Activity building materials

Acceptable indoor air quality (lAQ) is defined as air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80%) of the people exposed do not express dissatisfaction (ASHRAE, 1989). Some of these indoor air contaminants are particulates, vapors, and gases that may be generated by occupants and their activities, building materials, furniture, equipment and appliances present in indoor space, operations and main-... 

From the baseline information, C02, VOCs and ventilation rate profiles have been identified. Although the levels do not generally exceed local threshold levels (ENV, 1996), it is important to understand how these profiles come to be, what their potential effects on sensory perception and health may be, what emission strengths they have and how they may be apportioned to various sources such as humans and human-related activities, building materials and the ventilation system. 

VOCs are emitted indoors by building materials (e.g., paints, pressed wood products, adhesives, etc.), equipment (photocopying machines, printers, etc.), cleaning products, stored fuels and automotive products, hobby supplies, and combustion activities (cooking, unvented space heating, tobacco smoking, indoor vehicle use). 

At many sites, the subsurface environment will be anoxic or even anaerobic due to the activity of aerobic and facultatively anaerobic bacteria in the surface layers of the soil. It is therefore essential to take into consideration the extent to which anaerobic degradation may be expected to be significant. Reactions may take place under sulfidogenic or methanogenic conditions, and the occurrence of sulfate at sites containing building material waste and the metabolic versatility of sulfate-reducing bacteria makes them particularly attractive. 

Much building material has been derived from two monomineral sedimentary rocks gypsum (composed of hydrated calcium sulfate) and limestone, which consists of calcite (composed mostly of calcium carbonate). Freshwater and seawater contain dissolved calcium carbonate and calcium sulfate. Most limestone and gypsum are formed when, as a consequence of the evaporation of water, calcium sulfate and calcium carbonate precipitate out of the water solutions as either gypsum or limestone. Limestone is also formed as a result of the activity of living organisms. Many sea- and freshwater animals, such as snails, clams, and corals, as well as some water plants, draw... 

Building material Ra-226 activity concentration (Bq kg-1) Range and mean Exhalation rate per unit mass and unit Ra-226 activity concentration (Bqh lkg l)/(Bqkg l) Estimated range of exhalation rate frcm typical walls (Bqh l m 2) ++... 

More, H. Radionuclides in building materials, a summary of activity concentrations in samples investigated at the National Institute of Radiation Protection, Report 85-08, National Institute of Radiation Protection, Stockholm (1985) (in Swedish). 

This very long half-life (1.25x1(r years) isotope comprises 0.0117 percent of all potassium. Thus, this isotope is present in all of us and has always been so. In addition, the materials around us, including the soil and the building materials, contain both potassium and the heavy naturally occurring radioactive elements thorium and uranium that contribute to a level of radiation to which we are all continuously exposed. Thus, there is always radiation exposure to the general public and we must understand the exposure due to radon in this context. The amount of radioactivity is described in units of activity. The activity is the number of decay events per unit time and is calculated as follows... 

This example (the cyanohydrin reaction) appears to me to provide a simple solution for the natural asymmetric synthesis. The formation of the sugar, as the plant physiologists assume, occurs in the chlorophyll grain, which itself is composed of optically active substances.. . . The prepared sugar is released and later on used by the plant, as is known, for the preparation of other organic components. Their asymmetry is thus explainedfrom the nature of the building material. Of course, they also provide material for new chlorophyll... 

Macroelements, as well as basic elements are essential for plant and animal organisms. They are the building materials that support tissue, teeth, skin, and hair, play an important role in water-electrolyte management and pH regulation, and are parts of many active compounds vital for metabolic processes. 

The PBDEs (decaBDE, octaBDE, and pentaBDE) and are used as flame retardants in plastics, electronic equipment, printed circuit boards, vehicles, furniture, textiles, carpets, and building materials. Global demand has increased rapidly since the 1970s with 70,000 tonnes produced in 2001. Their flame retardant activity relies on decomposition at high temperatures, leading to the release of bromine atoms. This slows the chemical reactions that drive 02-dependent fires. HBCDs are a flame retardant added to extruded and expanded polystyrene that is used as thermal insulation in buildings. 

Decontamination of JACADS will require chemical, mechanical, and thermal processing. The removal of critical structural components and systems from buildings will have to be planned to ensure structural stability. Residuals of any of the agents processed at JACADS (HD, GB, and VX) may be exposed during disassembly activities. These residuals will be harmful to anyone in the immediate area If they are vaporized, airborne agent concentrations could be harmful, so decontamination procedures for equipment, waste streams, and building materials must ensure that agent residues are destroyed, and the destruction must be verified. 

Limewater is a saturated aqueous calcium hydroxide, Ca(OH)2, solution. To make limewater, a small amount of calcium hydroxide is needed. Calcium hydroxide is marketed commercially as slaked lime or hydrated lime. It is used for cement, increasing the pH in soils, and water treatment. Lime may be obtained from building material stores in the cement section and in agricultural stores. The smallest quantities sold are generally 5- or 10-pound bags, which cost a few dollars. Because only a teaspoon of lime is needed (the solubility of calcium hydroxide in water is 0. Ig per 100 mL), ask the sales clerk if there are any broken bags from which you can take a tablespoon of lime. Often there will be enough lime dust where it is stored to obtain an ample amount for this activity. 

Other sources of "background" cancer are trace levels of chemicals found in drinking water, food, building materials, and common activities. Such exposures are not natural, but they are ubiquitous because they are associated with elements of modern life that most people deem essential. For example, some of the chlorine used to chlorinate public drinking water forms chloroform. Vapors from dry-cleaned clothes (tetra- and trichloroethylene) mix with the air in closets. Building materials contain formaldehyde. Dioxins, furans, and PCBs are found in the food chain. 

In the indoor environment, sources that can contribute to the VOC levels include building materials, occupants and their activities, ventilation systems and outdoor vehicular combustibles (Daisey et al., 1994 Molhave and Thorsten, 1991). Computations of indoor-outdoor ratios are frequently used to conclude indoor or outdoor sources (Daisey et al, 1994). Generally, derived findings originated from these samples collected when the ventilation systems were in operation. It is difficult to determine the major source of VOCs for the buildings studied because contributions from building materials, occupants and their activities, ventilation systems and outdoors are all present together. 

I building materials I ventilation systems occupants and their activities... 

Phenolic compounds are used in commercial or consumer products or building materials (Rudel et al., 2001), especially ethoxylated alkylphenols of octylphenol and nonylphenol, which are widely used in surfactants (Ying, Williams and Kookana, 2002). They are known as endocrine disrupting compounds (EDC) as they bear hormonally active properties. Other EDCs found indoors include phthal-ates (Section 11.2.7), certain pesticides, organotin compounds (Section 11.2.5) and polybrominated diphenyl ethers (Section 11.2.8) (Rudel et al., 2001, 2003). 

The spectrum of human activities that is related to VOC emissions is wide. Wolkoff (1995) pointed out that the variety of VOC classes associated with these activities is even greater than that associated with emissions from building materials. His publication summarized 17 selected examples of human activities and related VOC emissions from 37 references. Furthermore, Wolkoff (1995) referred... 

Typical activities of building materials, such as bricks and concrete, in the UK and USA are in a similar range (20 to 50 Bq kg-1) (Nero, 1983), but granite used in older houses in Cornwall has about 100 Bq kg -1 of radium (O Riordan et al., 1982). In Sweden, Hultqvist (1956) found about 1000 Bq kg-1 radium equivalent gamma activity in lightweight concrete made from alum shale. 

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