出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/10/16 18:16:59」(JST)
Sick building syndrome (SBS) is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. A 1984 World Health Organization report suggested up to 30% of new and remodeled buildings worldwide may be subject of complaints related to poor indoor air quality.[1]
Sick building causes are frequently pinned down to flaws in the heating, ventilation, and air conditioning (HVAC) systems. Other causes have been attributed to contaminants produced by outgassing of some types of building materials, volatile organic compounds (VOC), molds (see mold health issues), improper exhaust ventilation of ozone (byproduct of some office machinery), light industrial chemicals used within, or lack of adequate fresh-air intake/air filtration (see Minimum Efficiency Reporting Value).
Human exposure to bioaerosols has been documented to give rise to a variety of adverse health effects.[2] Building occupants complain of symptoms such as sensory irritation of the eyes,[3] nose, throat; neurotoxic or general health problems; skin irritation; nonspecific hypersensitivity reactions; infectious diseases;[4] and odor and taste sensations.[5]
Extrinsic alergic alveolitis has been associated with the presence of fungi and bacteria in the moist air of residential houses and commercial offices.[6]
The World Health Organization has classified the reported symptoms into broad categories, including: mucous membrane irritation (eye, nose, and throat irritation), neurotoxic effects (headaches, fatigue, and irritability), asthma and asthma-like symptoms (chest tightness and wheezing), skin dryness and irritation, gastrointestinal complaints and more.[7]
Several sick occupants may report individual symptoms which do not appear to be connected. The key to discovery is the increased incidence of illnesses in general with onset or exacerbation within a fairly close time frame—usually within a period of weeks. In most cases, SBS symptoms will be relieved soon after the occupants leave the particular room or zone.[8] However, there can be lingering effects of various neurotoxins, which may not clear up when the occupant leaves the building. In some cases—particularly in sensitive individuals—there can be long-term health effects.
One large study found no significant relation between most aspects of the physical work environment and symptom prevalence.[9]
Greater effects were found with features of the psychosocial work environment including high job demands and low support. The report concluded that the physical environment of office buildings appears to be less important than features of the psychosocial work environment in explaining differences in the prevalence of symptoms.
Research has shown that SBS shares several symptoms common in other conditions thought to be at least partially caused by psychosomatic tendencies. The umbrella term 'autoimmune (auto-inflammatory) syndrome induced by adjuvants' has been suggested. Other members of the suggested group include Siliconosis, Macrophagic myofascitis, The Gulf War syndrome, Post-vaccination phenomena.[10]
Excessive work stress or dissatisfaction, poor interpersonal relationships and poor communication are often seen to be associated with SBS, recent studies show that a combination of environmental sensitivity and stress can greatly contribute to Sick Building Syndrome.
Sick Building Syndrome is a controversial subject as the majority of recent studies suggest that psychological factors play a large role in psychosomatic symptoms known as Sick Building Syndrome(SBS).
Sick Building Syndrome has been suggested it could be caused by inadequate ventilation, chemical contaminants from indoor or outdoor sources, and/or biological contaminants. Many volatile organic compounds, which are considered chemical contaminants, can cause acute effects on the occupants of a building. "Bacteria, molds, pollen, and viruses are types of biological contaminants" and can all cause SBS. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recently revised its ventilation standard, ASHRAE Standard 62.1-2013 Ventilation for Acceptable Indoor Air Quality (Tables 6.2.2.2.1) reduces previous minimum of 15 cfm of outdoor air per person (20 cfm/person in office spaces) to 10 CFM per classroom person and 5 CFM per office occupant. The five CFM per office person correlates with a predicted carbon dioxide 5.000 PPM occupancy level set by OSHA and adopted for federal workplaces and regulated energy policy during the late 1980s energy scarcity years. In addition, pollution from outdoors, such as motor vehicle exhaust, can contribute to SBS.[1] ASHRAE has recognized that polluted Urban Air, designated within EPA Air Quality ratings as unacceptable requires the installation of gas phase filtration for which the HVAC practitioners generally apply carbon impreganated filters and their like. ASHRAE alleges that excessive energy is used to comply with its previous issues of the referenced IAQ Standard which coupled with improvements in furnishings, finishes and cleaning materials allow for these surprising reductions in fresh air ventilation rates.[11]
There might be a gender difference in reporting rates of sick building syndrome because women tend to report more symptoms than men do. Along with this, some studies have found that women have a more responsive immune system and are more prone to mucosal dryness and facial erythema. Also, women are alleged by some to be more exposed to indoor environmental factors because they have a greater tendency to have clerical jobs, wherein they are exposed to unique office equipment and materials (example: blueprint machines), whereas men often have jobs based outside of offices.[15]
In the late 1970s, it was noted that nonspecific symptoms were reported by tenants in newly constructed homes, offices, and nurseries. In media it was called "office illness”. "The term "Sick Building Syndrome" was coined by WHO in 1986, when they also estimated that 10-30% of newly built office buildings in the West had indoor air problems. Early Danish and British studies reported symptoms.
Poor indoor environments attracted attention. The Swedish allergy study (SOU 1989:76) designated "sick building" as a cause of the allergy epidemic as was feared. In the 1990s, therefore, extensive research into "sick building" was carried out. Various physical and chemical factors in the buildings were examined on a broad front.
The problem was highlighted increasingly in media and was described as a "ticking time bomb". Many studies were performed in individual buildings.
In the 1990s "sick buildings" were contrasted against "healthy buildings". The chemical contents of building materials was highlighted. Many building material manufacturers were actively working to gain control of the chemical content and to replace criticized additives. The ventilation industry advocated above all more well-functioning ventilation. Others perceived ecological construction, natural materials, and simple techniques as a solution.
At the end of the 1990s came an increased distrust of the concept of "sick building". A dissertation at Karolinska Institutet in Stockholm 1999 questioned the methodology of previous research, and a Danish study from 2005 showed these flaws experimentally. It was suggested that Sick Building Syndrome was not really a coherent syndrome and was not a disease to be individually diagnosed. In 2006 the Swedish National Board of Health and Welfare recommended in the medical journal Läkartidningen that "Sick building syndrome" should not be used as a clinical diagnosis. Thereafter, it has become increasingly less common to use terms such as "sick buildings" and "Sick Building Syndrome" in research. However, the concept remains alive in popular culture and is used to designate the set of symptoms related to poor home or work environment engineering. "Sick building" is therefore an expression used especially in the context of workplace health.
Sick building syndrome made a rapid journey from media to courtroom where professional engineers and architects became named defendants and were represented by their respective professional practice insurers. Proceedings invariably relied on expert witnesses, medical and technical experts along with building managers, contractors and manufacturers of finishes and furnishings, testifying as to cause and effect. Most of these actions resulted in sealed settlement agreements, none of these being dramatic. The insurers needed a defense based upon Standards of Professional Practice to meet a court decision that declared—that in a modern, essentially sealed building, the HVAC systems must produce breathing air for suitable human consumption. ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers, currently with over 50,000 international members) undertook the task of codifying its IAQ (Indoor Air Quality) standard.
ASHRAE empirical research determined that “acceptability” was a function of outdoor (fresh air) ventilation rate and used carbon dioxide as an accurate measurement of occupant presence and activity. Building odors and contaminants would be suitably controlled by this dilution methodology. ASHRAE codified a level of 1,000 ppm of carbon dioxide and specified the use of widely available sense-and-control equipment to assure compliance. The 1989 issue of ASHRAE 62.1-1989 published the why’s and wherefores and overrode the 1981 requirements that were aimed at a ventilation level of 5,000 ppm of carbon dioxide, (the OAHA workplace limit), federally set to minimize HVAC system energy consumption. This apparently ended the SBS epidemic.
Over time, building materials changed with respect to emissions potential. Smoking vanished and dramatic improvements in ambient air quality, coupled with code compliant ventilation and maintenance, per ASHRAE standards have all contributed to the acceptability of the indoor air environment. With the publication of ASHRAE 62.1-2013 ASHRAE has reactivated 1981 with respect to ventilation rates. Only time and the courts will tell how right, or wrong ASHRAE is.
[16][17]
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| リンク元 | 「シックハウス症候群」 |
| 拡張検索 | 「sick-building syndrome」 |
| 関連記事 | 「sick」「building」「syndrome」 |