Indoor Pollutants (1981) / Chapter Skim
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II. Summary and Conclusions
II. Summary and Conclusions
Pages 30-45
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From page 30... ...
Indoor concentrations are affected by various factors, including ventilation rate, deposition of radon progeny on indoor surfaces, and interactions of radon progeny with fine particles from various sources (e.g., tobacco smoke and house dust)
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From page 31... ...
Owing to the time spent inside residences (including mobile bones}, offices, and other indoor environments, human exposures to indoor formaldehyde are markedly higher than exposures to outdoor formaldehyde. Typical indoor formaldehyde concentrations in buildings with products containing urea-formaldehyde resins range between O.OS and 0.3 ppm, although in some unusual instances concentrations of a few parts per million have been measured in bosses with OF foam insulation.
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From page 32... ...
In public buildinqs, the indoor concentrations are usually lower than observed residential concentrations, except under conditions of exceptionally heavy smoking, as in bars, or in office buildings with underground garages and improperly designed or malfunctioning ILIAC Myers.
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From page 33... ...
Indoor hourly concentrations of nitrogen dioxide '.rary between 50 and 500 ppbs indoor peaks of 700 ppb have been measured. Typical weekly indoor concentrations of nitrogen dioxide range from 20 to 100 ppb.
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From page 34... ...
concentrations is greater than 1 for about 90% of the total monitored hours; that is, the SAC concentrations observed in the residential environment are ale - at always higher than the outdoor concentrations. Fluctuations in the indoor concentrations may be associated with cooking, cleaning, and other activities.
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From page 35... ...
Indoor ozone has been measured at up to 120 ppb; typical concentrations are between O and 20 ppb. Sulf ur Dioxide Indoor sulfur dioxide concentrations are usually lower than corresponding outdoor concentrations.
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From page 36... ...
Almost all numerical models are mass-balance equations that simulate the dynamic relationships among indoor pollutant concentrations, outdoor concentrations, indoor sources, and sinks ~ including ventilation)
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From page 37... ...
Indoor air quality, and therefore exposure to pollutants, varies geographically as a function of outdoor regional air quality and as a function of the rural, urban, or suburban character of the location of the indoor environment in question. In rainy residences, the indoor sir quality does not vary substantially.
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From page 38... ...
307-322) The radon gas that diffuses out of radium-bearing building materisIs, subsurface soil beneath buildings, and well water into the indoor air undergoes radioactive decay.
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From page 39... ...
The health effects of much smaller amounts of radon progeny from indoor exposures can be estimated on the basis of a linear, no-threshold dose model, which yields upper-limit estimates of excess cancer in populations exposed to various indoor concentrations of radon and radon progeny. Lifetime cumulative exposures to radon progeny that result from current indoor exposures are lower by approximately a factor of 100-10,000 than those received by the U.S.
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From page 40... ...
A preliminary report from the Chemical Industry Institute of Toxicology teas about that formaldehyde induces nasal cancer in laboratory rats and in some of the laboratory mice similarly e^pveed at the high dose. Nass1 cancer tree developed in the group of rats exposed at 15 ppm and 6 ppm, and dose-related histologic changes of the nasal mucosa in rats exposed at 2 and 6 ppm.
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From page 41... ...
Although chronic animal inhalation studies and community air-pollution epidemiology studier using central ~sonitorinq-station data have not established that exposures at or near the NhAQS for nitrogen dioxide produce measurable health effects, several recent studies of the health statue of children living in homes with gas ranges have shown that they had more respiratory illness and poorer respiratory function than children living in comparable homes with electric ranges. Increases in carbon monoxide sufficient to cause measurable health effects are usually associated with improperly operated flames or especially prolonged use of unrented space-heatere.
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From page 42... ...
Other respiratory diseases, such as the con cold and pulmonary infections, involve airborne transmission. Because of the important role of respiratory diseases in overall acute morbidity, airborne transmission of contagious agents is important in the indoor environment.
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From page 43... ...
This kind of environmental control may be difficult to provide. However, the comfort-discomfort relationship may be one of the more important aspects to consider in evaluating the performance of indoor environmental control systems.
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From page 44... ...
Although environmental criteria and control variables can be identified and described, the capability of sensing the appropriate variables and controlling the system to meet the specified criteria is severely limited. Moreover, most indoor environmental control systems must attempt to respond activity or passively to all five of the Control variables simultaneously.
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From page 45... ...
. Thus, two general conclusions can be drawn: control methods may not be capable of adequately responding to environmental changes as energy-conser~ra~cion measures and cost contraints are applied; and the quality of the indoor environment need not be degraded, but can be enhanced if care is exercised in the selection and implementation of the energy and cost oonatrainta.
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