticut Richard A. Duffee TRC Environmental Consultants Weathersfield, Connecticut Amos Turk City University New York City, New York November 1979 Prepared under UCLBL P.O. No. 4622602 for the Energy Efficient Buildings Program, Energy and Environment Division, Lawrence Berkeley Laboratory. Principal Investigators: Craig Hollowell and Arthur Rosenfeld. The work described in this report was funded by the Office of Buildings and Community Systems, Assistant Secretary for Conservation and Solar Applications of the U.S. Department of Energy under contract No. W-7405-ENG-48. T!05390293

VENTILATION AND ODOR CONTROL: PROSPECTS FOR ENERGY EFFICIENCY A review of the literature, with recon~endations for research William S. Cain, Principal Investigator Larry G. Berglund Richard A. Duffee Amos Turk Submitted by: /'~ohn B. Pierce Foundation Laboratory I 290 Congress Avenue INew Haven CT 06619 Date: November 1979 Prepared for: Energy and Environment Division Lawrence Berkeley Laboratory University of California Berkeley, CA 94720 -iii- T105390294

CONTENTS EXECUTIVE SUMMARY INTRODUCTION Odors Odor Sources and Energy Efficiency Energy Conservation and Ventilation Codes Plan of the Report INVESTIGATIONS OF VENTILATION REQUIREMENTS New York State Commission on Ventilation Derivation of Functional Relations ODOR CONTROL Deodorization of Recirculated Air by Granular Media Activated Carbon Other Granular Media Alternatives to Granular Media ODOR PERCEPTION Nonuniformity Nonlinearity Interactive Phenomena Lability Conmon Chemical Sense Physical Factors in Odor Perception and Ventilation Odor Perception and Health: Some considerations ANALYTICAL AND PSYCHOPHYSICAL MEASUREMENT SUMMARY AND PROSPECTS REFERENCES 7 12 24 24 25 28 30 32 32 34 36 38 40 41 46 48 53 56 oV- Ti05390295

EXECUTIVE SUMMARY Ventilation serves to dilute contaminants that arise in occupied spaces. Generally, the most bothersome contaminants comprise organic chemical substances present only in relatively small amounts. Even in small amounts, these may im- part a definite odor to a space. Accordingly, quantitative requirements for ventilation comprise, in effect, requirements for odor control. Because the odors of human bodies, tobacco, smoke, cooking, and waste defy simple analysis by instrumental means, the most direct way to decide ventilation requirements is to perform psycho- physical experiments. These can connect the magnitude and objectionability of odor to such variables as source and magnitude of contaminants (e.g., number of occupants, number of cigarettes smoked per hour), rate of ventilation, temperature, humidity, duration of occupancy, use of filter media, and various secondary variables. The realization that requirements for mechanical ventilation rest rather di- rectly on the need to control odors came about only gradually. Before the~l~, mechanical ventilation requirements were generally seen to arise from the need to control uncharacterized, but putatively toxic gases generated during occupancy. Thereafter, particularly during the 193Os, the basis for ventilation shifted from health effects to welfare effects. It then became clear that ventilation rates necessary to protect welfare (to eliminate annoyance, discomfort) offered more than enough air to protect health. Psychophysical experiments on occupancy odor, per- formed in that era, provided the underpinnings for modern ventilation standards. Those experiments, primarily the conception of C. P. Yaglou and associates, have exerted more leverage than ever i.ntended. Admittedly incomplete in their time, the experiments on ventilation requirements deserve reinspection and extension with modern facilities and modern methods of analytical chemistry, particulate monitoring, and psychophysical evaluation. Five broad issues of particular importance include l) the reported need for vastly higher ventilation rates per person under crowded than under uncrowded conditions, 2) the stability of various odorous contaminants (e.g., tobacco smoke odor) after removal of the source, 3) the role of temperature and humidity in the generation and perception of odorous contaminants, 4) the possi- bility that indoor air cleaning via filtration can eliminate the need for high quan- tities of ventilation air and can thereby save energy, and 5) whether results obtained in an "ideal" ventilation system (i.e., an aluminum lined room with precise control of environmental variables and air delivery) will generalize to field situations. These, and various associated issues (e.g., the contribution of particulate matter to tobacco smoke odor, the difference in odor tolerance between an occupant in a room and a visitor to a room), form the basis for newly begun laboratory and field experi- ments on ventilation and odor control, with particular emphasis on the quest for energy efficiency in ventilation. -vii- TI05390296

INTRODUCTION The indoor air generally contains a great variety of substances, organic and inorganic, present only in low concentrations. In a well-designed and well-tended building, these substances often exist at levels low enough to lack discernible impact on occupants. At levels high enough to have adverse impact, the substances are viewed as contaminants. A contaminant may act upon such biological targets as the airways, the liver, the central nervous system, and so on. Some contaminants may cause an immediate reaction, others a much delayed or a cumulative reaction. Some may pose little hazard when inhaled alone, but an amplified hazard when inhaled along with other contaminants. Some may have little impact on the majority of persons but a large impact on a sensitive minority. Generous ventilation has provided the traditional means to combat accumulation of indoor contaminants. Nevertheless, the cost of ventilation, on the average more than one-quarter of the operating cost of a building, increases proportionally with the cost of energy and therefore provides considerable incentive to search for energy efficiency. The present report will deal primarily with technical features of ventilation and the control of odorous contaminants. It will pursue a dual goal: to maintain acceptable air quality indoors and to achieve energy efficiency in the maintenance of air quality. Odors In addition to any ability to cause adverse impact, most airborne organic substances possess the con~non ability to excite olfaction (1). Many become detectable by smell at concentrations well below one part-per-million (ppm). Indeed, some evoke strong, even overpowering odors at concentrations in the ppm range. Like other sense modalities the sense of smell behaves as an adaptive channel of information. For instance, olfaction manages to block the ingestion of various unhealthful substances (e,g., spoiled meat} that might be deemed acceptable by taste. When used to evaluate the properties of substances taken into the mouth, olfaction serves as a "contact" sense in a manner similar to taste. Olfaction also serves as a "distance" sense, a channel for information about objects outside the body. When using the modality in this way, a person can readily succumb to the temptation to ascribe to the odorous air charac- teristics more properly attributed to the source of odorant. Hence, foul smell- ing air can seem dangerous in itself rather than merely a signal of the pre- sence of unsanitary conditions. A passage regarding the views of the eminent public health physician Charles V. Chapin illustrates a common-confusion (2): Probably the most conspicuous aspect of the sanitary environment of Providence (as of other cities) in 1884 was the stench. It had odors from its hundreds of stables, its polluted streams, its dead dogs or horses, and its thousands of foul privy vaults and cesspools. When the odors became so intense that even the people who lived among them were nauseated, it is no wonder that many persons associated diseases with bad smells. And when disease did come out of certain kinds of foul smelling dirt, it was only logical for people to fear and wish to eliminate filth ... Chapin did not fear odors as such. He was one of a few in America before 1885 who followed the English sanitarian John Simon in pointing out that the danger from filth was not in the stench but in specific disease germs. [p. 45] T105390297

In the late 19th century when physiologists began to experiment in earnest on the biological basis for ventilation, the question of acceptable odor levels indoors also attained prominence. Various scientists of the time considered the organic substances given off by human bodies as particularly harmful, even lethal (3): Organic matter is given off from the lungs and skin, of which neither the exact amount nor the composition has been hitherto ascertained. The quantity is very small, but of its importance there can be no doubt ... Since this organic matter has been proved to be highly poisonous, even apart from carbon dioxide and vapor, we may safely infer that much of the mischief re- sulting from the inspiration of rebreathed air is due to the special poisons exhaled by the body. Absence of techniques to detect small amounts of organic vapors meant re- liance on the nose as an indicator of safety. Since that era, it has become clear that body odor in particular carries little hazard. Nevertheless, through- out this time odors have never ceased to play a strong role in the determination of ventilation requirements. Whether for reasons of health or esthetics, odors will continue to figure in ventilation practice. Therefore, any effort to discover ways to conserve energy in ventilation must confront the issue of how odors arise, how they are perceived, and how to control them. Odor Sources and Energy Efficiency Odors may arise from almost any indoor activity. Tobacco smoke forms a par- ticularly notorious odor nuisance. Its persistence and its change in character over time (i.e., from fresh, but irritating, to stale and sour) account for much of its notoriety. Places of habitual smoking may never lose their odor even when ventilated continuously at very high levels. The cost of such high rates of ven- tilation gives incentive to displace or eliminate the source. Where possible, elimination of a source of odor provides the most economical and energy efficient means of control. Odor problems in the workplace, for instance, often arise from poor "housekeeping." The same can hold true in residences and in commercial and institutional buildings. Such housekeeping chores may include, among other things, cleaning of ducts and cooling coils and removal of. filters in a ventilation system. This kind of housekeeping acknowledges that the system may become a secondary source of odor from dust, bacteria, mold, spores, and adsorbed organic materials. I.n many instances, odors arise from sources (e.g., kitchen stoves, toilets) that allow some control of the source, but not complete removal. The most energy efficient means to cope with such high intensity sources may include local exhaust with perhaps some recirculation of the exhaust air. In general, however, odor con- trol will derive from the need to cope with such things as effluvia from bodies, emanations from building materials, and ongoing activities of occupants (e.g., eating, drinking). These matters require general ventilation and pose the energy relevant issue of whether a space should continuously'receive the amount of vent ]a- tion air dictated by the so-called design occupancy. Many spaces are commonly occu- pied at much lower levels. The matter of ventilation on demand, achievable through monitoring and control of concentrations of carbon dioxide, oxygen, carbon monoxide, or other, as yet, unspecified contaminants,will receive little direct attention here. Nevertheless, this manner of gaining control over the atmospheric environment in a building is potentially compatible with both high indoor air quality and low expen- diture of energy. 2 T!05390298

Energy Conservation and Ventilation Codes The present report will give primary consideration to odors, but will neces- sarily pay some attention to the thermal attribute of the indoor environment. These factors play companion roles. Ventilation can serve simultaneously to bring the indoor environment under thermal control, e.g., using outdoor air to cool a warm space, as well as to dilute chemical contaminants. Furthermore, occupants may confuse thermal and chemical attributes perceptually, viz., may decide that stuffiness arises from poor air quality as opposed to overly warm air. The intimate relationship between these factors takes on particular impor- tance in efforts to conserve energy. Any reduction in the amount of ventilation air normally necessary to control odors will reduce the energy consumed to heat, cool, humidify, or dehumidify that air. Such savings can add to those achieved through lowering the settings of thermostats in winter and raising the settings in summer. Within the last few years it has become common for jurisdictions to adopt model building codes. The codes include those of l) the Building Officials and Codes Administrators International (BOCA), used mainly in the midwest and north- east, 2) the International Conference of Building Officials (ICBO), used mainly in the west, and 3) the Southern Building Code Congress International (SBCCI) used mainly in the south and southeast. In some instances, a particular model code governs building practices in all local jurisdictions within a state. In other instances, local officials will have the opportunity to choose between the state code or a specified model code. In some states (e.g., Texas), one model code will prevail in one area and another model code in another area. Irrespec- tive of such seeming complications,the country has in fact begun to converge upon uniformity in building codes and accordingly in ventilation codes. In a particularly strong gesture toward uniformity, the three model code groups (BOCA, ICBO, SBCCI) worked together with the National Conference of. States on Building Codes and Standards (NCSBCS) to draw up an energy conservation code (The Code for Enerqy Conservation in New Buil.dinB Construction). This code, in actuality a section of a total code, has already become or wil'l become part of the BOCA, ICBO, and SBCCI model codes. The code for energy conservation finds its parentage in Standard 90-75 (Energy Conservation in New Buildinq Design) of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Table l shows that virtually all large jurisdictions have already or will soon conform to energy conservation standards through adherence to one or another model code or through the adoption of a separate state code rooted in a model code or ASHRAE Standard 90-75. Indeed, only five jurisdictions fail at present to show overt action toward the adoption of an energy-efficient code. The information in Table l was gathered by NCSBCS and disseminated on May 25, 1979. The ventilation component of the energy conservation model code derives from ASHRAE Standard 62-73, Standards for Natural and Mechanical Ventilation~ That standard lists ventilation requirements per occupant for a great variety of residential, commercial, industrial, agricultural, and institutional spaces. The standard specifies, space by space, two requirements: minimum and recom- mended. The recommended requirements actually form an interval, e.g., ]5-20 cfm (7.5 - lO L/s) per occupant. Minimum requirements fall on the average 30% below the midpoint of the recommended range. Table 2 gives examples for a few spaces. *Standard 62-73 is currently under revision. appear in 1980. 3 A revised standard will probably T105390299

Jurisdiction Table l NCSBCS Survey of Energy Conservation Codes Energy Conservation Code Jdrisdiction Energy Conservation Code Alabama SBCCI Nebraska (ICBO) Alaska (ASHRAE 90-75) Nevada MCEC Arizona (State Code)* New Hampshire MCEC Arkansas (State Code)* New Jersey BOCA California State Code New Mexico ICBO Colorado MCEC New York State Code* Connecticut State Code* North Carolina State Code Delaware (MCEC) North Dakota ICBO District of Ohio MCEC Columbia (City Code) Oklahoma None Florida State Code* Oregon ICBO Georgia MCEC Pennsylvania (ASHRAE 90-75) Hawaii ICBO Rhode Island ASHRAE 90-75 Idaho ICBO South Carolina SBCCI Illinois (State Code)* South Dakota (MCEC) Indiana MCEC Tennessee MCEC Iowa MCEC Texas (MCEC) Kansas State Code Utah MCEC Kentucky MCEC Vermont (ASHRAE 90-75) Louisiana (MCEC) Virginia BOCA Maryland (ASHRAE 90-75) ASHRAE 90-75 Massachusetts MCEC Washington State Code Maine (State Code) West Virginia None Michigan ASHRAE 90-75 Wisconsin State Code* Minnesota ASHRAE 90-75 Wyoming ICBO Mississippi (MCEC) American Samoa MCEC Missouri (MCEC) Guam ICBO. Montana MCEC Puerto Rico MCEC Key: ( ) Denotes Legislation Pending ASHRAE 90-75 ASHRAE STANDARD 90-75 BOCA Model Code, Building Officials & Code Administrators Inter- national, Inc. ICBO Model Code, International Conference of Building Officials MCEC Model Code for Energy Conservation in New Building Construction SBCCI Model Code, Southern Building Code Congress International,lnc. Asterisk(*) denotes obvious incorporation of energy conserving aspects of a model code or ASHRAE 90-75. Codes or pending codes for California, Maine, and North Carolina also include some such aspects. 4 Ti05390300

Table 2 Examples of Ventilation Requirements Per Occupant Recommended in ASHRAE Standard 62-73. Residential bedrooms Conference rooms (small) Public rest rooms Classrooms School libraries Minimum Recomended 5 cfm (2.5 L/s) 7-10 cfm (3.5-5 L/s) 20 (I0) 25-30 (12.5-15) 15 (7.5) 20-25 (I0-12,5) 10 (5) ]0-15 (5-7.5) 7 (3.5) I0-12 (5-6) ASHRAE Standard 90-75 on energy conservation specifies use of the minimum values from Standard 62-73. This means that new buildings should now deliver ap- proximately 70% of the outdoor air delivered prior to the energy conservation standard. These new recommendations have considerable impact because they form the ventilation recommendations of the Code for Energy Conservation in New Building Construction jointly prepared by BOCA, ICBO, NCSBCS, and SBCCI. In essence, then, the various code-bodies of the United States have shown a strong desire to achieve both uniformity and energy efficiency in ventilation. ASHRAE's assessment of ventilation requirements arises mainly from consensus regarding the outdoor air necessary to maintain indoor comfort. As will become evident below, the minimum requirements bear similarity to the outcome of laboratory research on the acceptability of odors generated during occupancy. Plan of the Report The remainder of this report will highlight the various factors that play a role in the determination of ventilation requirements for odor control. First, the report will review studies that uncovered and quantified the connection between odors and ventilation requirements. Although motivated by an interest in public health and hygiene, such studies were generally reported in the engineering litera- ture. Not surprisingly, therefore, most hygienists and public health specialists have traditionally paid little attention to chemical contaminants in the residential, commercial, and institutional environments. The presumed adequacy of ventilation has allowed such professionals to focus on chemical contaminants in the workplace and in the ambient air. Recent discoveries regarding excessive levels of formalde- hyde in buildings lined with chipboard (4), excessive levels of particulate matter in the vicinity of smokers (5), and excessive levels of oxides of nitrogen in homes with gas stoves (6), have, in conjunction with the need for energy efficiency, re- focused attention on the origin and adequacy of nonindustrial ventilation rates. Subsequent to a review of the research basis for modern ventilation rates, the varieties of odor control applicable indoors will receive attention. The section on control will deal at length with chemical and engineering considerations in the use of granular filter media, the most practical means of indoor odor control. In the present context, the term odor control refers to the elimination of small amounts of gaseous materials. Some such materials happen to evoke odor and provide no other incentive for control. Nevertheless, the control procedures will eliminate many T105390301