Chemical indoors

Chemical and biological evaluation of building material emissions. II. Approaches for setting indoor air standards or guidelines for chemicals. Indoor Air, 7, 17-32. 

Multiple chemical sensitivity (MCS) or multiple chemical intolerance (MCI) is a term used to describe a variety of symptoms associated, in some cases, with exposure to indoor air contaminants. Individuals with this syndrome seem to respond to very low levels of chemicals, and the condition can involve various organ systems. It appears to be induced by a wide variety of agents, but once induced it can be triggered by low-concentration exposures to numerous other chemicals. Indoor air pollutants not only appear to set off symptoms in the chemically intolerant, but several studies suggest that some pollutants or pollutant mixtures may also initiate the condition. This phenomenon has been described in... 

Fitzner and Finke, 1996), nonetheless the TVOC concept seems to be appropriate to establish a general indicator for an acceptable (chemical) indoor climate. 

Nielsen G.D., Hansen L.F., Wolkoff P, (1997) Chemical and Biological Evaluation of Building Material Emissions. II. Approaches for Setting Indoor Air Standards or Guidelines for Chemicals. Indoor Air 7, 17-32. 

Manufacturers Comments RT curing. Thin-bed mortar for joining and laying ceramic coverings in areas with high loads, Inc. under-floor heated. Resistant to water and chemicals. Indoor and outdoor use. ... 

Steam-Generating Facilities These form the second largest investment item for chemical-plant auxiliaiy equipment. Variations in capacity, location indoors or outdoors, the type of fuel used, pressure and temperature levels, and the type of process served have an important effect on actual cost as well as on cost relative to other auxiliaiy items. Package boiler instaUations can be purchased as shop-built units which are assembled, piped, and wired ready to be erected on the owner s foundations. They are available in units up to about 136,000 kg/h (300,000 Ib/h), although units larger than about 45,360... 

These transformers may be PVC taped, thermoplastic (polypropylene) moulded, fibreglass taped, polyester resin cast or epoxy resin cast depending upon the system voltage and the surroundings. HT indoor transformers, for instance, are generally polyester or epoxy resin cast, and are economical with good dielectric properties. They are resistant to humid, chemically contaminated and hazardous areas. Outdoor HT transformers, how-ever. may be epoxy... 

Storage of catalyst and chemicals must be decided— some will be indoors and some perhaps outdoors. Tankage will be provided for treating chemicals, such as MEA, for holding process inventoiy for turnarounds. 

In the first environment, we are concerned with the potential health risks that chemicals pose to the public, as well as possible impacts on the ecology. In the latter case, we are concerned with indoor air quality and its possible adverse impacts on the health and safety of the workforce. In both cases the health dangers may be either acute, or long-term chronic health risks. We will first discuss general concepts of air pollution and table our discussions on... 

In nonindustrial settings, MCS substances are the cause of indoor air pollution and are the contaminants in air and water. Many of the chemicals which trigger MCS symptoms are known to be irritants or toxic to the nervous system. As an example, volatile organic compounds readily evaporate into the air at room temperature. Permitted airborne levels of such contaminants can still make ordinary people sick. When the human body is assaulted with levels of toxic chemicals that it cannot safely process, it is likely that at some point an individual will become ill. For some, the outcome could be cancer or reproductive damage. Others may become hypersensitive to these chemicals or develop other chronic disorders, while some people may not experience any noticeable health effects. Even where high levels of exposure occur, generally only a small percentage of people become chemically sensitive. 

A small percentage of the population may be sensitive to a number of chemicals in indoor air, each of which may occur at very low concentrations. The existence of this condition, which is known as multiple chemical sensitivity (MCS), is a matter of considerable controversy. MCS is not currently recognized by the major medical organizations. Medical opinion is divided, and further research is needed. The applicability of access for the disabled and worker s compensation regulations to... 

Indoor air quality complaints can arise from inadequate housekeeping that fails to remove dust and other dirt. On the other hand, cleaning materials themselves produce odors and emit a variety of chemicals. As they work throughout a building, cleaning staff or contractors may be the first to recognize and respond to potential lAQ problems. 

Measurement of specific chemical or biological contaminants can be very expensive. Before expending time and money to obtain measurements of indoor air pollutants, you must decide how the results will be used (e.g., comparison to standards or guidelines, comparison to levels in complaint-free areas) what substances(s) should be measured where to take, samples when to take samples what sampling and analysis method to use so that the results provide useful information. 

Organic Compounds Chemicals that contain carbon. Volatile organic compounds vaporize at room temperature and pressure. They are found in many indoor sources, including many common household products and building materials. 

The models in the THERdbASE CD are Chemical Source Release, Instantaneous Emission, Chemical Source Release, Timed Application, Indoor Air (2-Zone), Indoor Air (N-Zone), Exposure Patterns for Chemical Agents, Benzene Exposure Assessment Model (BEAM), Source Ba.sed Exposure Scenario (Inhalation + Dermal), and Film Thickness Based Dermal Dose. 

Occupational and environmental exposure to chemicals can take place both indoors and outdoors. Occupational exposure is caused by the chemicals that are used and produced indoors in industrial plants, whereas nonoccupa-tional (and occupational nonindustrial) indoor exposure is mainly caused by products. Toluene in printing plants and styrene in the reinforced plastic industry are typical examples of the two types of industrial occupational exposures. Products containing styrene polymers may release the styrene monomer into indoor air in the nonindustrial environment for a long time. Formaldehyde is another typical indoor pollutant. The source of formaldehyde is the resins used in the production process. During accidents, occupational and environmental exposures may occur simultaneously. Years ago, dioxin was formed as a byproduct of production of phenoxy acid herbicides. An explosion in a factory in... 

The setting of indoor air quality targets is much more complicated and individualized, T his is due to the fact that the chemical process in paper making differs from paper type to paper type. Also, the amount of particles is highly dependent on the speed of the machine, the percentage of recycled mass, and the percentage of stone in the paper. 

In the case of gaseous contaminants, the tracer gas is selected to simu late as well as possible the properties (density, temperature) and momentum of the real contaminant. It is essential to ensure that the tracers arc nontoxic, chemically nonreactive, nonadsorptive on indoor surfaces, and inexpensive. The mixing of the tracer with the actual gaseous contaminant before its release or the release of the tracer with a density near that of the air will improve the validity of the simulation. With tracers, the most difficult task in practice is the relationship of the discharge between the tracer and the real contaminant. Case-by-case techniques to release the tracer are necessary in practice. With tracer gases, the procedure for capture efficiency is described in detail in the European Standard. - The tracer gas concentrations are measured in the exhaust duct for two release locations as illustrated in Fig. 10.108. 

Problems that rank relatively high in cancer and non-cancer health risks but low in ecological and welfare risks include hazardous air pollutants, indoor radon, indoor air pollution other than radon, pesticide application, exposure to consumer products, and worker exposures to chemicals... 

Environmental tobacco smoke (ETS) is the diluted mixture of pollutants caused by smoking of tobacco and emitted into the indoor air by a smoker. Constituents of ETS include submicron-size particles composed of a large number of chemicals, plus a large number of gaseous pollutants. Fibers in indoor air include those of asbestos, and man-made mineral fibers such as fiberglass, and glass wool. 

Some particles and fibers may be generated by indoor equipment (e.g. copy machines and printers). Mechanical abrasion and air motion may cause particle release from indoor materials. Particles are also produced by people, e.g., skin flakes are shed and droplet nuclei are generated from sneezing and coughing. Some particles may contain toxic chemicals. 

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