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v FACTORS THAT INFLUENCE EXPOSURE TO INDOOR ATR POLLUTANTS The types and quantities of pollutants found indoors vary temporally and spatially. Depending on the type of pollutant and its sources, sinks, and mixing conditions, its concentration can vary by a factor of 10 or more, even within a small area. Human mobility constitutes an important kind of complexity in the determination of exposure to air pollutants. Human activity patterns differ between midweek and weekend, between one season and another, and between one part of one's lifetime and another. Activity patterns determine when and how long one is exposed to both indoor and outdoor pollutants. Therefore, in reviewing the factors that influence _ . . . . . . . . a 1r-pollut~on exposures, we have specif ically separated them into two major components: time (activity) and concentration (location}. Information on the time spent in various activities is summarized f irst, and then the variations In concentration encountered in different locations. Unfortunately, most of the -studies discussed were not longitudinal and thus do not offer information on seasonal ; d ifferences in time spent indoors and outdoors or on regional differences in activity patterns. Outdoor concentrations of pollutants and rates of inf titration affect the concentrations to which people are exposed indoors. The emphas is of the second section of this chapter is on geographic vat iations in outdoor pollution and their impact on indoor pollution . Building construction techniques, as they vary geographically, and their of feet on pollution inf titration rates are particularly important. But the measurement techniques available are ~ imited; the need for additional studies is discussed. The rates of inf iltration on a neighborhood scale have been studied by only a few researchers. Although their work has focused on energy conservation, their findings can easily be applied to the study of the impact on indoor pollution. As shown in Chapter IV, there can be large indoor-outdoor differences in pollutant concentrations. Concentrations also vary among indoor locations and from one time to another. In determining total exposure to pollutants, therefore, both indoor and outdoor concentrations must be well characterized. The ways in which building characteristics affect indoor pollution vary with type of pollutant, 225

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226 type of building, building location and orientation, and even room use within a given building. Building characteristics are the subject of the f inal section of this chapter . RtMAN ACTIVITIES Patterns of human behavior and activity determine the time spent in any specific location, and thus knowlege of them is essential in estimating exposures of populations to pollutants. As indicated by Ott, s ~ a large number and variety of studies in which data on human activities were collected from population samples have been completed over the last 50 yr. When one examines the literature on human activities, the term "time budget. (.zeitbudget,~ Budget de tempt is encountered often. A time budget produces a systematic record of how time is spent by a person in some specified period, usually 24 h. It contains considerable detail on a person's activities, including the locations in which the activities take place. One way of obtaining time budget information f rom the populations surveyed is to ask each respondent to maintain a diary of his or her activities over a 24-h period or longer. In another approach, the so-called ~yesterday. survey approach, the interviewer asks each respondent about his or her activities on the preceding day. Several summer ies of the Hilton ical development of time-budge t research have been published. ~ ~ ~ ~ s 2 7 ° Ott S ~ discussed the literature on activity patterns in the context of estimation of exposure to air pollution. The Multinational Comparative Time Budget Research Project, launched in September 1964 by a small group of social scientists from eastern and western countries, used common principles for sampling, interviewing, and data coding and tabulation on an international basis . The population sample consisted of nearly 30, 000 persons in 12 countries (Belgium, Bulgaria, Czechoslovakia, France, East Germany, West Germany, Hungary, Peru, Poland, United States, Soviet Union, and Yugoslavia). A standardized coding sytem was developed for comparing activities in different countries. The multinational study developed coding system with 100 categories of activities represented by a two-digit code (from 00 to 99~. The activities represented by these codes can be grouped into 10 classes: working time and activities related to work, domestic house work, care of children, purchasing of goods and services, private needs (such as meals and sleep), adult education and professional training, civic and collective participation, sports and active leisure, passive leisure, and spectacles, entertainment, and &ocis1 life. .' The Project yielded a rich data base that has been summarized in a number of tables, figures, and artic].es. 6t For example, the average time spent by employed men, employed women, and married housewives in var ious locations in 12 countries is shown in Table V-1 . The data show that employed men in the 12 counts ies spend between 12 h ~ in Hungary and 15 .2 h ~ in Belgiu - ) in tbeir homes, whereas housewives spend

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227 TABLE V-1 Time Spent in Various Locations in 12 Countries (Average Hours per Day ja . ,— . ~ _ Y ., . _ .. - E _ _ _ .. l ~ 1.1 E~by" ~. all - , s ins,*ones home IS.2 I2.S 143 136 13.6 14.~ 138 12t, 12.41 1*t(t 13.4 13.6 134 '~u I jn us' outs~r one's t~0mc (~.t (' ~ 0.3 0.3 1.0 O.t 0 4 1 f' f' 1 n ~ o.' o 1 t' ~ ~,.< atone'`workptace S.O 77 S.9 7.2 S.4 4.1 6.g 7.S 64 7.0 67 b5 6.S ~ srans'1 1.S 2.1 1.6 I.S 1 7 2.2 1 ~ 2.0 2.S 1.7 1.6 1.< .,, ! R v, othe'"ople's home O.S 0.2 0.3 O.S O.S 0.6 (~.3 (~.3 O.S 0.4 tI.4 0.6 (., (,, ~ ~ pl~esof buaness 0.7 0.6 0.6 O.S 0.4 0.4 t\.~ 0.4 0.? 0.4 ~ 7 0 7 ~ ~ O.S t'.< a, res"~ants end "rs 0.2 0.0 0.1 0.2 0.5 0.4 U 1 ().2 0.3 0 0 0.4 t3.4 0.2 `' ~ r'`' - allo~crhcat~ons 0.4, 0.2 0.9 0.2 0.9 0.6 0.3 0.6 0.6 0.' O.S 0.4 0.' ~ 3 U.1 toul 24.0 24.0 24.0 24~.0 24.0 24.0 24.0 24.() 24.0 24.0 24.0 24.0 24.0 ,4.D 24. 7 J. ~ t~po~t wo~. aN ^ws ms~c or~e sh~ 17.1 14.e 16.0 IS.3 17.0 16.7 16.7 14.S 16.1 IS.O IS ~ Ic ~ 14.0 15 (' 1S O ust outs~e one s home 0.1 0.3 0.' 0.0 0.7 0.2 0.2 0.3 1).4 0.1 0.0 ().1 Q.l t).3 ~t at one s wo?lcpbec 3.6 6.S S.1 6.3 3.6 3.6 4.9 6.8 4.4 S 8 S.2 S.(' t.7 ,,. ~ h sran512 }.' 1.6 1.3 1.} 1.1 1.3 1.1 1.4 1.8 I.S 1.3 1.3 1.7 1.4 ~ c c'~er people's home O.4 0.2 0.2 O.S t,.4 0.9 0.2 0.3 0.3 0.6 0 7 0.h D.2 0.6 0.2 ~ pl~s of buS~s5 1.0 0.6 Q8 0.6 0.6 (~.8 0.7 O.S 0.7 0.8 0.9 1.1 O.h 0 ~ O.4 u~re'"urantsandbsrs 0.2 0.0 0.0 0.1 0.~ 0.3 0.1 00 0.1 0.0 0.2 0.2 0.' V0 0.0 ~n ~! other bcai'ons 0.4 0.2 0.4 O. 1 ().4 0.2 0.1 0.2 O.2 0.2 0.3 0.d t).4 0. ~ t,. i to - 1 24.0 24.0 24.0 24.0 24.0 24.(1 24.0 24.0 24.0 '4.0 24.0 24.(J 24.0 24.0 24.u ~1.3 Ho-~. aU ~ys t~ °~J msidco~v'sl~e 21.6 20.4 20.9 21.7 20.4 20.S 21.3 197 '1.0 20.9 20.S '119 19.6 205 19., JUst outs.,c one's hon" 0.2 1.4 0.3 ().1 0.8 0.4 0.3 2.! O.S 0. t 0.1 0.1 (` ~ O ~ 2 - ~an~t 1.0 O.9 1.: I.0 1.0 1.0 1.0 0.9 1.2 1.2 1.0 0.9 1 ~ 1 ~ 1 1 other people's t~ome 0.4 0 4 0 3 O.S 1~.6 O.6 0.) 0.2 0.4 t1.S 0.8 0.7 0. . ti ~ `i ~ mpbmsotb~ncss O.S 0.7 1.1 0.6 0.7 1.1 0.9 0.9 0.? 1.' 1.2 1.1 1.1 n.4 O.S ~n tcsr-urmts end bus O.J 0.1 0.0 (~.~) 0.1 0.1 0.U 0.0 0.0 0.0 0.] (~1 0.(' (~.(i (~.D o~e'toesuons 0.2 0.1 0.2 0.1 0.4 0.3 0.2 0.2 0.2 0.1 0.3 0., 0 ~ ~ 1 ().1 toul 24.0 24.0 24.0 24.0 24.0 24.0 24.(} 24.0 24.0 24.0 24.D 2<.0 24.0 '4.0 24 - aReprinted with permission from Szalai.69 Data are weighted to ensure equality of days of the week and number of eligible respondents per househol d.

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228 between 19.7 h (in Hungary) and 21.6 h (in Belgium} in their homes. In the 12 countries, therefore, employed men spend, on the average, 50-63t of the day in their homes, and housewives spend 82-901 of the day in their homes. It is difficult to determine the overall amount of time spent indoors from these data, because categories like Hat one's workplace. do not distinguish between indoor and outdoor workplaces. Similarly, the categories Sin places of business. and tin all other locations. do not specify whether they are indoors or outdoors. However, if one assumes that all ~workplaces,. replaces of business,. and Restaurants and bars. are indoors, along with the category tin other person's hones,. and that the category Sin all other locations. is assumed to be entirely outdoors, then it is possible to estimate the amount of time spent by respondents in three general categories: indoors, outdoors, and in transit (see Table v-2~.Si Wi th these assumptions and the restructured data shown in Table V-2, it is estimated that employed men in the 12 countries spend between 84% ~ in Maribor, Yugoslavia) and 92% ~ in France) indoors . It should be emphasized, however, that many of the entries in Table V-2 cannot be compared with each other on a statistical basis, because the numbers of respondents in the samples vary . Also, the representativeness varies, because some countries, such as the Soviet Union, are represented by a single city and its suburbs (Pskov, population 115, 000 ), whereas others , such as the United States (44 cities ), are represented by a national sample of metropolitan areas . Finally, some assumptions as to whether a location was indoors or outdoors need to be examined, because they may introduce error. However, the estimates in Table V-2 appear useful as rough approximations of the times spent by residents of 12 countries indoors, outdoors, and in transit. 5 ~ I f only the data for the United States {44 cities ~ are considered, it appears that, on the average, employed men spend 90% of the day (21.7 h) indoors, whereas married housewives spend 95% of the day ,~2.8 h ~ indoors . Employed men in the United States are estimated to spend 2 . 9 ~ of the day ~ 0 . 7 h ~ outdoors, and housewives 1 . 7 % (0 . 4 h ~ . Although the estimates in Tables V-1 and V-2 are useful for determining the total amount of time spent in various locations, they give little information about the time of day when persons are present in each location. Data from the multinational study can be displayed in a composite profile that shows the proportion of the population that are engaged during the day in selected activities, such as sleeping. eating, working, travel, and watching television {Figure it-l}. In addition to the studies of activities in the United States by Robinson, 57-55 activity-pattern studies have been carried out in Durham, N.C., by Chapin and Hightower, ~' on a sample of 43 Standard Metropolitan Statistical Areas (SMSAs) by Chapin and Brail, \2 on a followap U.S. national sample by Brail and Chapin. ~ and on the Washington, D.C., metropolitan area by Hammer and Chapin. ~ 2 Information supplied in this section is limited to urban areas; this reflects the available published information. No comments are made on variations in numbers, because it i'; beyond the scope of this document to assess their reliability.

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229 -'1 . ? · I =~=ol ~5 0 o 00 v _ S ~ ^ O ~ a: to - 3 CL in - C o an, owl c ~7 ~ C~ ~ ~ 0 ~ ~ I_ ~ · e ~ e e ~ e e e e e e e · e O O O O O O O O ~ O ~ O ~ O O L~ C~J ~J t~ '1 ~ 1—^1 ~ ~ ~ ~ ~ · e e e ~ e · · ~ e ~ e e e e O ~ O O ~ O O ~ O O ~ O O O e~ C~ ~ 0` ~ ~ O ~ ~ ~ e ~ e e e · ~ e ~ a ~ · · e e C~ C~ ~ ~ C~ ~ ~ ~ ~ C~ C~ ~ C~ C~ C~ ~ ~ ~ C~ C~ ~ ~ ~ C~ u~ _~ ~0 l~ 1~ ^1 ~~ O ~ 1~ ~D ~ O =) t~ · ~ e e ~ ~ · ~ e e e ~ ~ e e c~ ~ ~ ~ ~ ~ ~ c~ 0` ~ ~ ~ ~ ~ '_ ~ O · e e e e e e e e e e e a e O O ~ O ~ ~ O _ O O O O ~ O O ~ ~ ~ I_ ~ -;r ~ ~ ~ ~ O · e a e e e e ~ e e e ~ ~ e e ~ ~ ~ ~ O O ~ O O ~ ~ ~ ~ ~ O C~ ~ ~J C~ C~J ~ ~ ^1 ~ ~ ~ ~ e`' ~ ~ e e _h ~C 0 v ^ ~ V ~ ~= ~ ~ ~ ~= 0 V V V O ~ ~ 3 ~ O ~ 8 ~ ~ 0 _ a' ~ ^ V ~ O ~ ~J D ~ V ,~ ~ ~ _1 0 ~ ~ ^ O —~ O O ~ O C ~ O ~ 40 ~ D —~ _ _1 0 0 0 ~ ~ -~ ~ ClO— `: V ~ O X ~ —— {t ~ _t _'_-_~ - ~ O N _' ~ ~ ~ c: a, 0 ~ ~ ~: :^ >~ :^ 0 ~ ~ ~ ~ ~ _ _ ~ els X C ~ ~ ~ 1 ~ ~ v _ ~ ~ ~ ~ ~ ~ ~ 0 ~ a~ 0 0 ~ ~ ~_ ~ - ~ V ~ ~ c5 ~ _ ~ ~ ~ ~ _ cn u~ . :> :> :^ ~ ~ ~ ~ ~ ~ `= 0 ~ ~ ~ ~ ~ _= ~ ~ . S ~ ~ ~ ~ om ~ ~ o0 00 C) ~ ~ V V ~ ~ ~ ~ V · 0 0 ~ ~ ~ ~ ~ 0 ~ ~ ~ ~ ~ ~ _ O (V ~ N ~ ~ ~ ~ ~ ~ O ~ ~ · Z 3 3 ~ S ~ D o S ,~ O o5 a, v o ce - .~. c~ ~S N tn ~ - D 3 D C :^ ~ —~ 3 o v v O O :^ ~ C' - 4 ~ ~ O :> S~ :^ ~5 U~ ~ . ~? v C o O v ~0 3 :^ - O 0 0 C o 0 CL

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230 100 80 he G 60 - 40 20 ~ Sl - P I Work // ~ // {~/ / O ~1 1 1 1 it 0.00 2.00 4.00 6.00 8.00 10.00 12.00 2.00 4.00 6.00 8.00 1 0.00 12.00 MIDNIGHT 6 AM NOON 6 PM MIDNIGHT \ ,: / and Family~\ ~ ,~7'J,>? ;/~1~ Tdev''ion \\ TIME 4.00 6 00 FIGURE V-1 Diurnal profiles showing percentage of employed men in United States (44 cities ~ engaged in nine types of activities as a faction of time of day (weekdays only). Data weighted to ensure equality of days of the week and numbed of eligible respondents. Reprinted with permission from Szalai. 9

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231 In the United States, legislation passed in 1952 required urban areas to conduct metropolitan-area transportation studies as a prerequisite for receiving federal funds for highway construction. As a result, transportation studies have been undertaken in 200 areas of the United Stares, and these studies have usually involved collection of considerable detail about the transportation activities of the urban population, particularly in cities with populations in excess of 50,000. As reported by Robinson, Converse, and ssalai,6° the multinational research project also collected information on the average time spent in commuting to and from work in various countries (see Table V-31. Most of the summaries of findings from time-budget studies have presented only average values and seldom given histograms or information on the variance of the time spent in various locations or activities. In 1969-1970, the U.S. Department of Transportation made arrangements with the Bureau of the Census to carry out a nationwide study of the transportation-related activities of the U.S population. This study, called the Nationwide Personal Transportation Study, was based on home interviews and covered individual activities in considerable detail. ~ ~ ' 26 27 33 S. ~S-~. Figure V-2 shows a f requency distribution of the amount of time spent in commuting based on these data. Assuming two trips per day, the overall average of 22 min/trip compares reasonably well with the average of 46 min/d reported by Robinson, Converse, and Szalai . ' ° There is a need for a special-purpose activity-pattern study specifically tailored to the problem of estimating air-pollution exposures. Previous activity-pattern studies have not considered questions that apply to exposures to air pollutants. Such a survey should begin with a pilot study on a single city, to perfect the experimental design and data-collection methods, and should use personal monitoring instruments to measure exposures. Once the pilot study is completed and the results are evaluated, a large-scale research investigation could be cart fed out on a number of cities or on a national probability sample. The large-scale survey would use diaries and personal monitoring instruments to characterize the frequency distribution of air-pollution exposures of the population as a whole and in selected cities . Information f ram the diar ies could be compared with the measurements of exposure to determine how dif ferent activities affect population exposure rates. GEOGRAPHIC AND LOCAL VARIATIONS The air quality of an indoor environment is often described on the basis of one 24-h average obtained from one indoor sampling location. The spatial distribution of indoor air pollutants within a structure is a little-studied subject. Therefore, recent or current unpublished works and technical papers related to environmental concerns, but not nectar fly to indoor air quality, are incorporated in this review. Some of the associations made and conclusions reached are clearly based on explicitly stated assumptions, rather than on scientific documentation.

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233 .E o ~ . _ ~ - ~o _ . o o _ CD . _ an o _ - - - r. - ~0 CC} · · · · · - 1 ~ 1 1 1 ~ O ~ O ~ ~ ~ O ~ O SYOS`~` in lU33~& O ~ ~ E ._ - o D Cal C S4 CO ~0 1 ~ U. S ~ e o a o is? c to 0 0 Us x so v F; o v o v at o o ~ 3 ~ t o o 1 o A: o o 3 o CL 0 X`D ~ - _~ c: g C' _ ~ So U.

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234 The types of pollutants and the concentrations of each type vary between locations within a structure, between structures within a geographic area, and between geographic areas. This section discusses some of these interrelationships. GEOGRAPHIC V0IATIONS IN I~R AIR QUASI" Owing to the small number of field monitoring steadies, the geographic distribution of indoor air pollutants has not been determined. However, it is instructive to review the geographic distribution of the major factors that affect variations in the concentrations of pollutants and their impact on the quality of the indoor environment. Outdoor air quality, air-infiltration rates, and sources of emission of indoor pollutants are the major factors. Outdoor air quality has been studied with respect to some pollutants, and the gem raphic distribution of these few pollutants is well understood. Descriptive statistics published annually by EPA and state and local air~quality agencies furnish much scientific information useful in discerning regional and ~ ocal differences in concentrations of carbon monoxide, total suspended particles, ozone, NOk , sulfur dioxide, sulfates, and others. Clearly, it is beyond the scope of this document to summarize the existing information on geographic variations in the types and concentrations of all ambient pollutants. It should be noted that the geographic distribution of some criteria pollutants has been studied and is easily accessible from the literature; information on noncriteria pollutants is sparse and often collected and analyzed by questionable methods. Concentrations of chemically nonreactive pollutants in residences generally correlate with those outdoors. Results from the six-city study, " which monitored indoor and outdoor environments for an extended period, clearly showed the influence of outdoor concentrations on the indoor environments (see Figure V-33. Another study,., .' sponsored by EPA, supported the conjecture that indoor concentrations of inert gaseous contaminants correlate with outdoor concentrations. The available data base i" not large enough to support statistical conclusions, but there is little doubt that the variations in indoor pollutant concentrations correlate with variation" in outdoor concentrations. Thus, it is expected that a city with high outdoor pollutant concentrations will have high indoor concentrations, unless control strategies are used . Although this is a broad, general conclusion, it must be emphasized that the indoor concentration of ~ given pollutant is expected to vary widely among residences within one city. This variation may be sufficient to mask the impact of varying outdoor concentrations Distribution of indoor air quality is extremely difficult to describe on a geographic scale, because indoor air quality is determined by complex dynamic relationships that depend heavily on occupant activity and highly variable structural characteristics. Weather, which has a regional character, influences indoor air concentrations of some chemicals, such as formaldehyde, and biologic -

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235 ~0 NO2 60 '9~] SO 30 20 tO L: PORT. To ~G WA T. 1 1 1 ~ .. . s ~ id' . ST.L. 57EU. ~ Outdoor O ~ · - IN I ~ he ~ coo _ star d - ~~c cad - r FIGURE V-3 Annual nitrogen dioxide concentration outside and inside electric- and gas-cooking homes ~ averaged across each community' ~ indoor and outdoor network (May 1973-April 1978). Reprinted with permission from Spengler et al.6

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248 Pl]TSBURGH HIGH-RISE #3 171IJNE 77 TIME 1645 10— 9— 8— 7~ Hi_ 3~ 2— At o 10 ~ . . I I ~ _ _ = _ _ ___ _ _ _ . ~ ~1 1'''' . . === ' Z . === . _ ~— ~~ = , ~ . d: _m l 1 - . . i___ ___ 1 14 1 T . 1 . 6 1 1 , l l . , . . . : , . . ~ _ ~ 6- _ . __ it_ _ _ _ _ , a_ 4— 10 _ 1~1 . ==== . ==== _==== = = ===== , _j _ _ ~ ~ ~L~ ~ , Source . . 1 Lnr~ Roon ICitchcc Hen '. Ben o A.= _- : = ~ Marc' - . FIGURE V-8 Episodic release of sulfur hg~afluoride gas. Reprinted with permission from Moschandreas et al.

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249 building's service life. The relationship between building factors and indoor air quality teas not been quantified, or for that matter extensively studied, but it is important. Designing and controlling building factors may prove to be an effective mechanism for acbleving desirable indoor air quality. SITE CHARACTERISTICS The characteristics of a building site that influence indoor air quality are addressed as three related subjected air flow around buildings, proximity to major sources of outdoor pollution, and type Of utility service available. The air flow around a building has been shown to be determined by the local characteristics of the geometry of surrounding buildinqe. so the location and type of surrounding vegetation,7' the terrain, 22 and the size and shape of the building itself. 3i Pollutants can be transported by the air flow frown street level, over the facade of the building, and onto the roof. A 20 35 Field tests of isolated buildings have been reed to develop scaling coefficients for both isothermal and stratified cases of surface wind pressures, turbulence, and dispersion. t, s' Air flow around a building creates low pressure on the leeward "ice and/or the sides adjacent to the windward face, as well as the roof. 30 Air pollutants released from stacks, flues, vents, and cooling towers in the region can reenter the building through makeup-air intakes for ventilation. A Trees and forests have been generally studied as -helter belts in an agricultural context. Shelter belts affect, air flow around building.. When an air current reaches a shelter belt, part of it is deflected upward with only a slight change in velocity, part passes through the crowns of the trees with very low velocity, and part is deflected beneath the canopy with rapidly decreasing velocity. 2 ~ ~ ~ The changes ir, velocity of air flow outside may change the infiltration rate and thus affect indoor air quality. lithe location of a building relative to a major outdoor pollution source can affect indoor air quality. For example, buildings near major streets or highways often have high carbon monoxide and lead concentration., owing to the infiltration of tbese pollutants. 15 t. 23 The type of utility service available is also related to the siting of a building and may affect the character of its indoor environment. The availability of particular fuels (e.g., natural gas and oil) influences the types and concentrations of pollutants {e.g., combustion products) emitted by space- and water-heating. Service moratoria, development timing, and development scale are institutional elements that contribute to the variability of utility services and thus can affect indoor air quality. OCCUPANCY Occupancy factors that affect indoor air quality include the type and intensity of human activity, spatial characteristics of a given activity, and the operation schedule of a building .

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250 Several human activit$es--such as ~king, cleaning, and cooking--generate gaseous and particulate contaminants indoors. Tbe number of occupants of a space and the degree of their physical activity (i.e., metabolic: rate at rest or under intense activity} are related to the production of various pollutants, such as carbon d ioxide, water vapor, and biologic agents. If the only source of indoor carbon dioxide production is that caused by occupants, ventilation rater may be proportional to the number of people and their metabolic rates. Is Although studies have shown no constant ~ _ relationabip between carbon dioxide concentrations and the concentrations of other pollutants, carbon dioxide concentration is often used as a general indicator of the adequacy of ventilation in an occupied space. Building occupancy is often expressed as occupant density and the ratio of building volume to floor area. The importance of occupancy in indoor air quality is illustrated by the fact that the choice of natural or mechanical ventilation is based on occupant density and the spatial characteristics of the budding under consideration. The use of Yaglou's early work on the relationship between occupant density and detectable body odor in determining necessary ventilation rates is discussed elsewhere. Occupancy acbedules and associated building use may affect the type, concentration, and time and space distribution of indoor pollutants. Because most buildings are unoccupied for substantial portions of each day, the manipulation of Operating schedule. is a means of controlling energy use. ~ Efforts to conserve energy through the design of ventilation system can result in tbe degradation of indoor air quality. 55 However, detailed studies relating ventilation capacity, occupancy Schedules, energy reguirements. and indoor air quality bare only recently been implemented. DESIGN Elements of building design tbat affect the indoor environment include interior-space design (apace planning), envelope design, and selection of materials. The evolution of space planning in many building types has resulted in flexibility in assigning functions to specific locations. However, this flexibility is accompanied by a decrease in the ability to predict exposure to air pollutants. In particular, ~open-plan. offices and schools have serious technical problems of redundant service distribution, limited acoustic control, incomplete air diffusion, and incomplete pollutant dispersion indoors. compared with ~fixed-plan. floor layouts. Evaluation of the success of a floor plan in achieving space efficiency, structural economy, and energy efficiency is usually in terms of net area per occupant and ratio of net usable area to total area. Explicit planning for environmental quality must be included to ensure that spatial arrangements are acceptable to the occupants. A building's structural envelope consists of both primary elements--foundations, floors, walls, and roofs--and secondary ~skin.

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2S1 elements--facings, claddings, and sheathing. To various degrees, the function of these is to maintain the integrity of the structure under the stresses caused by structural load, wind pressure, thermal expansion, precipitation, earth movement, and fire. me integrity of the building envelope is a major consideration in uncontrolled air movement into and out of a building--usually referred to as ~infiltration. ~ This in a major factor in indoor air quality. There teas been no systematic survey of infiltration rates of buildings in the United States. The dominant factor in determining a building's infiltration rate is the total area of effective leakage, as measured with fan pressurization. Following the leakage area in importance are the terrain and shielding near the building, the mean climatic conditions during beating {or cooling) periods, and the building height.'2 There is muab evidence,)' both in the United States and in Europe, that house. in mild climates are Every leaky, ~ whereas houses in severe climate- are ~tight.. Greater height of a building increases the attack effect,. or updrafting, and exposes the building to higher wind speeds. lout, higher wind pressures drive air through existing openings, referred to as ~leakage,. increasing the infiltration rate. 62 The dominant building factor" that determine infiltration have not been identified, but a catalog of leakage openings found in typical structures z. as follows: · Walls: Leakage around sill plates (the opening. at the bottom of wallboard), electric outlets, plumbing penetrations, and headers in attics for both interior and exterior walls. · Windows and doors: Window type in more important than manufacturer in determining window leakage. " This source of leakage tends to be overrated; it contributes only about 20% of the total leakage of a house.' 7~ · FireDlaces: This includes damper-, glass screens, and fireplace caps. · Beating and cooling sY-~temB : The variables include combustion air for furnaces, dampers for stack air draft, air-conditioning units, and location of ductwork. · Vapor bar r ier and insulation penetrations . · Utility accesses: This includes recessed lighting and plumbing and electric penetrations leading to attic or outside. · Terminal devices in conditioned space: This includes leakage of dampers, especially those for large air-handling systems. · Structural types: Examples are drop ceilings above cupboards or bathtubs, prism-shaped enclosures over staircases in twos tory houses, and elevator and utility abafts that lead from basement to attic. Wall and ceiling materials and floor finishes are the constituents of the building interior. Modular components, weight, strength, thermal insulation, thermal stability, sound insulation, f ire resistance, ease and speed of installation, and ease of maintenance are among the criteria considered in the selection of materials for walls, ceilings, and floors. But emphasis on first cost, ease of installation, maintenance, and long service life has also led to the

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252 use of materials that may be sources of indoor contaminants, as mentioned in Chapter IV. OPERATIONS Depending on the type of ownership Owner Occupied or developer~owned}, building operation may vary considerably, and this variation may have an impact on indoor air quality. Building operation. pertains to the following elevate of a buildings the building envelope, service and plant, building facilities, equipment, and landscaping. Cleaning, preventive maintenance, and replacement and repair of defects are also included in building operation. ace staff responsible for building operation include ~nageaent, engineering, and custodial personnel. The care responsibilitiea are operation of the treating, ventilation, and air~conditioning systems and building services, such as hot water, lighting, and power distribution. Building operation has an impact on indoor air quality in numerous ways, but the magnitude of this impact is not know. SUMIARY AND R~BNDATIONS . . The nearness of ~ building to pollution sources and its orientation with respect to wind affect the impact of airborne pollutants ~ritbin its envelope and the performance of its OVAL: system. Air flow around buildings, protective building placement. and landscaping at the site and on an urban scale are useful in mitigating indoor contamination. The magnitude and duration of activity in a building affect the generation and dispersion of pollutants. Building classificatione that specify occupancy limits for safety and fire protection can also be used to determine its environmental Control reguireaente. The control of indoor pollutants depends on floor layout, pollutant concentrations. emission rates of Sources, and type of ventilation system. Theme factors vary with the age, region, and type of construction of the buildings. A systematic formulation of interactions of air turbulence, stratification, and pressure distribution between buildings needs '^5-ii,''' ~6 developed to predict the effect of site conditions and design a amputee for buildings. Also, obiecti~re aeasure~nte of concentrations of ~ . _ . . . . . _ contaminants for aaJor cla608 of builds - e now to be ~~e for use In predicting the effects of building factors on the requirements for pollution mitigation within buildinqe. The messure~nt of dispersion characteristice for basic floor layouts and sys tees should be undertaken to identify cathode of dilution or masking of pollutants. The manhunt of energy required for mitigation with various control strategies should be studied to optimize energy efficiency and indoor air quality. The lifetime costs of various mitigation strategies should be measured to identify promising first cost and annual~cost alternatives both for the design of new buildings and for the redesign of existing buildings.

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2S3 REFERE~:ES 5. 1. American Institute of Architects Research Corporation. Phase Two Report for the Development of Energy Performance Standards for New Buildings. Report to U.S. Department of Mousing and Urban Development and U.S. Department of Energy, 1979. 197 pp. 2 . American Society of Heating, Refrigerating and Air~Conditioning Engineers. ASHRAE Handbook of Fundamentals. New York: American Society of Beating, Refrigerating and Air~Conditioning Engineers, Inc., 1972. 688 pp. 3. Asin, R. B. Nationwide Personal Transportation Study. Purposes of Automobile Trip- and Travel. Report No. 10. Washington, D.C.: U.S. Department of Transportation, Federal Highway Administration, Office of Highway Planning, 1974. 99 Be. As in , R. H ., and P . V. Svercl . Nationwide Personal Transportation Study. Automobile Ownership. Report No. 11. Washington, D.C.: U.S. Department of Transportation, Federal Highway Administration, Of f ice of Highway Planning, 1974 . 7 4 pp . Bahnfleth, D. R., T. D. Mosley, and W. S. Harris. Measurement of infiltration in two residences. Part I: Technique and Measured infiltration. ASERAE Trans. 63:439-452, 1957. 6 . Beachen , D. A., Jr . Nationwide Personal Transportation Study . Transportation Character istics of School Children. Report No. 4 . Washington , D.C .: U.S . Department of Transportation , Federal Highway Administration, 1972. 32 pp. 7 . Blomsterberg, A. R., and D. T. Harr jet Approaches to evaluation of air infiltration energy losses in buildings. ASlIRAE Trans. 85 (Pt. 1): 797-815, 1979. 8. Brail, R. K., and F. S. Cbapin, Jr. Activity patterns of urban residents . Environ . Behav . 5 :163-191, 1973 . 9. Caffey, G. E. Residential air infiltration. ASHRAE Trans. 85(Pt. 1) :41-57, 1979. . Cermak, J. E. Nature of air flow around buildings. ASHRAE Trans. 82 (Pt. 11:1044-1054, 1976. 1 1. Chapin , ~ . S. ., Jr . Buman Activity Patterns in the Ci ty : Th ingot People Do in Time and in Space. New York: John Wiley & Sons, Inc., 1974. 272 pp. 12. Chapin, F. S., Jr., and R. R. Brail. Human activity system in the metropolitan United States . Environ. Behav. 1 :107-130, 1969. 1 3 . Chapin, F. S ., Jr ., and ~ . C . Hightower . Bousehold activity patterns and land use. J. Am. Inst. Planners 31~3) :222-231, 1965. 14. Coblentz, C. W., and P. R. Achenbach. Field measurements of air infiltration in ten electrically-heated houses. ASHRAE Trans. 6 9: 358-365 , 1963 . 1 5 . Cohen , A . S ., and EC . Granauf . Summary and Conclus ions : Carbon Monoxide Monitoring Programed, Haper`?ille, Illinois. Technical Report of the Environmental Pollutants and the Urban }economy Project . Argonne , Ill .: Argonne National Laboratory, 1974 . 1 6. Converse, P . E. Time budgets. pp. 42-47. In D. L. Sills, Ed. International Encyclopedia of the Social Sciences. Vol. 16. New York: The Macmillan Company and the Free Press, 1968. /

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254 17. Davenport, A. G. A rationale for determination of design wind velocities. Proceedings of the ASCE Journal of the Structures Division 86:39-66, 1960. 18. Department of Environmental Control, Chicago. Indoor-Outdoor Carbon Monoxide Concentration Survey within the City of Chicago,. Central Business District. Chicago: Department of Environmental Control, 1973. 19. Dickerhoff, D., D. T. Grinarud, and B. Shohl. Infiltration and Air Conditioning: A Case Study. Lawrence Berkeley Laboratory-Report LBL~11674 . Berkeley , Cal .: Lawrence Berkeley Laboratory, 1980 . 20. Evans, B. H. Natural Air Flow around Buildings. Texas Engineering Exper imental Station Research Report 59, College Station, Texas, 1957. 21~. Federer, C. A. Effect of trees in modifying urban microclimate, pp. 23-28. In S. Little, and J. H. Noyes, Eds. Trees and Forests in an Urbanizing Environment. Amherst, Mass .: University of Massachusetts Cooperative Extension Service, 1971. Geiger, R. The Climate near the Ground. Cambridge, Mass.: Harvard University Press, 1965. 611 pp. 23. General Electric Company. Final Report on Study of Air Pollution Aspects of Various Roadway Configurations. New York: New York City Department of Air Resources, 1971. 24 0 General Electr ic Company . Indoor-Outdoor Carbon Monoxide Pollution Study. U.S. Environmental Protection Agency Report No. EPA-R4-73-020 . Washington, D.C.: U.S . Government Printing Off ice , 1973. [448] pp. 2S. Gibson, U. E., and R. E. Cawley. ],Ae heat pump solar collector interface--A practical experiment. Appliance 13ng. 11~4~:68-71, 1977. 26. Gish, R. E. Nationwide Transportation Study. Charac~ceristice of Licensed Drivers . Report No . 6 . Washington , D.C.: U. S . Department of Transportation, Federal Highway Administration, Of f ice of Highway Planning, 1973. 36 pp. 27. Goley, B. T., G. Brown, and E. Samson. Nationwide Personal Transportation Study. Bousehold Travel in the United States. Report No. 7. Washington, D.C.: U.S. Department of Transportation, Federal Highway Administration, Office of Mighway Planning, 1972. 40 pp. 28. Grot, R. A. A Low-Cost Method for Measuring Air Infiltration Rates in a Large Sample of Dwellings. National Bureau of Standards Report No. NBSIR 79-1728. Washington, D.C.: U.S. Department of Commerce. National Bureau of Standards, 1979. 10 pp. 29. Grot, R. A., and R. E. Clark. Air I,eakage Charscteristice and Weatherization Techniques for L^w-Incon~e Bou';ing. Presented at DOE/AS Conference on Thermal Performance of Exterior Envelopes of Buildings, Orlando, Flor Ida, December, 1979 . 30. Halitsky, J. Air flow and pressures near exterior building surfaces. ASHRAE J. 7~73:37-38, 1965. 31. Halitsky, J. Gas diffusion near buildings. ASERAE Trans. 69: 464-484, 1963. 32. Hardener, P. G., Jr., and F. S. Chapin, Jr. Human Time Allocation: A Case Study of Washington, D.C. Technical Monograph. Chapel Hill: University of North Carolina, Center for Urban and Regional Studies, 1972. 242 pp.

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255 45. Batley, R. hi. Nationwide Personal Transportation Study. Availability of Public Transportation and Shopping Characteristics of SMSA Households. Report No. 5. Washington, D.C.: U.S. Department of Transportation, Federal Highway Administration, Office of Highway Planning, 1972. 36 pp. Hittman Associates, Inc. Residential Energy Consumption in Single-Family Mousing. March 1973. U.S. Department of }lousing and Urban Development Publication No . lIUD~PDR-2 9-2 . Washington, D. C .: U.S. Government Printing Office, 1974. 174 pp. Jensen, M. The mc~del-law for phenomena In natural wind. Ingeni~ren 2: 121-128, 1958. Jordan, R. C., G. A Erickson, and R. R. Leonard. Infiltration measurements in two research houses. ASHRAE Trans. 69: 344-350, 1963 . Keyes, D. L. Population redistribution: Implications for environmental quality and natural resource consumption, p. 213. In B. J. L. Berry end L. P. Silverman, Eds. Population Redistribution and Public Policy. Washington, D.C.: National Academy of Sciences, 1980. Kittredge, J. Forest Influences. The Effects of Woody Vegetation on Climate, Water, and Soil, with Applications to the Conservation of Water and the Control of Floods and Erosion. 1st ed. New York: McGraw-Hill Book Company, Inc., 1948. 394 pp. Kronvall, J. Testing of houses for air leakage using a pressure method. ASHRAE Trans. 84 (Pt. 1) :72-79, 1978. Laschober, R. R., and J. H. Mealy. Statistical analyses of air leakage in split-level residences. ASHRAE Trans. 70: 364-374, 1964. Malik, N. Field studies of dependence of al r inf titration on outside temperature and wind. Energy Build. 1: 281-292, 1978. Manasseh, L., and R. Cunliffe. Office Buildings. New York: Reinhold Publishing Corporation, 1962. 208 pp. Mar in, A. Inf luence of stack ef feet on the heat loss in tall building=. ASHVE Trans. 40: 377-386, 1934. Mattingly, G. E., and E. F. Peters. Wind and trees : Air inf titration effects on energy in housing. J. Ind. Aerodyn. 2 :1-19 . 1977. McIntyre, D. A. Indoor Climate. London: Applied Science Publishers Ltd., 1980. 443 pp. Michelson, W. Time-budgets in envirorunental research: Some introductory considerations, pp. 262-268. In W. F. E. Preiser, Ed. Environmental Design Research. Sol. 2. Symposia and Workshops. Fourth International EDRA Conference. Stroudsburg, Pa.: Dowden, Hutchinson, and Ross, Inc ., 1973. Moschandreas, D. J., Ed. Indoor Air Pollution in the Residential Environment. Vol. IT. Field Monitoring Protocol, Indoor Episodic Pollutant Release Experiments and Numerical Analyses. U.S. Environmental Protection Agency Report No. EPA-600/7-78-229b. Research Triangle Park , N.C.: U.S. Environmental Protection Agency , Environmental Monitoring and Support Laboratory, 1978. 240 pp . Moschandreas, D. J. and S. S. Morse. The Relationship between Energy Conservation Measures; and Exposure to Indoor Toxic Pollutants. Paper No. 27b, pre';ented at the Anger ican Institute of

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2S6 Chemical Engineers 87th National Meeting, Boston, Massachusetts, August 19—LIZ, 1979. 49. Hoachandreas, D. J., J. W. C. Stark, J. E. IScFedden, and S. S. Morse. Indoor Air Pollution In the Residential Environment. vol. I. Data Collection, ArlalySi8 and Interpretation. U.S. Environmental Protection Agency Report ho. EPA-600/7-78-229a. Research Triangle Park: U.S. Environmenta1 Protection Agency, E:nvironaenta] Monitor ing and Support Laboratory, 1978. 201 pp. 50. Moschandreas, D. J., J. Zabranaky, and D. J. Pelton. Comparison ot Indoor~C)utdoor Concentrations of Atmospheric Pollutants. GE - ET Report Ho. ES-823. Palo Alto, Cal.: Electric Power Research Institute, 1980. 51. Ott, W. R. Buman Activity Patterns: A Re~rzaw or the Literature for Air Pollution Exposure Estimation. SIMS Technical Report. Stanford, Cal.: Stantord llni~rersity, Department of Statzat~ce. (to be published) 5;~. Ottensmann, J. R. Systems of Urban Activities and Times An Interpretive Review of the Literature. An Urban Studies Research Paper. Chapel Hill, N.C.: University of Nor to Carolina, Center for Urban and Regions1 Studies, 1972. 45 PP. 53. Panofaky, H. A. The at - Spheric boundary layer below 150 Meters. Ann. Rev. Fluid Mechanics 6:147-177, 1974. 54. Peterks, J. A., and J. E. Cer~ke Turbulence In building wakes, pp. 447-463. In K. J. "ton, Ed. Proceedings at the Fourtt, International Conterence on Wind Eftects on 8uz1dings and Structures, Heathrow, 1975. New York: Bridge University Press, 1977 . 55. Rand, G. B. Caution: The office environment may be hazardous to your health. AIA J. 68~121:38-41, 78, 1979. 56. Rz~ndill, A., B. Greent~al~t`, and E. Samson. Nationwide Personal Transportation Study. Mode of Transportation and Personal Characteristics of Trip~kere. Report No. 9. U.S. Department of Transportation, Federal Highway Administration, Office of Highway Planning. Washington, D.C.: U.S. Government Printing office, 1Y73. 49 pp. 57. Robinson, J. P. Changes In Americans' Use of Time: 1965-1S.75: A Prog reds Report . Cleveland, Ohio: Cleveland State Unz~eretty, Communications Research Center, 1977. 58. Robinson, J. P. Bow Americans Used Thee in 1965. Ann Arbor: University of Michigan, University H~crotilms International, 1977. 59. Robinson, J. P. Bow Americans Use Time: A Soczal-P~yc~ologica1 "aly818 at Everyday Behavior. New York: Preeger Publ18her8, Praeger Special Studies, 1977. 209 pp. 6 0 . Robinson , J . P ., P . E . Converee , anc! A. Szala: . Everyday ll$e In twelve countries, pp. 113-144. In A. Szalai, Ed. The Use of T - es Daily Activities of Urban and Suburban Populations In Twelve Countries. The }lag ue : Mouton ~ Co., 1972. 61. Stair, F. B., and K. L. Bettner. Theoretical model for relating indoor pollution concentrations Deco those outside. Environ. &1. Technol. 8: 444-451, 1974. 62. Sherman, M. B. Alr Int~ltration In Buildings. Berkeley, Calls University of California, Ph. D. Dissertation, 1981. (to be published as Lawrence Berkeley Laboratory Report LB - 10712)

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257 63. Spengler, J. O., B. G. Ferris, Jr., and D. W. Mockery. Sulfur dioxide and nitrogen dioxide levels inside and outside horned and the implications on health effects research. Environ. Sci. Technol. 13 :1276-1280, 1979. 64. Stopher, P. R., and A. B. Meyburg. Urban Transportation Modeling and Planning . Lexington, Mass.: D.C. Heath and Co., Lexington Books, 1975. 345 pp. 6 5. Stance, H . E. Nationwide Personal Transportation Study. Annual Hiles of Automobile Travel. Report No. 2. Washington, D.C.: U.S. Department of Transportation, Federal Bighway Administration, Of f ice of Highway Planning, 1972. 32 pp. 6 6. Strate, He E. Nationwide Personal Transportation Study. Automobile Occupancy. Report No. 1. Washington, D.C.: U.S. Department of Transportation, Federal Highway Administration, Off ice of Highway Planning, 19.t2. 32 pp. 6 7. Strate, B. E. National Personal Transportation Study. Seasonal Var. iatic~ns of Automobi le Tr ips and Travel . Report No . 3 . U. S . Department of Transportation, Federal Highway Administration. Washington, D.C.: U.S. Government Printing Office, 1972. 28 pp. 6 8. Svercl, P. V., and R. H. As in. Nationwide Personal Transportation Study. Home-to-Work Trips and Travel. Report No. 8. U.S. Department of Transportation, Federal Highway Administration, Off ice of Highway Planning. Washington, D.C.: U.S. Government Printing Of f ice, 1973. 104 pp. 6 9. Szalai , A., Ed. The Use of Time. Daily Activities of Urban and Suburban Populations in Twelve Countries. The Hague : Mouton & Co., 1972. 868 pp. 70. Szalai, A. Trends in comparative time-budget research. Am. Behav. Scientist 9~9) :3-8, 1966. 71. Tamura, G . T. Measurement of air leakage characteristics of house enclosures. ASHRAE Trans. 81(Pt. 1) :202-211, 1975. 72. Tamura, G. T., and A. G. Wilson. Air leakage and pressure measurements on two occupied houses. ASERAE Trans. 70 :110-119, 1964 . 73. Thuillier, R. H. Air Quality Considerations in Residential Planning. Vol. 1. Guide for Rapid Assessment of Air Quality at Housing Sited. Final Report. Hay 1978. O.S. Department of Housing and Urban Development (Off ice of Policy Development and Research) Report No. HUD-POR-524-1 . Washington, D. C .: U. S . Government Printing Off ice, 1980. 74. Thuillier, R. H. Air Quality Considerations; in Residential Planning. Vol. 2. Manual for Air Quality Considerations in Residential Location, Design and Construction, Final Report. May 1978. U.S. Department of Housing and Urban Development (Office of Policy Development and Research) Report No. BUD~PDR-524-2. Washington, D.C.: U.S. Government Printing Office, 1980. 7 5. Thuillier, R. H. Air Quality Considerations in Residential Planning. Vol. 3. Scientific Support and Documentation. Final Report 1978. U.S. Department of Housing and Urban Development (Of f ice of Policy Development and Research) Report No. HUD-PDR-524-3. Washington, D.C.: U. S. Government Printing Off ice, 1980.

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