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TV SOURCES AND CHARACTERIZATION OF INDOOR POLLUTION This chapter addresses several chemical pollutants with respect to their sources, concentrations, and indoor-outdoor relationships. In addition, with the aim of characterizing the general quality of the indoor environment, it considers temperature, humidity, unwanted sound, and electromagnetic radiation, such as the radiofrequency, infrared, ~risible, ultraviolet, and x-ray portions of the spectrum. In the case of some pollutants, information on health effects is scanty, at bent. To the extent possible, the health effects of such pollutants are discussed here. Detailed discussion of the health effects of other pollutants, on which more information is available, is to be found in Chapter VII. Radioactivity and formaldehyde emitted indoors from building product. are discussed in the first two sections of this chapter. Consumer products, a generic Source of indoor pollutants of many types, are discussed next. The chapter proceeds with sections on asbestos and fibrous glass {which occur in different forms in many indoor environments), combustion processes (especially of unrented cooking and heating appliances), and tobacco smoke {a hiahlv complex and ublaultous mixture of pollutants). Several indoor air pollutants can be _ . . _ _ , _ _ recognized by their odors. Such odors are often the first indications of deterioration in air quality and may themselves affect people's well-being adversely; hence, they are treated as a distinct category of pollutant in this chapter. Air temperature, radiant temperature, and air velocity and humidity affect the quality of the indoor environment through physiologic and sensory responses, so the thermal environment is also discussed in a separate section. Other physical factors of the indoor environment, such as noise and electromagnetic radiation, are d iscussed briefly in a f inal section. The diversity of subjects discussed in this chapter is evident. Some of the pollutants considered here may be associated with ~roluntery behavioral patterns, such as tobacc~o-amoicing, whereas others may be related to involuntary and unavoidable exposure, such as exposure to substances emitted from building materials. me reader should not infer any order of priority among the pollutants discussed here. An effort to attach priorities would require judgment" on exposures and effects, 57

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So and the order of discussion is not intended to indicate the application o f such j udgment . RADIOACTIVITY INTRODUCTION Radioactivity and ionizing radiation occur naturally throughout the biosphere, bath because of the presence of primordial radioactive elements and their decay products in the earth and because of natural processes (primarily cosmic radiation) that produce radionuclides or direct radiation fields. These natural sources expose humans to radiation both outdoors and in buildings. The magnitudes of various contributions to total radiation dose vary from place to place and between outdoors and indoors, and the type of radiation dose depends on the radiation source. At one extreme, the coemic-radiation field delivers a dose to the entire body; this dose is not affected greatly by the presence of a building and may be characterized prissily on the basis of altitude. At the other extreme, airborne alpha-emitting radionuclides may deliver doses specifically to the lungs, and their concentrations indoors may be strongly affected by the nature of building materials and other sources, such as soil and water, and by building operations, such as ventilation. As an intermediate case, the gamma-radiation field arising from radionuclides that are fixed in place typically exposes the whole body and is affected by radionuclide concentration, proximity, and shielding. . In the discussion that follows, we refer to radioactivity concentrations and radiation fields and, by inference, to radiation doses from sources that are.inside and outside the body. Radioactivity is given in curies' 1 Ct - 3.7 x 101 becquerele, so 1 psi ~ 0.037 Bq. Radiation fields can be specified in terms of energy flux' but it is more conventional in the present context to use units of dose rate, in which case the type of radiation has to be indicated. We use the red as the unit of (absorbed) dose when specify5ing q~-radiation fields (1 red - 0.01 J/kg, so 1 mead ~ 1 x 10~ J/kg). For gamma doses, the dose in reds is numerically equal to the dose equi~raler~- (D!:) in rema. A distinction must be drawn between the Tissue dose,. that actually received by tissue and therefore including self-shielding by the body, and the fair dose,. that deposited in air in the space under consideration. It is useful to atomize the dose-rate contribution in the United States from radiation arising outside buildings. Three recent summaries are those of the National Council on Radiation Protection and asurements34 and the U.N. Scientific Committee on the Effects of Atomic Radiation,.' which depended heavily on Oakley38 for U.S. data, and the 1980 BEIR report of the National Research Council. Is External radiation, that arising from sources outside the body, may be divided into two categories, cosmic and terrestrial. The average tissue dose rate outdoors from cosmic radiation is approximately 28 mrads/yr; the dose rate indoor e is slightly reduced by overhead

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as shielding (the NCRP report amounted a 10% reduction in average exposures). This contribution has a substantial altitude dependence, increasing from about 26 mrads/yr at sea level to about 50 mrads/yr at 1,600 a, the altitude of Denver. The average outdoor population- weighted tissue dose rate from terrestrial radionuclides--due principally to gamma rays from potassium-40, the thorium-232 series, and the uranium-238 series--is approximately 35 mrad~/yr. This dose rate varies substantially because of geographic variations in the distribution of these radionuclides. For estimating average terrestrial dose rates, the NCRP assumed that indoor done rates were 20% lower than outdoor rates. (It also assumed that the tissue dose was 20% less than the air dose.) Internal radionuclides contribute important beta and gamma doses (about 15 mrads/yr to cast of the body, primarily from potassium-40) and an important alpha dose (even if that to the lungs from radon and its progeny is excluded). The alpha dose arises primarily from internally deposited uranium-238 and -234, radium-226 and -228, and polonium-210 and varies greatly with body organ. One of the larger contributions, about 3 mrads/yr, is the polonium-210 alpha dose to the cells lining the bone surfaces. However, alpha particles have a greater biologic effectiveness than gamma rays, so the absorbed alpha dose contributes a DE some 10 times greater than that of the same (absorbed) dose of gamma radiation. Table IV-1 shows estimate. of various contributions to DE rates, in millirems per year, which are numerically equal to tissue dose rates (in millirads per year) for gamma and beta radiation. For alpha radiation, a quality factor of 10 was assumed (based on relative biologic effectiveness), although 20 is now recommended.' The value given for lung dose from inhaled radionuclides assumed a radon-222 concentration in air of 0.15 nCi/~3 (and slightly less than equilibrium amounts of its radioactive decay products, or progeny). The resulting DE has the largest value in the table. Nonetheless, this value appears more appropriate for outdoor than for indoor air, in which higher radon concentrations are found. All indoor dose rates from natural radiation sources are affected by buildings, and those from inhaled radionuclides are affected most strongly. The only natural airborne radionuclides of importance are radon and its progeny, principally the series beginning with radon-222, the alpha-decay product of radium-226 (a member of the uranium-238 series). Radon is a noble gas that can move from the site of its formation, giving it a substantial opportunity to reach air that is inhaled by humans. The short-lived decay products of radon--polonium, . . . . . ~ . . . . . _ ~ ~ _ lead, and b~mutn--are chemically active ana thus can De co~ec~ea An the lungs, either directly or through particle" to which they attach. The most important dose arises from alpha decay of the polonium isotopes. The decay sequence beginning with radium-226 is shown in Figure IV-1, and, from the biomedical point of view, effectively.ends with lead-210, because of its half-life of about 20 yr. Because the alpha energy associated with decays of the short-lived products to lead-210 poses the main risk, progeny concentrations are often expressed as the associated potential alpha-energy concentration. (PAEC) in air. The unit conventionally used for PAEC is the working

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60 TABLE IV-1 Summary of Average Dose }equivalent Rates from Various Sources of Natural Background Radiation in the limited Statesa Bone Radiation Source Gonads Lung Surfaces Marrow GI Tract Cosmleb 28 28 28 28 28 Cosmogenic radiormclides 0.7 0. 7 0.8 0.7 0.7 External terrestrials 26 26 26 26 26 Inhaled radionuclideed 1 OOe ~ Radionuclides in the bodyf 27 24 60 24 248 Tombs ~ rounded ~ 80 IS0 120 80 80 aReprinted with permission from NCRP.34 blfith 10: reduction for structural shielding. CWith 20X reduction for shielding by housing and 20X reduction for ahielting by the body. d Lung only; doses to other organs included in "Radionuclides in the body. eLocal DO rate to segmental bronchioles - 450 areme/yr. fExcluding cos~geni~ contribution. "Excluding contribution from ra~itomclides in gut contents.

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61 s~u lull ~SY 1~r 2 "eV - Pa '.~lUX,' 1.2 ~ 2 3 ~V '..U lUtIl ~ 25Y tO., .,'_ 4J - eV , ' '~h ~X,) 24 d 02.01 ~V "~h Ib} B0 a 106' 4e _ 47 - V . ~ ~ 1 1 ~1 r ~JC" 1500 ~ 48 - V sesnn 382d SS - V , ~Po (~) "-o ~' 3.0S~ 16 >< 10~s 60 ~V _7 ~ ~Y . t.~s, lC) ~ '. ,. 19? 04 3.3 - Y , "~~ IRaS)' "` tl" 268 mm ~t ~ 07. ~O - V CO1 ~V "~' I~E,' 50d ~1 2 - eV 86 - o l~bF) 138 d ~S 3 - eV '~ teaG) | s~ 1 . FIGllRE: IV-} Principal decay scheme of uranium-238 to radon-222 to lead-206, showing alpha ar~d beta decay; decay energies in millions of electron volts. Reprinted with permi,'lon {r~om National Council on Radiation Protection and Measurements. P-

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62 level (WL), defined as 1.3 x 105 MeV/L, the PANIC if radon-222 at 100 nCi/~3 is present with equilibrium amounts of its progeny. Done (and DE) rates may be inferred from the PAEC on the basis of relatively complicated modeling, provided that the progeny particle size distribution and other factors are prescribed. The character of a building may affect occupant radiation exposure in three principal ways: the building serves as a container for indoor~generated radon and its associated progeny, whether from building materials, underlying soil, or water and Gas; the building materials contain natural gamm=-emitters (potassium-40, the thori~232 series, and the uranium-238 series); and the building shields occupants from cosmic or external terrestrial radiation. The last two effect" tend to cancel one another. The building structure may, in unusual circumstances, also protect occupants from outdoor radon-urooenY . _ ~ _ ~ _ _, _ _ _, concentrations. However, the indoor concentration 18 ordinarily larger than the outdoor, and outdoor-generated radon usually contributes a "mall additive term to indoor concentrations. If this term is ignored, the steady-state indoor radon concentration for a f iced indoor radon source strength is inversely proportional to the air-exchange rate, the rate at which the indoor air is exchanged for outdoor air. The air-exchange rate for most U.S. buildings is around 1/h, with O.S/h to 1 . 5/h typical for residences (windows closed) . The air-exchange rate and other removal mechanisms also affect the ratios of radon-progeny concentration to radon concentration. Lack of removal implies activity ratios of 1, but substantially lower values have been observed. An equilibrium factor (F} is often defined as the ratio of the actual Pm3C to the PAE;C that would be associated with a specific radon concentration if the progeny were in equilibrium with this concentration. This section characterizes indoor airborne radionuclides and radiation, su~arizes measurements of actual concentrations or radiation f ields, briefly Indicates con~crol measures, and suggests subjects for further research. The major emphasis is on radon and its progeny. The radionuclides in this decay chain, even at typical outdoor concentrations, cause larger radiation doses to internal organs than all other airborne radionuclides. Furthermore, the radon and progeny concentration"may be substantially higher indoor-, particularly in building with low air-exchange rates. In addition. building oc`:upants receive external whole-body-radiation from radionuclides fixed in building materials and soil, and these doses are also given subetantial treatment. This radiation arises principally from several primordial radionuclides--potassium-40 and Sobers of the thorium-232 and uranium-238 decay series--with concentrations of around 0.1 pCi/g or greater in rocks, soil, and derivative building materials. There are also the decay chains in which radon-220, radon-222, and their progeny occur. \

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63 SC}URCES OF RADICXlilCLIDES AT RADIATION Building Mater ials Radionuclide Content. Few measurements and no wide~scale surveys of the radionuclide content of U.S. building materials have been made. Surveys of materials in Europe are summarized in UltSCEAR 1977, AMP. 50) which gives activity concentrations of potassium-40, radium-226, and thorium-232. As examples, average values for the concrete Ample groups examined range from 0.9 to 2.0 pCi/g for radium-226, 0.8 to 2.3 pCi/g for thoriu~n-232, and 9 to 19 pCi/g for potassium-40. By comparison, the ranges for brick are about 50% higher; those for cement are similar, except for potas~ium-40 (which is SO. less); and those for natural plaster are lower by about a factor of 5. Available U.S. data {Table IV-2) show concentrations in the same range, assuming that the series radionuclides are sufficiently close to equilibrium to permit comparison. In a number of cares, U.S. workers have examined the radionuclide contents of concrete in the course of selec~cing materials for low-background facilities for use in radiation- counting; 2' the values obtained are consistent with the European da=, although somewhat lower. The observed concentrations are also within the range of values typical for major rock types and "oils. Concentrations for building materials not derived from crustal components, such as wood, are much lower . Measurement programs have recently been initiated to characterize the radionucl~de contents of building mater ials as a basis for understanding the resulting effect on the indoor radiation environment. Kahn et al.25 have reported measurements of concentrations in various building material" in the Atlanta area; potassi~-40, radium-226 progeny, and thorium-232 progeny concentrations for samples of concrete, brick, and tile are given in Table TV-2. Lawrence Berkeley Laboratory has begun to survey concretes and other materials as part of a program on indoor air quality; radionuclide contents for concrete and rock-bed samples from a number of areas are given in the table. I' Considerably greater radionuclide concentrations may be found in building materials that contain residues from industrial processed. The principal example of such materials in the United States in concrete blocks incorporating phosphate slag Sequentially calcium silicate), a byproduct of phosphate production. As discussed by Roessler et al.,.2 this slag contains most of the radium-226 and uranium~238 found in the phosphate ore. For the electric furnace Process used in Florida, concentrations in the ore are about 60 pCi/g, and the slag has similar concentrations. A plane In A'zioame Musing Florida and Tennessee phosphate ores) sold slag to companies in Alabama, Mississippi, Tennessee, Georgia, and Kentucky. The concrete produced by these companies has radium-226 concentrations estimated. and in some cares measured, to be about 20 pCi/g.25 Phosphogypaum (essentially calcium sulfate produced by treatment of phosphate ores with sulfuric acid) may also be used for building materials, particularly wallboard. In this treatment, radium-226 follows the

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65 calcium, leading to tens of picocuries per grue in the gypsum but such gypsum has not been used on ~ large scale in U.S. wallboard. In contrast, concrete that incorporates phosphate slag may have been used in approximately 100,000 homes.2S Finally, awe fly ash from coal-fired power plants has been used in cement production, and tote use may continue. Heretofore, it has not been thought to contribute substantially to the radionuclide content of the resulting building material. IS Bnanation measurements on fly-ash concretes are now being performed at Lawrence Berkeley Laboratory. Radon Emanation. The effective radon-222 ser~eration rate in building ma~ceriale depends on the radi~-226 content, which varies widely, and on tbe percentage of radon formed that does not rain lodged in the matrix of the material. Radon that is not fixed in place may mc've through the matrix by diffusion or, if the material contain e large air spaces, by convection. Diffusive movement depends on the diffusion length of the ~nateris1 in question and on its thickness. The extent to which these processes occur depends not only on the material ' s characteristics, but also on environmental conditione-- pressure, temperature, and moisture content. A rule of thumb Wartimes cited {e.g., UNSCEAR.~) is that 1% of the radon-222 generated from materials in walls and ceilings escapee into the adjacent air space. However, recent measurements at Lawrence Berkeley "bora~cory and elsewhere have indicated that a considerably higher fraction can escape, e.g., from concrete. Ingersoll et al. cited eacape-to- production ratios of 0.08-0.25 for radon-222 from concrete. (Radionuclide contents for the sample groups examined are indicated in Table IV-2. ) Of most direct interest for indoor sir quality is the actual emanation rate, often given as picocuries per square meter per second and sometimes as picocuries per gram per second. Measurements for various materials give emanation rates over a wide range. For exe ~ le. Euro Ian gypsum board and bricks yield radon-222 at about 0.3 x 10- pCi/m -a, whereas rates for European concretes range from 0.001 to 0.2 pCi/m2-~.2. 32 Preliminary measurements of radon-222 emanation rate per unit mast for sample groups of concrete from U.S. metropolitan areas (Table IV-2) give averages that range from 0.4 to 1.2 pCi/kg-h (0.8 pCi/lcg-h yields approximately 0.03 pCi/~-s for O.l-~thick concrete). Several rock samples from solar-beat storage beds averaged 0.5 pCi/kg-h, although radium-226 contents were considerably higher t ban those for the concrete samples. I' The resulting indoor radon-222 concentrations depend on the amount of such material in the structure, the interior volume, and the air~exabange rate. For an air-exchange rate of lih and a ratio of indoor emanating surface to indoor volume of 0.5 m~/m3, an emanation rate of 0.03 pCi/m2-e corresponds to a radon-222 concentration of about 0.04 nCi/m3. If the equilibrium factor is 0.5, this would yield a PANIC of about 0.0002 WL. Direct measurement of emanation rates of materials made with industrial byproducts (such ens phosphate-alag concrete is underway. but results are not available. Because these materials may contain 20 times a. much radion-226 as a typical concrete, radon-222 contributions

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66 of up to several nanocuries per cubic - ter of radon-222 and a corresponding increase in the PANIC could be expected if the same emanation ratio pertains. Measurements of emanation rate vary by more than an order of magnitude, I' no it is difficult to use radium content to predict the contribution of a particular material to indoor radon content. For this reason, more comprehensive information on diffusible fraction, diffusion length, etc., and their dependence on material or environmental factors is required before we can characterize building materials on the basis of radionuclide content. If this information becomes available, radionuclide Contents may then be helpful in characterizing indoor concentrations on a broad scale, e.g., by geographic area. Ilowever, the dependence of diffusion and emanation r ates on environmental factors, such as pressure and temperature, and on the Moisture content of the material may limit the possibility for such characterization. In some cases, radon-220 (.thoron.) and its progeny, ordinarily present at much lower concentrations than radon-222 and its progeny, may assume importance, particularly when mechanisms exist for transporting emanating radon-220 rapidly into the air space of interest. In comparison with the half-life of radon-222, the much shorter half-life of thoron, 55 s, caches the measured radioactivity in curies to be a characteristic of secondary interest. However, the PAEC still gives a relatively direct indication of possible dose to the lung. One WL of radon-222 progeny has the same PAEC as that associated with progeny in eguilibrium with thoron at 7 nCi/~3. To the extent that uranium-238 and thorium-232, which have similar half-lives, have similar activities In source materials, the PAEC from their progeny, radon-220 and -222, can reach similar values if rapid transport mechanisms exist. This may occur, for example, in solar buildings that sweep air through rock or concrete thermal-atorage beds. A few efforts have begun to measure thoron emanation rates, but results are not yet available. Gamma Radiation. The energies and intensities of photons f rom decay of natural radionuclide. have been well characterized. The external dose from radionuclides in building materials is due to the gamma rays emitted and depends on the geometry of the structure and attenuation by the materials, as well as the gaama-ray energies. A simple expression may be derived for the -ray air dose in a hole in an infinite uniform medium:25 X',,, ~ (2.43 Vrad/h) (1i;UCU + EThcq~h + EKCK} . where Cu. CTh, and CR are the concentrations (in picocuries per g ram) of uraniu~238 and it's progeny, thor lum-232 and its progeny, and potassium-40, respectively, and Eu, ETh, and E': are the average ga~a-ray energies per disintegration of the same radionuclides (including disintegration of the progeny for the uranium and thorium -eeriest. Used Eu ~ 1.72 Mev, E',h ~ 2.36 MeV, and ER a 0.156 MeV, 25 t" ~ 4 ECU + 5.7CTh + 0.38CR, in microrads per

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67 hour. The stated dose contributions from the uranium and thorium series are slightly less than those cited elsewhere. e.g., by Krisiuk et al., 27 who may have used older information on decay schemes. For the radionuclide contents cited in Table IV-2, the three terms in the expression for to contribute comparable amount". (An analogous expression for the dose from a flat plane is cited in the section on soil. ~ For an actual structure, the geometry is complex and Salaried; in addition, the building materials may attenuate the external radiation dose from other sources. Moreover, radon-222 and its progeny may be present in the material at less ton equilibrium values, thereby decreasing the corresponding gamoa-ray dose. The radon-222 escape-to~production ratio is most often in the range of low to 0.25, causing a small reduction in the value of X. The effects of geometry and attenuation cannot be so simply characterized. Dose-rate expressions from various workers, pertaining to a variety of structures, have been summarized.3' Some of these expressions account for reduction of the dose rate from outdoor sources. Moeller _ al.' described a computer program suitable for analysis of varied geometries. The infinite-geometry case yields air dose rates of about 8 wads/in for a potassiumr40 concentration of 8 pCi/g and uranium-238 and thorium-232 series concentrations of 0.5 pCi/g. An infinitely thick slab of such material would contribute about half thin dose rate at its surface. As discussed earlier, ~ typical outdoor tissue dose rate from terrestrial radionuclides is 35 mrads/yr or 4 prads/h. {Owing to shielding by the body, the tissue dose rate is about 20% less than the air dose rate.} Soil and Groundwater Radionuclide Content. Radionuclide concentrations of major rock types and soil have been summarized.'. U.S. soil values of 0.6, 1.0, and 12 pCi/g have been stated for uraniu~-238, thorium-232. and potasstum-40, respectively, on the basis of 200 measurements of g~mm^-ray dose rate cited by Lowder et al.' These values vary by a factor of around 3 from place to place. Values for crustal rocks'. typically lie within this Dame range, but are considerably higher for some formations. For example, the phosphate rocks of Florida contain the uranium-238 Series at tens of picocuries per gram, but normal amounts of thoriu~-232s commercial uranium ore bodies in the United States have uranium-238 concentrations of hundreds of picocur ies per gram and higher. Radon Emanation and Transport. The uranium-238 series, typically presenS in soils and rocks at concentrations of about 1 pCi/g, includes radium-226, the source of radon-222. The actual radon-222 emanation rate from the ground depends, as for building materiels, on the percentage of diffusible radon, diffusion length, and other transport mechanisms (including groundwater) in the soil. A review of available

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214 infrared, visible light, ultraviolet, and x-ray portions of the electromagnetic spectrum. The freguencies of the electromagnetic radiation discussed here range from 104 Ez {radiofrequency) to 1015 Hz {ultraviolet). Table IV-24 s''mn~rizes the frequency distribution for each of these portions of the spectrum and of audible sound, which is transmitted via the vibration of air molecules. SOUND AND NOISE Phvaical Character i8tiC8 The audibility of sound depends on intensity and frequency, with a maximal human response in the region near 3 x 103 Ez. A sound with predominant frequencies below 100 Hz or above 104 Hz may require ~ million times more energy to have the same audibility as a sound with a predominant frequency of 3 x 103 Ez. A method of weighting the pressure exerted by the sound waves at different frequencies has been developed to compensate for these variations. The decibel values (which constitute a logarithmic intensity scale) cited herein are measurements with level A weighting, the scale that most closely matches the response of the human ear. The difference. in the treatment of the intensity content of a sound are alight and do not change substantially from one source to another."' Sounds in the indoor environment are generated both outside and inside the occupied space. Table IV-25 gives examples of sound intensities in the outdoor environment. Table Iv-26 lists sound intent ities produced by typical household appliances in the indoor environment. Sound intensities are usually measured by a meter satisfying the requirements of American National Standards Institute Specification SI.4-1971 {for sound meters). PsYchoPhysiolosic Effects The possible effects of sound include permanent and temporary 108S of hearing, cardiovascular disease, sleep disruption, and paychologic effects. :. The physiologic and psyabologic responses to sound may be transitory; ~. however, there i'; insufficient information on the effects of sound by itself or in combination with other stressore. Sound at intensities that are found to be objectionable will affect productivity and decrease enjoyment of the environment. ~. '~e EPA has identified sound intensities that, if not exceeded, should protect against some of the adverse effects of sound. ~. These values are expressed in term of maximal 8-h OCR for page 57
215 TABLE IV-24 Radiation Wavelengthe and Frequencies Type of Radia~cion Wave length Frequency, Hz Ultraviolet Ultraviolet C 0.19~0.28 vm 1.07 x 1014-1.58 x 10~5 Ultraviolet B 0.28-0.315 um 9.5 s 1014-1.07 s 124 Ultraviolet A 0.315-0.4 ym 7.5 s 101 -9.5 s 10 Visible light 0.4-0.7 llm 4 29 s 1ol4_7 5 x 1ol4 Infrared 4 14 Near infrared 0.7-1.4 um 2.14 x 101 -4.29 ~c 10 Infrared 1.4-3 pm 1.00 ~c 1011-2.14 ~c 10 4 Far infrared 3-1,000 um 3 x 101 -1.00 ~c 10} Radio frequency ~ 1 1 Microwave 1-1,000 ~ 3 x 1O7-3 x 10 Ves~y high frequency 1-10 m 3 x 10 -3 x 10 High frequency 10-100 m 3 ~c 10 -3 ~ 10 Medium frequency 100~1, 000 m 3 x 1O4-3 x lO5 Low frequency 1,000~10,000 m 3 x 10 -3 x 10 Very low frequency 10,000-30,000 m 1 x 10 -3 x 10 Sount, audible 0.016-20.0 o~ 15-2 x 104

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216 TABLE IV-2 5 Examples of Outdoor Day-Night Average Sound Intensities at Various Locations a Location Apartment next to freeway Downtown with some construction Urban high-dens ity apartment Urban row housing on major avenue Old urban residential area Wooded res idential area Agricultural cropland Rural residenelal area Wil de rnes s ambient aData from Council on Enviror~ental Quali~cy. 4 TABLE IV-2 6 Average Sound Intensity, dB(A) 88 79 78 68 59 51 44 39 35 Examples 0 f Sound Intensities Generated Indoors by Household Appliancesa Appl lance Blende r Garbage disposer Window air conditioner Re f rigerator Vacuum cleaner Hair dryer Mixe r aData fray Jones e 8 Average Sound Intensity, dB (A) 80-90 80 60 45 70-75 78 82

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217 considered safe. However, above 110 do, sound is so intense that most people experience pain or a tickle in their ears. ~. Although it is difficult to determine the exact day and night indoor sound intensities, studies have indicated that an intensity of 6 0 . 4 dB with a s tandard deviation of 5 . 9 dB can be expected in a typical urban residential area, with instantaneous intensities exceeding 80 dB. 12 An exacted intensity of 60.4 do is below the 70 dB recommended by the EPA to prevent hearing loss, but it is well above the intensity recommended to aneroid interference and annoyance. Therefore, day and night sound intensities in the 100-site EPA survey may contribute to speech interference, reduced worker productivity, and annoyance.iotpp. 66-69) A high intensity of background noise in urban areas stemming primarily from transportation appears to affect the developing fetus. Women exposed to aircraft noise have a higher proportion of low-birthweight children, who are at higher risk of mortality and both physical and mental effects.~(PP 110-111) This association cannot be separated from the social status of the women (a codetermining variable), inasmuch as many members of the lower social classes live in Noisy areas. Exposure to high intensities of sound affects communication and learning, including the acquisition of language.~(P 115) Adaptation or resignation to annoyance may occur, and there do not appear to be groups of people that are particularly sensitive. After-effects of noise have been noted at home and at work, and noise appears to influence aggressiveness and minimize voluntary helping behavior.~otPp. 120-12 RADIOFREQUENCY AND MICROWAVE RADIATION (104 to 3 x 1011 HZ . Phys ical Character istics Although the physical characteristics of all electromagnetic radiation are similar, the frequency is inversely proportional to wavelength, and the effects of the longer wavelengths, such as radiofrequency radiation, are radically different from those of the shorter-wavelength ioniz ing radiation, such as x rays and gamma rays . The photon energy in radio waves is so small that there is no ionization when it is absorbed in an organism. Is Table IV-27 summarizes the radiation properties of some common nonionizing-radiation systems and their expected far-field power densities. Energy radiated by these systems can be additive, provided that the frequencies are within the same octave band. For the purposes of this report, the densities of all radio- frequency energies generated outdoors are defined as Background power densities, ~ and those of radiofrequencies generated indoors as Generated power densities.. Some radiofrequency energy is generated in the indoor environment. In general, all electric equipment produces come radiofrequency radiation. However, all but a few electric devices radiate energy at

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219 well below the American National Standards Institute recommended exposure limits, even in combination with one another. One ma jor exception is the microwave oven. Under normal operating conditions, a residential microwave oven radiates approximately 1 mW/cm2 at the Real on the door. However, If the door is defective, values in excess of 1 W/cm2 can be achieved. PsYchophYs ioloq ic Ef f eats Effects of radiofrequency radiation can be divided into two major categories: t~ thermal effects (when the radio-wave energy is converted into heat) and nonthermal effects (which cannot be directly explained by thermal equivalents). Biologic effects depend on the f requency and the intensity of the radiation; the duration of exposure; the dielectric constant, temperature, and thermal conductivity of the irradiated tissue; the ability of the tissue to dissipate heat; and the dimensions of the body. Absorption of microwave radiation by body tissues results in an increase in temperature, often producing internal burns due to local hot spots caused by nonuniformity in the f ield. The eyes and testes were found to be the most sensitive. I' Specific effects at the cellular or molecular level were postulated more than a decade ago without resolution of the importance of these effects with respect to biologic damage. 3 The possibilities of nonthermal effects, such as rearrangements within macromolecules and subcellular structures, have been under investigation for many years, but further studies will be necessary to clarify the issues. It Is relatively clear that metabolic and functional disturbances at the cellular level can be caused by microwave radiation, but the mechanisms of these ef fects are not yet well understood. Table IV-28 characterizes the relative rates of absorption by the human body; however, it is difficult to determine the exact effect of each frequency. Because the radiofrequency energy generated indoors is low, the ma jor emphasis should be on outdoor sources. Indoor radiofrequency f ields are generally lower than outdoor. Osepchuck has discussed sources of microwave and other forms of radiofrequency energy . FAR-~NF~D AND INF=~D =DIATION {3 x 1011 HZ to 4 .3 x 1014 HZ Physical Character istics . The infrared energy spectrum ranges from far-infrared (3 x 10 Hz to 1014 Hz), through infrared (1.0-2.14 x loll Hz), to near- infrared (2.14-4.29 x 1014 Hz). Infrared radiation is produced naturally by the sun and by all common heating and artificial-light sources. The incandescent lamp is one of the major sources of infrared radiation and the most common artificzal-light source in the indoor environment. Of the total input wattage of an incandescent lamp,

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220 TABLE IV-28 Relative Absorption of Radiofrequencies by Hen Bodya Frequency, 106 Hz <400 400-1, 000 1,000~3,000 3, 000~10, 000 Haximn1 Absorption by Human Body, <50 50~100 20-100 >50 aData from U. S. Department of Health, Education, and Welf are . 13

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221 75-808 is converted to near-infrared and infrared radiation.' The ACGIE has adopted ~ TLV of 10 mW/ce2 for infrared radiation in the workplace. The power density 2 ~ from ~ 100-W lamp is approximately 0.6 mW/cm2 for the total infrared spectrum. Sunlight on the earth's surface produces a flux of about 70 mW/cm2, of which about half is infrared. Psychophvaiologic Effects Depending on its wavelength, infrared is absorbed in the surface of the skin (wavelengths larger than 2 ye) or can penetrate asveral millimeters (waveleng the between O.7 and 1.5 And. Safety standards in industrial environments are based on the risk that infrared radiation may induce cataracts in the eyes of persons exposed to excessive infrared radiation, such as glassblowers or open-hearth steelworkers.~. Excessive infrared radiation is most easily controlled by shielding the source with reflecting metallic foils. VISIBLE RADIATION Physical Character tStiC8 Radiation in the near-infrared and visible spectrum is produced by many sources, both natural and artificial. Our sense of sight, feeling of well-being, and comfort are all. to a great extent, influenced by Risible and near-infrared radiation. Psychophysiologic Effects Retinal burns from observation of the sun have been described throughout history. Chorioretin-1 burns rarely occur from exposure to artificial light, because the normal aversion to high-brightnese light sources (the blink reflex) provide. adequate protection , unless the exposure is hazardous within the duration of the blink reflex. Many factors at feet the usefulness of visible light . Among the most important are discomfort glare and disability glare. Light sources can cause ~ reduction in contrast of an image, owing to scattered visible radiation, by adding a uniform veil of luminance to the object. This effect, commonly called .veiling luminance,. may cause a reduction in visual performance without physical damage. Discomfort glare is a sensation of annoyance or pain caused by brightness in the field of view that is greater than that to which the eyes are adapted. It has been shown that the threshold of discomfort glare changes as ~ function of age.2 Although discomfort glare does not necessarily interfere with visual performance, it can cause eye strain and contribute to fatigue. Disability glare and ocular stray light influence one's ability to perform a task by artificially veiling

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222 the contrast of the visual target. It is therefore a great contributor to eye fatigue. ULTRAVIOLET RADIATION (0 . 75-1. S8 x 1015 Ez; - wavelength, 0. 19-0.400 =) Physical Characterstics Ultraviolet radiation is divided into three wavelength categories: ultraviolet-A (W-A), 0 . 315-0 .400 - ; ultraviolet-B (W-B), 0.28-0.315 - ; and ultraviolets (W~C}, 0.19-0.28 - . All fluorescent lamps emit W-A, but not W-B or ARC. High-inten~ity d ischarge lamps produce W-A, W-B, and some ARC. Incandescent lamps produce small amounts of W-A, and essentially no W-B and ARC. Ultraviolet radiation is measured with specialized radiometric photome ters . Psychophysiologic Ef feats UV-B and W~C are known photocarcinogens. s Doses of W-B and W~C 10 times the human minimal erythema dose (MET)) have initiated squamous cell carcinomas, and chronic continuous exposure to W-A can also have a carcinogenic effect. s The ACGIH recommends limits on workplace ultraviolet exposure that depend on wavelength and on the duration of exposure.' For W-A, the intensity should not exceed 1 mW/cm for more than 1,000 a, nor s hould the dose exceed 1 J/cm2 i f g iven in less than 1, 000 s . For W-B and Wee, the dose should not exceed about 3-10 =/cra2 in any 8-h period. The degree of hazard seems to be associated with the erythemal efficiency of each frequency. ~ s SUMMARY Ionizing and nonionizing electromagnetic radiation occurs in the indoor environment. This radiation can be harmful, and one cannot always sense its presence. Sound can generally be heard and in some cases felt. Excessive sound can cause deterioration of hearing acuity and, if extremely intense or prolonged, cause deafness. Background sound in the urban residential environment can exceed the recommended intensities and result in interference and annoyance. Sound of 70-80 do, commonly found in indoor environments, can inhibit task performance and possibly contribute to aggressive human behavior. ~ Infrared, far-infrared, and radiofrequency radiation produce no visible or audible evidence of their presence. However, infrared radiation does provide sensory indication of its presence by heating of human tissue. Far-infrared and radiofrequency radiation, however, provide no indication of their presence, unless their power levels are

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223 so high as to increase skin temperature. Heating of human tissue occurs because of the infrared output of incandescent lamps. However, the detrimental effects of this heating have not been fully investigated. Surveys have shown that in several cities 98% of the people are exposed to less than 1 ~W/cm2 from broadcasting transmitters.' However, ultrahigh-frequency television transmitters can radiate radiofrequency pollution to adjacent buildings at 5-200 W/cm2 . Ultraviolet-A, visible light, and near-infrared radiation can produce surface heating of human and animal tissue. These frequencies are of concern because of their ability to affect human performance. The veiling reflections caused by most artificial lighting systems can have substantial influence on human visual performance. Reduction of veiling reflections can increase visual performance and decrease the energy consumed by lighting systems. Transient adaptation (dilation during or immediately after eye movements) i. caused by sudden changes in the visual spectrum power. Transient adaptation contributes to eye fatigue and decreased visual performance. REFERENCES 7. 1. American Conference of Governmental Industrial Hygienists. ILUs. Threshold Limit Valuen for Chemical Substances in Workroom Air Adopted by ACGIH for 1980 . Cincinnati: Amer ican Conference of Governmental Industrial Hygienists, 1980. 93 pp. 2. Bennet, H. J. Discomfort Glare: Demographic variables, p. 6. IER] Special Report No. 118, 1976. 3. Cleary, E. Biological Effects and Health Implications of Microwave Radiation. Symposium Proceedings. Richmond, Virginia, September 17-19, 1969. U. S. Department of Health, Education, and Welfare, Bureau of Radiological Health Publication No. BRH/DBE 70-2. Washington, D.C.: U.S. Government Printing Office, 1971. 265 pp. 4. Council on Environmental Quality. Noise, pp. 533-576 . In Environmental Quality--1979. The Tenth Annual Report of the Council on Environmental Quality. Washington, D.C.: U.S. Government Printing Office, 1980. 5. Cunningham-Dunlop, S., and B. H. Kleinstein. Wavelength dependence, pp. 51-61. In Carcinogenic Properties of Ionizing and Nonionizing Radiation. Vol. I. Optical Radiation. DREW (NIOSH) Publication No. 78-122. Washington, D.C.: U.S. Government Printing Office, 1977. Geen, R. G., and E. C. O'Neal. Activation of the cue-elicited aggression by general arousal. J. Pers. Soc. Psychol. 11:289-292, 1969. Janes, D. E., Jr. Radiation surveys--Measurement of leakage emissions and potential exposure fields. Bull. N.Y. Acad. Med. 55:1021-1041, 1979. 8. Jones, H. W. Noise in the Human Environment. Edmonton, Alberta: Environmental Council of Alberta, 1979. 9. Kaufman, J. E., and J. F. Christensen, Eds. IES Lighting Handbook. The Standard Lighting Guide. 5th ed. New York: Illuminating Engineering Society, 1972.

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224 1U. National Research Council, committee on Apprales1 ot Societe1 Consequences of Transportation Noise Abatement. Noise Abatement: Policy Alternatives for Transportation. Wanton, D.C.: National Academy of Sciences, 1977. 206 pp. osepobuck, J. M. Sources and bB8tC characteristics of microwave/RF radiation. Bull. N.Y. Acad. Ned. 55:976-998, 1979. Schultz, T. J. Noise Assessment Guidelines. (Technical Background for Norse Abatement In BUD's Operating Programs.) U.S. Department of Housing and Urban Development Report No. TE/NA 172. Washington, D.C.: U.S. Government Printing Office, 1971. 210 pp. 13. Salty, S. W., and D. G. Brown. Radio Frequency and Radio HIcrowave Radiation Levels Resulting from Mhn-Made Sources in the Washington, D.C. Area, pp. 1-13. U.S. Department of Bealtn, Education, and Welfare Pub. No. (FDA)72-8015. Washington, D.C.: U.S. Government Printing O$tice, 197Z. 14. U.S. Environmental Protection Agency, Ot$lce of Nolse Abatement and Control. Tnformatzon on Levels of Environmental Noise Red taite to Protect Public Health and Weltare With an Adequate Margin of Safety. O.S. Environmental Protection Agency Report No. 550/9-74-004. Washington, D.C.: U.S. Government Printing Office, 1974. tZ141 pp. 15. Vogelman, J. H. Physical characteristics of microwave and other rad~ofrequency radiation, pp. 7-10. In S. F. Cleary, Ed. Biological Effects and Health Implication. of Microwave Radiation. Symposium Proceedings. Richmond, virgins, September 17-19, 1969. U.S. Department of Health, Education, and Weltare, Bureau of Radiological Bealth Publication No. BRE/DBE 70-2. Washington, D.C.: U.S. Government Printing Office, 1971. 16. Wallace, J., P. M. Sweetnam, C. G. Warner, P. A. Graham, And A. L. cocbraner An ep~demtological study of lens opacities among steel workers. Br. J. Ind. Mea. 28:265-Z71, 1971. 17. World Health Organization. Health Bazards In the Human Environment. Geneva: World Health Organization, 1972. 387 pp.