Click for next page ( 420


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 419
VTII EFFECTS OF INFER ~~=ION ON HAN PELF - E .Indoors. is the place of escape from extremes of temperature, humidity, and environmental conditions and from exposure to some pollutants found in the ~outdoors.. It is The place where rest, relaxation, and the general welfare afforded by bodily comforts are sought. It is known that attempts to reduce energy consumption in buildings can affect the quality of indoor environments. This chapter discusses some of the effects on human welfare--e.g., discomfort, decreased productivity, soiling, corrosion, and maintenance and housekeeping needs--caused by alterations in environmental control systems. Discomfort is the result of undesirable sensory stimuli. such as noise, malodors, glare, and extremes of humidity and temperature. These often invoke a human response, identified as ~discomfort,. that is straightforward and physical and that may sometimes be relieved by attenuation of the stimulus. However, mere attenuation of the sensory stimulus sometimes does not suffice. Discomfort is a sensitive indicator of the need for adjustments in environmental quality control. The relationships between indoor pollution and productivity can be evaluated only after one carefully def ines productivity and determines how it is to be assessed. Originaly, productivity was conceived simply as quantity of output; but it has come to be addressed in terms of economy--the cost per unit of production. This chapter discusses some a ttempts to measure the effects of environmental quality, with productivity as a tool. Indoor air pollution is a source of soiling and contr ibutes to the deter ioration and corrosion of equipment, furnishings, and appliances . Soiling increases needs for maintenance and housekeeping and for some equipment in the ventilation system. RELATIONSHIPS BEEN S=IO=ON~C STATUS AD I~R POLLUTION The relationships between housing characteristics and the health of the occupants among the various socioeconomic groups are not well known. The available information t although limited r iS important if we 419

OCR for page 419
420 are to understand and identify the problems involved and if we are to learn the relationships between housing types, housing quality. indoor environmental quality, and pollutant types, on the one hand, and the health and welfare of the people in the several socioeconomic groups, especially those in the lower groups, on the other hand. A comprehensive treatment of socioeconomic status (SES) and indoor air pollution may be important to the formulation of control strategies (local, state, or federal) in matter. that influence indoor pollution, such as energy-conservation assistance programs and low-income and rent-subsidy programs. Housing characteristics are related to social status or income level.' 5 S ~ ~ ~ Status and income often have been shown to be related to health and probably constitute an intervening variable in the relationship between selected housing characteristics and health. ~ ~ 5 The role of hous ing itself in determining health in still unclear . 33 ~5 S' `, l' Crowding indoors is thought to be an important contributor to the spread of infectious diseases and a potential source of physiologic stress. 51 67 l' A substantially higher proportion of persons in low-income groups have chronic health conditions that limit their activities ~ ~ and keep them indoors. Some character rustics of hous ing constitute def inite r isks to health--e.g., carbon monoxide poisoning from faulty venting of space-heating systemS72 and lead poisoning from paints.~. The two mentioned are also related to low-income houses, which often have greater rates of air inf titration and, because they are close to sources of pollution, transport pollution more freely from outdoors to indoors. as 5. Spivey and "dfordSt found that a high proportion of gas stoves and gas space-heaters (60% in lower-SES homes in east Baltimore) had higher indoor than outdoor concentrations of carbon monoxide (8-8.9 ppm versus 5.5-6.1 ppm). In two sets of homes studied, the amount of passive smoking did not appear to be related to any differences observed in indoor carbon monoxide concentrations e In over 70% of these homes, the lead content in dust and paint samples exceeded currently recommended standards. Blood lead contents are lower in persons who live in SES-~uivalent houses with air-conditioning than without. 2 Binder et a`. ~ 2 found that indoor respirable-particle concentrations were higher in homes with higher ratios of persons to room volume. The following tentative conclusions can be drawn: Momes with controlled ventilation systems, air filtration, good maintenance, and properly working appliances have lower concentrations of indoor pollutants. That implies that the middle and upper socioeconomic groups are at lower risk. However, there are sources of pollution other than those mentioned in upper-income houses, specifically, newer and more carpets, curtains, and furniture. Low-income housing is more likely to have improper ventilation, poor maintenance, defective appliances {such as improperly operating stoves and space-heaters), and lead-based paint--all of which contribute to higher indoor concentrations of pollutants. 2 0 S ~ S ~ ~ ~ Furthermore, persons in the low-income groups are more likely to live in mobile homes or apartments,' which frequently are crowded (high ratio of persons to

OCR for page 419
421 1 volume). 5 ~ Mobile homes generally are very airtight, and crowding can result in high concentrations of indoor pollutants.S. . Recreational vans and trailers have many of the physical characteristics of mobile homes and can have similar pollution problems . Those who can af ford to ~ tighten ~ the i r conventional home s for energy conservation may also have higher indoor concentrations of some pollutants, although one would expect on eventual balance between tightening ~ and proper ventilation in those homes . HUMAN DISCOMFORT The incentive to control the indoor environment is derived as much from consideration of human comfort as from consideration of health. Discomfort provides an immediate incentive to control the quality of the indoor environment. Undesirable sensory signals (e.g., noise, glare, and cold ~ register as discomfort . These signals have s traightforward physical correlates (e . ~ ., sound pressure , contrast ratio, and temperature) with the need for controls, such as the installation of sound-absorbing tiles. A person annoyed initially by the loud conversation of co-workers may eventually become annoyed even by whispered exhanges; thus, mere attentuation of noise may not suffice. A person annoyed frequently by sidestream cigarette smoke from the person at the next desk may eventually become angered by the slightest trace of tobacco-smoke odor. Such time-dependent changes in sensitivity show a cognitive contribution to discomfort. Some persons can become annoyed merely by the information carried by a stimulus, and this reaction can be as important as a reaction to the stimulus itself. Whether discomfort is caused by the intensity of stimulation or by the condi~cioned response resulting from sensitization, the questions ar ise: Will avoidance or elimination of discomfort ensure a reasonably healthful indoor climate? Does endurance of discomfort take a psychologic or physiologic toll? Our senses are remarkably adaptive. Therefore, they do not provide infallible sensory signals about the safety of the environment, owing to their inability to register some types of energy or potential stimuli . For instance, a person may view a solar eclipse without knowledge that the ultraviolet rays, unregistered by the photon receptors, may damage the eye. A person may bask in the warmth of the summer sun without awareness that ultraviolet rays, poorly registered in this case by cutaneous receptors, may cause serious, even lethal burns . S. imilarly, a person may eat a baster ia-laden, although delicious, meal without any sensory warning of the ptomaine toxins present. The sense of smell also fails to register some harmful stimuli, such as carbon monoxide. With only a limited number of notable exceptions, however, the absence of annoying stimuli indoors may be misleading, but generally does signify safe conditions of occupancy. Regarding the endurance of discomfort, possible long-term effects include irritability, depression, inability to concentrate, anxiety, indigestion, headaches, back pain, and insomnia. s7 Short-term

OCR for page 419
422 effects of discomfort are often rather specific to a particular modality. Hence, n~alodors may cause symp tome of digestive upset, poor lighting may cause headaches, and cold drafts may cause muscle stiffness. Objective verification of direct causes of these various symptoms is difficult. For this reason, the symptoms, even when severe, fail to qualify as adverse health effects. This section briefly discusses some of the indoor-polution aspects of discomfort. MALODORS The olfactory senses signal the presence of some harmful airborne stimuli, but sometimes they fail to do so, and there are frequent ~ false alarms. ~ As mentioned in Chapter IV, people have historically avoided bad-smelling air for fear that it signaled illness-causing conditions. In the nineteenth century, the criteria for ventilation commonly arose from the notion that odorous air contained harmful ingredients known variously as crowd poison, morbific matter, and anthropotoxin. ~. For instance, Russell stated in The Atmosphere in Relation to Human Life and Health: s 2 Organic matter is given off from the lungs and skin, of which neither the exact amount nor the composition has been hitherto ascertained. Their 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 resulting from the inspiration of rebreathed air is due to the special poisons exhaled by the body. In the absence of ins trumentation to detect the presence of small amounts of odorous organic vapors, the nose remains a sensitive ind icator . Surpr is ingly, even today there are no good rules for laymen or scientists to relate perceived odor quality to toxicity. Some odorous signals are used to warn about toxic hazards (e.g., mercaptans a re used in natural gas to s ignal leaks ~ . We may know f tom exper fence that some foul-smelling living spaces pose no overt danger, but people will still avoid such places. We may argue that this avoidance is derived from mere discomfort, but occupants may fail to see the s ituation in such benign term. In the early twentieth century, the New York State Commission on Ventilation performed a set of experiments regarding the effect" of occupancy odor on human comfort and performance. In a popular synopsis of this 8-yr effort, Winslow7 stated: We may summarize our discussion of the physiology of ventilation as follows: The chemical vitiation of the air of an occupied room (unless poison '3 or dusts from industrial processes or defective heating appliances are involved) is of relatively slight importance. The organic substances present,

OCR for page 419
423 manifest as body odors, may exert a depressing effect upon inclination to work and upon appetite; therefore, occupied rooms should be free from body odors which are obvious to anyone~entering from without. {Such odors are never perceived by those who have been continuously in the room while they have been accumulating. ~ Objectionable effects of this sort have only been demonstrated, however ! with a carbon dioxide content of over .2 per cent, which would correspond to an air change of less than 6 cubic feet per person per minute. During the 1930s, Winslow and Berrington, ~ demonstrated that adult odor. similar to that from a heating system could also depress appetite. Winslow implied that the olfactory sense generally adapts to prevailing odorous stimulation in such a way as to reduce discomfort. Similarly, Cain reported that a temporary reduction in olfactory sensitivity, perhaps in conjunction with affective habituation, presumably explains why workers in some malodorous industries eventually find the odorous atmosphere unobjectionable.' In contrast, people who live near malodorous sources of pollution seem to exper fence adverse olfactory reactions of constant or even increasing severity. For example, residents exposed frequently to malodorous emiss ion of factor ies complained of chronic headaches, nausea, coughing, disturbance of sleep, and loss of appetite. `. Those adverse reactions seem to arise as a consequence of industrial odors that are more or less unremitting and are beyond the residents ' control. But when the source is in the occupied space, some control {or avoidance ~ may well be possible . {Tobacco smoke, traditionally the most bothersome odorant, is a common exception. ~ Complaints about irritation of the eyes, throat, and nose are common and increasing among people in newly constructed or newly renovated offices.. These complaints may arise from a confluence of low, energy-conserving races of ventilation and emission of odorous or irritating substances, such as formaldehyde, from new furnishings. Tobacco smoke may exacerbate the problem. The course of the reaction of the common chemical sense of those exposed may vary considerably.)' One person may notice irritation immediately; another may notice it only after occupying a space for a few hours, but continue to experience it long after leaving the space and possibly fail to associate the irritation with its source. As a further complication, it has long been suspected that formaldehyde acts as an olfactory anesthetic. S. NOISE Discomfort due to noise has received more attention than that related To any other type of sensory stimulation. Noise-induced discomfort occurs in a great variety of situations, ranging from disturbance of sleep to difficulty in hearing in the workplace. Noise s tandards and regulations abound: for outdoor noises, for sound insulation in buildings, for controlling the risk of occupation-related deafness, and for guarding against hear ing dif f iculty and annoyance in

OCR for page 419
424 offices, schools, and hospitals. The context can have a strong bearing on the degree of annoyance. Nemecek and Grandjean.5 surveyed a large office and found that most of the employees were disturbed by noise that was considered well within professional design standards. The ~noise. came from conversations, and it was content, rather than intensity, that was the disturbing attribute . Exper ireents in both human beings and animals have shown that stressful effects from nondeafening noise arise without respect to the ~meaning. of the auditory stimulation. ~ 2 Physical attributes that seem particularly relevant to annoyance include intensity, concentration of energy within high frequencies, temporal and spectral complexity, duration, and the suddenness of sounds.~. Table VIII-1 shows results of a survey made to determine the importance of var ious physical and perceived attributes of annoying sounds. 2 ~ The respondents judged loudness the most important attribute, with suddenness next in line. The next three most important attributes comprised cognitive features (sound is man-made, sound cannot be turned off, sound is unnecessary). The preeminence of loudness in the determination of annoyance has led to recommendations, such as those in Table VIII-2, for tolerable maximal loudness in various types of rooms. The loudness value. listed here refer to continuous noise in the period between 7 a.me and 10 p.m. Both human and animal laboratory exper iments have shown hormonal effects of noxious, although nondeafen~ng, noise exposure. Even exposures of about 70 dB can increase the output of adrenal corticosteroids. ~ 2 ~ Sound intensity this low can also cause constriction of peripheral blood vessels. 38 Such changes, and other physiologic manifestations, usually fail to outlast the stimulus, but do cause concern that noise might eventually lead to more chronic symptoms of stress or af feet sleep. Frequent interruption of sleep or a iteration in the normal progress ion of sleep patterns may be thought to jeopardize physical or mental health eventually. Fortunately, adaptive alterations in the pattern of sleep seem to minimize most short-term consequences of disruption by noise.32 In addition to physiologic manifestations, noise exposure produces adverse behavioral manifestations. Experimental exposure to noise diminished the quality of interpersonal contact,iS increased aggressiveness, 2' and impaired willingness to help persons in need. Loud noise, particularly intermittent noise, may alter productivity. The effect may be facilitative, rather than inhibitory; that has led to the speculation that noise may interact with other environmental factors and with personal factors to achieve a degree of arousal desirable for work. 2' TEMPERATURE There is little scientific information on the connection between thermal conditions and productivity. In laboratory experiments at 65-85F (18-29C), productivity often reached a peak at nonpreferred temperatures. In an apparel factory. productivity (i.e.,

OCR for page 419
425 TABLE lIII I-1 Contributions of Various Characteristics of Sound to Annoyancea Sound Characteristic Steady hig}~-pitched sounds Steady low-pitched sounds Int erm i ttent high-p i tched sound s Intermit tent low-pi tched sounds Loudnes s of sounds Suddennes s of sounds Feeling that a sound cannot be turned of f Feeling that a sound is unnecessary Feeli ng that a sound comes from a source of lit tie benefit Sounds that clash (unharmonious ~ Sounds that catch one 's attention at a di stance and then ge t louder and louder Sound i s man-made aData from Dunn. 23 Relative Annoyance ~ Scale Value 3 e 94 Be 66 4e 54 Be 81 Be 46 5e 80 5e 55 5e 38 4 e 81 4e 43 5e 23 5e 65

OCR for page 419
426 TABLE VIII-2 Suggested Maximal Tolerable Intensities in Various Indoor Locations for More or Less Continuous Noise between 7 a.m. and 10 p.m.a Type of Space B road cas t s tudi o Concert hall Legitimate Cheater ~ 500 seats5 no amplification) Music room Schoolroom (no amplification) Apartments, hotel As semb ly hal 1 Home Mot ion-pict ure theater Hospital Chur ch Courtroom Library Of f ice Exe cut ive Secretarial (mostly typing) Draf tiny Meeting room ~ sound amplification) Re tail s tore Restaurant aData f ram Kryter 3 Intensity, dB(A) 28 28 33 35 35 38 38 40 40 40 40 40 40 35 50 45 45 47 55 .

OCR for page 419
427 piecework ~ var fed 1 ittle, if at all, with thermal conditions (note, however, that workers were paid by the piece) . ~ ~ When given the opportunity to express an opinion, people will be consistent in their preference regarding environmental conditions. The Comfort vote. has 1 iteral meaning in research on thermal acceptability. It refers to a sub jective rating on a seven-point scale of comfort, on which the midpoint signifies thermal neutrality. A large body of research has made it possible to determine, by means of Comfort equations, ~ the combinations of several factors--notably air temperature, humidity, radiant temperature, air velocity, degree of activity, and type of clothing--that will minimize discomfort. The range of acceptable combinations of environmental conditions Is known as the Comfort zone. Figure VIII-1 depicts summer and winter comfort zones adopted in 1981 by The American Society of Heating, Refrigerating, and Air~Conditioning Engineers (ASHRAE) . 2 ~ A The comfort zones show the relationship of comfort to temperature and humidity during ~light. activity. At least 809 of occupants should feel comfortable--no more than slightly warm or slightly cool--in these zones. The comfort zone is different between summer and winter, because people wear more clothing during the winter. The thermal resistance of a clothing ensemble can be measured precisely in Clog units . Table vIII-3 offer s an example of how a change in clothing will be reflected quantitatively in clo values and optimal operative temperatures. Operative temperature is determined on the basis of air temperature and average radiant temperature. In an interior zone with only a slight radiant component, the operative temperature approximately equals dry-bulb temperature. Insulation f rom slouching and degree of activity interact in determining acceptable temperature. The ASHRAE standard therefore offers an equation to convert acceptable operative temperature TIC) for sedentary occupancy (1 .2 mets ~ to that for Ire active occupancy (e . g ., housework at 2 mets , garage work at 3 mets ): to Active ~ = to~sedentary, - 3 (1 + clo) (met - 1.1), where to represents operative temperature. In addition to steady-state features of the thermal environment, the standard considers temporal nonuniformities (e.g., temperature cycling) and spatial nonuniformities (e.g., vertical temperature differences). Some limited nonuniformities, such as monotonic temperature drifts, may prove both economical and acceptable. ~ ~ Conditions for thermal comfort seem to vary little, if at all, with such factors as geographic location, sex, body build, ethnic background, and even age.24 The effects of aging seem to merit some special consideration. Basal metabolic rate decreases progressively with age, but, according to Fanger, 24 evaporative heat loss does, also. The two changes seem to of feet each other, although the elderly spend much more time than the young in sedentary activi ties . Furthermore, wi th the lower temperatures now common indoors dur ing winter, the elderly seem to have a narrower temperature range over which they can increase their thermal resistance. s 3 Because of sensory adaptation, a sedentary old person may fail to notice the symptoms of impending hypothermia until it becomes severe. Adequate

OCR for page 419
428 ~W w fir 50 at o 3 35 o 62.F;4 -15.C by/ ~~.~= . . ~ L~ ~ it/' _ He' 3~ hi, 2C, 25 ! I ~ ~ ~ ~ t t 80 fit ~ 0.0 IF ~0 OPERATIV TE MPE RAT UR E 0.01S O.OtO o - can - 0.005 ~ FIGURE VIII-l Acceptable ranges of operative temperature and humidity for persons wearing typical summer clothing and typical winter clothing. These "comfort zones" assume that occupants are engaged in only light activity. Reprinted with permission from American Society of Heating, Refrigerating, and Air-Conditioning Engineers.

OCR for page 419
429 TABLE VIII-3 l Temperatures for Thermal Acceptabili Icy (Comf art ~ o f Sedentary or Slightly Active Persons ( OCR for page 419
439 comparatively short time; particles smaller than 1 Um may remain suspended for hours, unless they become attached to other particles, walls, or surfaces. Dairies has reviewed deposition from moving aerosols. 22 Electrostatic and thermal precipitation are two important mechanisms by which particles are deposited. Penney and Ziesse47 have measured the nobilities of airborne dust particles under the influence of thermal and electrostatic gradients and have estimated an average effective thermal mobility of 2.4 x 10 8 m2/C.s and an effective electric mobility of about 11 x 10 8 m2/v m. These values can vary widely for different dust particles, but they are useful approximations for the design of dust-collecting equipment. Penney and Ziesse also noted that an electrostatic precipitator that does not capture all particles causes more soiling than an air-cleaner of the same efficiency that does not charge particles. Apparently, the particles become electrically charged, and that causes them to attach to surfaces more readily. Thus, it is important that the precipitator be des igned for maximal capture . The force of attraction between two molecules (London-Van der Waals force ~ varies as the inverse of the 7th power of the distance between them ~ ' and plays a role in interparticle adhesion or adhesion to surfaces. The electrostatic attraction of particles to surface. is very strong at distances of a few angstroms, but diminishes rapidly with increasing distance. From the standpoint of soiling, London-Van der Weals forces are probably important in particle retention after a particle contacts a surface. Corns' calculated the electrostatic attraction between a charged particle 1 ~ in diameter and an adhering particle or surface in which it induces an equal and opposite charge. Assuming a particle charge of 15 electrostatic units (e.s.u. --i.e., 15 x 10-9 coulombs--and a separation of 1 nm {10 Al, he estimated a force of 5.2 x 10-3 dynes, which is about 107 times the gravitational force, assuming a density of 1 g/cm3 . However, this is only one one-thousandth of the estimated Van der Waals force. Capillary attraction is a mechanism of particle retention due to adsorbed liquid f ilms . Capillary attraction is probably more important in fouling (where air comes into contact with damp coils or pipes) or in particle filtration (where adhesive liquids are applied to the filter} than in most everyday soiling of walls and surfaces. When the radius of the liquid film at the point of contact is small, compared with the radius of the particle, the force of attraction between a sphere and a plane surface, with a film of liquid interposed, may be expressed by the relationship ~ ~ 48yr, where ~ is the capillary force, ~ is the surface tension of the liquid, and r is the particle radius . 2 S Corn ~ ~ has suggested that that equation is approached only at relative humidities near 100%, where water is in the liquid phase. An lower vapor pressures, the force is less . The surface-to~volume relationship of particles increases dramatically an particles become very small, and this relationship za important in soiling. Surface force'; have a much greater role in determining soiling properties of small partic3 es than of larger

OCR for page 419
440 particles. Very fine particles cling to a glans slide when the elide is inverted. Walker and Fishy ~ demonstrated that repouring small particles by either liquids, airstreams, brushing, or gravity was more difficult than removing large particles. Human activities can cause agitation that resuspends de - sited particles. Primarily, it is the larger particles that are more readily redispersed by this means. Bunt, ~ ~ in experiments using a light- scatterinq-particle counter, showed that vacowe-cleaning a rug or operating an electric fan caused a severalfold increase in the number of particles larger than 3 ~m, but only a slight perturbation in the number of smaller particles. But other acti~ritie~--such as smoking, heating, or cooking--produced primarily submicrometer particles. Also, aerosols in this size range are probably produced by condensation from the vapor phase, rather than by dispersing preexisting particles from surfaces or from a powder. MOI STORE AND Ft3NGAL GROWTH Fungal growth is another cause of soiling and deterioration that generally occurs in areas with high humidity and low ventilation. Microbial slimes in air-cooling and -humidifying units, plumbing fixtures, condensation trays, and drains cause serious and often costly mechanical problems. These and other airborne organisms can discolor paint, weaken fabrics, and degrade foodstuffs. Microorganisms can also lead to odors, such as the musty smell of a damp bat. SchafferSS has reviewed many of the effects of moisture in buildings, including the promotion of fungal growth. Moisture can be generated internally from combustion during heating and cooking, drying clothes, bathing, and even breathing, and it can come from the outside during per iods of high humidity a Moisture generated indoors can result in high humidities when there is no dehumidification, when ventilation rates are low, or when a structure has tight vapor barriers in walls and partitions. Fungal growth in ducts or on walls and surfaces has been observed after the use of large amounts of outside sir for ventilation during damp periods. Water vapor is not ordinarily regarded as a pollutant. Not only is it essential to support the growth of microorganisms, but, if it in present in excessive amounts, it can cause more visible effects. such as peeling of paint and wallpaper. It also has an effect on comfort (as discussed earlier), and it can enhance the effect of other pollutant". Hermance et al., ~ for example, hare noted this in steadying damage to telephone contacts by airborne nitrates. GASEOUS POLLUTANTS The important gaseous pollutants--such as ozone, sulfur dioxide, oxides of nitrogen, and carbon monoxide--affect the corrosion and deterioration of materials. Ozone can cause cracking of rubber and some other elastomers. The amount or rate of cracking of stretched

OCR for page 419
441 rubber bands has been used as a method for determining low concentrations of ozone. 53 Not only does ozone occur in the outdoor air, but trace amounts Can be produced indoors by arcing of electric motors in tools and appliances and by corona discharges of electrostatic air-cleaners. Sulfur dioxide and oxides of nitrogen may also contribute to corrosion and deterioration, but they are more often considered as potential health hazards. Carbon monoxide is comparatively inert and does not react on surfaces; although it is a hazard to health and safety, i t does not normally cause soiling or deter "oration . EFFECTS OF TIGHT CONSTRUCTION . . . Reduc~cion of inf titration resulting from tighter construction decreases the amounts of pollutants coming from outside, but can cause increases in the concentrations of those generated indoors, unless there is a change in ventilation rate . To achieve the full benef it of t ight construction without increasing soiling, corrosion, and deterioration, provision must be made to abate or eliminate indoor- generated moisture and the indoor pollutants at their source. Particles and moisture are probably the most important agents that affect the rates of soiling, corrosion, and deterioration. Particle counts are usually lower indoors, 9 but not always. Cooking, cleaning, and other indoor activities intermittently distribute particles, as well as moisture . Sources of many other pollutants are discussed in Chapter IV. As mentioned earlier, increased tightness of buildings can result in increased moisture indoors. Previously, moisture generated indoors has leaked out through the building structure, but, as these paths of elimination are reduced, it may be necessary to use dehumidif iers . EFFECTS ON MAINTENANCE FOR CORROSION AND DETERIORATION Andrews S estimated that the cost of corrosion in the United States exceeds S25 billion per year. This expense is reported to be due to additional fuel, maintenance, or replacement costs. Although the f Faction of these costs caused by indoor pollution was not reported, it can be assumed that even a small percentage could represent a great f inancial impact over the lifetime of a building. Four types of corrosion, which must be controlled in building environmental control sys~cems, are shown in Table VIII-4, with some methods of prevention. ~ f the quality of the indoor a ir is degraded, the increased concentration of contaminants can aggravate scaling of heat-exchanger surfaces. s For example, the air in a space with relatively high moisture content often is recirculated across a cooling coil for dehumidifications Increased carbon dioxide and sulfur dioxide of the indoor air may react with the condensed water and accelerate corrosion on the cooling coil.

OCR for page 419
442 TABLE VIII~4 Types of Corrosion and Methods of Environmental Control in Buildingsa Type of Corrosion Resul t Maintenance Action Unifo rm Pitting Galvanic Direct chemical attack Local deposits of parti- cles on metal surfaces Electrochemical reaction between dissimilar metals ~ less noble metal is corroded ~ Stress Corrosion attacks stress- Replace weakened metal aData from And rews. Apply protective coatings Inspect and remove solid deposits Remove solids in suspension Apply such coatings as plastics, paints, and asphaltum (protect both metals with same material) Apply appropriate chemical inhibito ~ s

OCR for page 419
443 Report of increased maintenance of heat-exchangers or rotating equipment necessitated by degradation of indoor air quality were not found in the literature, but the appropriate conditions for increased corrosion have been reported. s ~. IS ~ ~ 47 IS For example, Her~nce et al. 3 reported that telephone switching equipment required increased maintenance because of nitrates. Inasmuch as nitrogen oxides and sulfur oxides can be present in indoor environments, either from indoor source. or from outdoors, the potential exists for corrosion of electric components in most indoor environments . EFFECTS ON HOUSEKEEPING . Cleaning and care of materials and properties in institutional spaces represent approximately 15-2096 of the total annual operating costs of these facilities (W. W. Whitman, personal communication). In turn, annual operating costs can be approximately 50-75% of the annualized initial investment of buildings.* Thus, any degradation of the indoor air quality that causes an increase in housekeeping can seriously affect the life-cycle cost of a building. As buildings have become more energy-efficient, the moisture content has been generally reported to have increased, owing to decreased infiltration. Is Additionally, the concentrations of smoke particles and other contaminants from smoking and other indoor activities have increased thee Chapter IV). Thus, the rates of soiling and deterioration of exposed surfaces may be accelerated. as a result of degradation of indoor air quality. Windows are a pr imary s ite for accelerated soiling, especially dur ing the heating season . Because resistance to heat transfer through windows is usually one-tenth to one-third that of adjacent walls, the inside surface temperatures of the windows will be much lower than those of the walls. I f the inside surface temperatures of the windows are lower than the dewpoint temperature of the occupied space, condensation will occur at these surface.. Particles and gaseous contaminants in equilibrium with the water vapor will be deposited on the window surfaces with the condensate. As the condensate leaves the windows by evaporation or draining, the other contaminants will be left on the surfaces as residue, thus increasing the required frequency of cleaning. Boyce~3 reported that, when windows are not thoroughly cleaned periodically, a cloudy film builds up that can be removed only with muriatic acid. To combat pollution in L;os Angeles, Boyce stated, aluminum mullions and transoms on the Con Park Plaza Building must be cleaned annually with mild steel wool and oil must then be applied to protect the metal . ~ f outdoor pollutants are transported indoors, or if similar pollutants are generated indoors, the interior surfaces of windows might require similar treatment. . *The annualized initial investment is based on a present cost of S70/ft2 amortized over 50 yr at an inflation rate of 9~. Current annual operating costs are approximately S3/ft2.

OCR for page 419
444 Indoor lighting efficiency is also affected by indoor air quality. Williams66 reported that dirt accumulations on lamps and fixtures can reduce light output by 10-50. over the rated ~end~of-life. of the lamps. Thus, as dirt and film accumulate on fixtures and lops, cleaning and relamping frequencies must be increased to maintain proper illumination . Another major category of housekeeping expense is related to the care of floors and carpeting. Darlings reported that, on a national average, 40-60% of the working hours of cleaning crew. is required for floors and carpeting and that carpeting soils more quickly in industrial centers than in suburban areas, where air pollution is lens severe. Furniture, paintings, sculptures, and musical instruments are also af fected by indoor air quality. The special requirements for environmental control in museum, art galleries, and auditoriums are indicative of the care that is required to protect these properties. ' METROS) OF TREATMENT There are ways to reduce the indoor pollution that causes soiling and deterioration . For example, sir f titration reduces the amount of ~ a irborne dust . Most central heating and air-conditioning systems contain air filters. Although these are usually not of high efficiency, they do reduce dust. An electronic a~r-cleaner designed for a specific system can remove still mare particles. The visible effects of undesirable thermal precipitation of dust on walls near grilles and radiators may be reduced by shields that direct air away from walls. Dehumidifiers remove excessive moisture. However, during the heating season, humidity is often low indoors, and it may be necessary to add moisture to the air, to prevent stress cracking in furniture and other wood products due to excessive drying. (The relationship between human comfort and humidity and temperature is discussed earlier in this chapter and in Chapter IV.) Tobacco-amoking places an added burden on a jr-cleaning and ventilation systems. In public buildings, smoking is often prohibited or restricted to specified areas. Particles and other airborne materials generated in cooking nay be largely repoured by exhaust systems near the point of generation. Activated carbon and other adsorbent air-cleanere are sometimes used in buildings in high-pollution areas to remove gaseous pollutants. However, these are not in general use, and they present some special problems. For example, it is harder to determine when an adsorbent filter needs to be changed than a particulate filter (see also Chapter ~X). RECOMMENDATI ONS Some of the commonly recognized agents that produce soiling and deterioration have been discussed in the foregoing paragraphs, but

OCR for page 419
445 additional questions need investigation. With regard to removal of indoor particles, where is the point of diminishing returns in improving the eff iciency of particulate f ilters? Likewise, where is the point of diminishing returns reached in increasing the rate at which air is removed from an occupied space and filtered? Dust composition may also be important. There have been a few analyses of indoor dust, 2 ~ ~ ~ but much less work that has tried to relate soiling, corrosion, or other deleterious effects to dust composition and particle size. Thus, the effectiveness of dust removal technology and the specific nature of the dust, as they relate to soiling and deter ioration, need f urther investigation. Information on the role of gaseous pollutants in soiling or corrosion is lacking. REFERENCES American Society of Heating, Ref. rigerating and Air~Conditioning Engineers. Symposium Bulletin. Air Conditioning Criteria for Man's Living Environment, Louisville, Kentucky, June 24-28, 1973. New York: American Society of Heating, Refrigerating and Air- Conditioning Engineers, Inc., 1973. .33 pp. 2. American Society of Heating, Refrigerating and Air-Conditioning Engineers. ASEIRAE Draft Standard 55-74R. Thermal Environmental Conditions for Human Occupancy. New York: American Society of Heating, Refrigerating and Air~ond~tioning Engineers, Inc., April 198 0 . 3. American Society of Heating, Refrigerating and Air~onditioning Engineers. Commercial and public buildings, pp. 3 .1-3 . 16. In ASHRAE Handbook and Product Directory. 1978 Applications. New York: American Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc., 1978. 4. Andersen, I. Formaldehyde In the indoor environment--Health implications and the setting of standards, pp. 65-77, and discussion, pp. 77-87. In P. O. Fanger and O. V1 bjorn, EdS. Indoor Climate. Effects on Human Comfort, Performance, and Health in Residential, Commercial, and Light-Industry Buildings. Proceedings of the First International Indoor Climate Symposium, Copenhagen, August 30-September 1, 1978. Copenhagen: Danish Building Research Institute, 1979. 5. Andrews, F. T. Building Mechanical Systems, pp. 117-124. New York: McGraw-Hill Book Company, 1977. 6. Arguelles, A. E., D. Ibeas, J. P. Ottone, and M. Chekherdemian. Pituitary-adrenal stimulation by sound of different frequencies. J. Clin. Endocrinol. Me tab. 22: 846-852, 1962. Austin, P. R., and S. W. Tzmmerman. Design and Operation of Clean }looms 1965, pp. 96-135. Birmingham, Mich.: Business News Publishing Company, I96 5. 8. Axelsen, O. Influence of heat exposure on productivity. Work Environ. Health 11:94-99, 1974.

OCR for page 419
446 A. Benson, F. B., J. J. Henderson, and D. E. Caldwell. Indoor-Outdoor Pollutant Relationabips: A Literature Review. U.S. Environmental Protection Agency (National Environmental Research Center ~ . Publication No. AP-112. Washington, D.C.: U.S. Government Printing Office, 1972. 73 pp. . Berglund, L. G. New horizons for 55-74: Implications for energy conservation and comfort. ASHRAE Trans. 86 (Pt. 13:507-515, 1980. 11. Berglund, L. G., and R. R. Gonzalez. Application of acceptable temperature drifts to built environments as a mode of energy conservation. ASHRAE Trans. 84 (Pt. 11:110-121, 1978. 12. Binder , R. E., C. A. Mitchell, H. R. Hosein, and A. Bouhuys . Importance of the indoor environment in air pollution exposure. Arch . Environ . Health 31: 277-279, 1976. 13. Boyce, S. Reflections on a clean glass building, pp. 36-37. In Maintenance Guide for Commercial Buildings. Cedar Rapids: Stamats Publishing Co., 1975. 14. Bradley, E. C., and A. J. Haagen-Smit. The application of rubber in the quantitative determination of ozone. rubber Chem. Technol. 24: 750-755, 1951. 15. Broadbent, D. E. Noise in relation to annoyance, performance, and mental health. J. Acoustical Soc. America 68 :15-17, 1980. 16. Cain, W. S. Contribution of the trigeminal nerve to perceived odor magnitude. Ann. N.Y. Acad. Sci . 237: 28-34, 1974 . 17. Cain, W. S. Lability of odor pleasantness, pp. 303-315. In J. H. A. Kroeze, Ed. Preference Behaviour and Chemoreception. London: Information Retrieval Ltd., 1979. 18. Cain, W. S., L. G. Berglund, R. A. Duffee, and A. Turk. Ventilation and odor control: Prospects for energy ef f iciency . Lawrence Ber keley Laboratory Repor t IL-9578 . Berkeley , Cal .: Lawrence Berkeley Laboratory, Energy and Environment Division, 1979. 61 pp. 19 . Corn, M. Adhesion of particles, pp. 359-392 . In C. N. Davies, Ed. Aerosol Science. New York: Academic Press, Inc., 1966 0 20 . Daises , R. H., D. W. Smith , A. Feliciano, and J. R. Trout. Air levels of lead inside and outride of homes. Ind. Med. 41~10) :26-28, 1972. _. Darling, W. E. A lot more of what you 're looking for on carpet care, pp. 22-25. In Maintenance Guide for Commercial Buildings. Cedar Rapids, Iowa: Stamats Publishing Company, 1975. 22. Davies, C. N. Deposition from moving aerosols, pp. 393-446. In C. N. Davies, Ed. Aerosol Science. New York: Academic Press, Inc., 1966. 2 3 . Dunn, B . E . The noise environment of man, pp. 193-257. In H. W. Jones, Ed. Noise in the Human Environment. Vol. 2. Edmonton, Alberta: Environment Council of Alberta, 1979. 24. Fanger, P. 0. Thermal Comfort. Analysis and Applications in Environmental Engineering. Copenhagen: Danish Technical Press, 1972. 244 pp. 25. Fuchs, N. A. The Mechanics of Aerosols, p. 362. New York: Pergamon Press, 1964. 26. Geber, W. F., T. A. Anderson, and B. Van Dyne. Physiologic responses of the albino rat to chronic noise stress. Arch. Environ. Health 12:751-754, 1966.

OCR for page 419
447 27. Geen, R. G., and E. C. Ordeal. Activation of cue-elicited aggression by general arousal. J. Personality Sac. Paychol. 11: 289-292, 1969 . 2 8 . Gieseke, J. A., E. R. glosser , and R. B. Reif . Collection and characterization of airborne particulate matter in buildings ASHRAE Trans. 84 (Pt. 1) :572-589, 1978. 29 . Glans, D. C., and J. E. Singer. Urban Stress. Experiments on Noise and Social Stressors. New York: Academic Press, Inc., 1972. 182 pp. 30 . Hermance, H. W., C. A. Russell, E. J . Bauer, T. F. Egan, and }I. V. Wadlow. Relation of airborne nitrate to telephone equipment damage. Environ . Sci . Technol . 5: 781-785, 1971. 31. Hunt, C. M. Simple Observations of Some Common Indoor Activities ss Producers of Airborne Particulates. Paper presented at ASHRAE Symposium on Cleaner Indoor Air--Progress and Problems Cl-72-1, Cincinnati, Ohio, October 19-22, 1972. 3 2. Jovanovi6, U. J. Normal Sleep in Man. An Experimental Contribution to Our Knowledge of the Phenomenology of Sleep. Stuttgart: Hippokrates Verlag Gmblt., 1971. 327 pp. 33. Kasl, S. V. The effects of the residential environment on health and behavior : A review, pp. 65-127. In L. E. Hinkle, Jr., and W. C. I`oring, Eds. The Effect of the Man-Made Environment on Bealth and Behavior . DREW Publication No. (CDC) 77-8318 . U. S. Department of Health, Education, and Welfare, Center for Disease Control. Washington, O.C.: U.S. Government Printing Office, 1977. 34 e Kryter, K . D. The Ef feats of Noise on Man . New York: Academic Press, Inc., 1970. 633 pp. 35. Lebowitz, M. D. A critical examination of factorial ecology and social area analysis for epidemiological research. Ariz. Acad. Sci. 1 2 (2~: 86-90, 1977. 3 6 . Lebowitz, [M. ~ D. Social environment and health. Public Bealth Rev. 4: 327-351, 1975. 37. Lebowitz, M. D. The relationship of socio-environmental factors to the prevalence of obstructive lung diseases and ocher chronic conditions . J. Chron. Dis . 30: 599-611, 1977. 38 . Lehmann , (;., and J . Tamm. t3ber Vertinderungen der Rreislaufdynamik des rohenden Menschen unter Einwirkung van Gerauschen. Int. Z. Angew. Physiol. einschl. Arbeitsphysiol. 16: 217-227, 1956. (in Ge rman ~ 3 9 . Lennard-Jone~, J . E . Cohes ion . Proc . Phys ical Soc . (London ) 43: 461-482, 1931. 4 0. Lin-Fu, J. S. Vulnerability of children to lead exposure and toxicity (First of two parts ~ . N. Eng1 . J . Med . 289 :1229-1233, 1973 . 4 1. Mathews , X. E., Jr ., and L. K. Canon. Environmental noise level as a determinant of helping behavior. J. Personality Soc. Psychol. 3 2: 511-577, 1975. 4 2. McNall, P. E., Jr . The relation of thermal comfort to learning and performance : A state~of-the-art report. ASHRAE Trans. 85 {Pt. 1), 7 59-767, 1979. 4 3 . Moschandreas , D. J ., J. W. Winchester , J. W. Nelson, and R. M. Burton. Fine particle residential indoor air pollution. Atone. Environ. 13 :1413-1418, 1;979.

OCR for page 419
~8 44. National Center for Bealth Statistice. Medical Care, Bealth Status and Family Income. Series 10, - . 9. Washington , D.C.: U.S. Government Pr inting Of f ice, 1964. Hemecek, J., and E:. Grand dean . Results of an ergonomic investigation of large~space offices. muon Factors 15:111-124, 1973. 46. New York S"te Commission on ventilation. Ventilation. Hew York: Du~cton, 19 23 . 47. Penney, G. W., and N. G. Zlesse. Soiling of surfaces by fine particles. ASEiRAE Transe 74{Pt. 11:vI.3.1-VI.3.13, 1968. 48. Pepler, R. D. A study of productivity and abeenteeism in an apparel factory with and without sir conditioning. ASERAE Trane. 79lPt. 2} s81-86. 1973. 49. Pepler, R. D., and R. B. Wamer. Temperature sad learning: An experimental study. ASHORE Trans. 74{Pt. 2)s211, 1968. 50. Prosbansky, B. M., W. a. Tttelson, and L`. G. RivItn. The influence of the physical environment on behaviors Some basic assumptions, pp. 27-37. In B. M. Proshanaky, W. B. Ittelson, and L. G. Riming Ede. Environmental Psychology: Man and Bis Physical Setting. New York: Belt, Rinehart and Winston, Inc., 1970. 51. Redford, E. P. Bealth aspects of housing. J. Occup. Hed. 18: 105-108, 1976. 52. Russell, F. A. R. The Ataospbere in Relation to fin Life and Health. Publication No. 1072. Washington, D.C.: Smithsonian Institution, 1896. Compiled in Smithsonian Misc. collections 39:Article ITI, 1899. 148 pp. 53. Sacber, G. A. Energy metabolism and tbermoregulation in old age. ASBRAE Trans. 85tPt. 1) :775-783, 1979. 5 4. Schaefer , v. J., V. A. Mohnen , and v. R. Heirs . Air quality of American homes. Science 175 :173-175, 1972. 55. Schaffer, }3. die A survey of some moisture and other problems influenced b`< building tightness. ASTM-DOE Symposium on Air Infiltration and Air Change Rate Measurement, Washington, D.C., March 16, 1978 (in prese). 56. Schaplowsky, A. F., L. G. Polk, F. 8. Ogleabay, J. B. ISorrison, R. E. Gallagher, and W. Berman. Carbon monoxide contamination of the living environment: A national survey of home air specimens and children's blood samples. Presented at American Public Health Association Meeting, November 7, 1973. U.S. Deparmen~c of Bealth, Education, and Welfare, Center for Disease Control. 57. Selye, B. One Stress of Life. rev. ed. New York: McGraw-Eill Book Company, Inc., 1976. 516 pp. 58. Speal~n, C. R. Odors, odorants, and deodorants in aviation. Ann. N. Y. Acad . Sci . 58: 40-43, 1954. 59. Spivey, G. M., and E. P. Radford. Inner~city housing and respiratory disease in children: A pilot study. Arch. Environ. Bealeb 34 s 23-29, 1979. 60. Sterling, T. D., and D. M. Robaysshi. Exposure to pollutants in enclosed slicing Spaces. ~ Environ. Res. 13s1-3S. 1977.

OCR for page 419
449 61. U.S. Depart~nt of Bealth, Education, and Welfare, National Institute for Occupational Safety and Bealth. National Occupational Hazard Survey. Pilot Study. Dow (NTOSH} Publication No. 75-162. Washington, D.C.: U.S. Department of Bealth, Education, and Welfare, May 197S. 62. U.S. Environmental Protection Agency, Office of Noise Abatement and Control. Information on l~evele of Environmental Noise Requisite to protect R,blic Bealth and Welfare with an Adequate Margin of Safety. U.S. Environmental Protection Agency B - port No. 5 50/9-74-004. Washington , D. C.: U. S. Environmental Protection Agency, 1974. 46 pp. ~ appendices. 63. Vega, T., and C. J. Seymour. ~ simplified method for determining ozone levels in community air pollution surveys. J. Air Po3~1ut. Control Assoc. 11:28-33,44, 1961. 64. Walker, R. L., and B. R. Fish. Adhesion of Particles to Surfaces in Liquid and Gaseous Environ~nente. Paper presented at 4th Annual Meeting of the American Association for Contamination Control, Miami, Fla., May 25-28, 1965. 65. Williams, H. Developing a table of relaxation allowances. Ind. Eng. 5~12) :18-22, 1973. 66. Williams, B. G. More light with less manpower, pp. 56-68. In Maintenance Guide for Commercial Buildings. Cedar Spider Stamats Publishing Co;, 1975. 67. Wilner, R., R. Walkey, T. Pinkerton, and M. Tayback. The Musing Environment and Family Life. Baltimore: me Johns Bopkins Press, 1962. 338 pp. 6 8. Winneke, G., and J. Ra~tka . Odor pollution and odor annoyance reactions in industrial areas of the Rhine-Ruhr region, pp. 471-479. In J. Le Magnen and P. Hack, ode. Proceedings of the Sixth International Symposium on Olfaction and Taste. tendons Information Retrieval Ltd., 1977. 69. W`nnick, L. American musing and Its Use s The Demand for Shelter Space. Census Monograph Series. New York: John Wiley ~ Sons, Inc., 1957. 143 pp. 70. Winslow, C.-E. A. Fresh Air and Ventilation. New York: B. P. Dut ton & Company, 1926. 182pp. 71. Winslow, C.-E. A., and L. P. Berr$ngton. The influence of odor upon appetite. Aaa. J. Hyg. 23:143-156, 1936. . World Bealth Organization. Health Bazards of the Busasn Environment. Genera: World Bealth Organization, 1972. 387 pp. 7 3. Wyon, D. P. Human productivity in thermal environments between 6SF and 85F (18-30C), pp. 192-216. In J. A. J. Stolwijk, Ed. Energy Conservation Strategies in Buildings. New Barren s John B. Pierce Foundation of Connecticut, Inc., 1978. 7 4 e Wyon, D. P. me role of the environment in buildings today s Thermal aspects. Factors affecting the choice of ~ suitable room temperature. Build Int. 6: 39-54, 1973.