[Review of sick house syndrome]

Home as a new physical workplace: a causal model for understanding the inextricable link between home environment, work productivity, and well-being

The home has become a new physical workplace, and can therefore influence the work, health, and life of workers. This cross-sectional study aimed to evaluate the chronology of the effects of work hazards at home on factors such as workers' health, productivity, and well-being (WB). Information on novice working-from-home (WFH) workers was derived from the "Occupational health of WFH" project. The selected variables in the hypothesis model comprised problems such as perceived indoor environmental quality (IEQ), working conditions (WC), sick house syndrome (SHS), occupational stress (OS), work productivity (WP), and WB. The relationship between these variables was analyzed using a structural equation model. The group analysis results showed the following significant indirect path effects from work environment through WP: IEQ-> SHS->OS->WP. A non-significant direct effect was observed between IEQ and WP. While WC problems could also have a significant direct effect on WP, or be mediated by OS, WP is a significant consequence and a direct effect of WB. In conclusion, the WFH model's causal impact between home environment, WP, and WB is a physiopsychological pathway. Therefore, creating a healthy home environment and WC, along with OS management, comprise important issues for improving productivity and WB for this new work style.

Differential determination of plasticizers and organophosphorus flame retardants in residential indoor air in Japan

A variety of chemicals have been used in a wide range of indoor materials, such as wallpaper and furniture, and some of them are released into the indoor air. The level of consumption as well as the diversity of these chemicals has been increasing. The particle size of the materials in the air is known to affect the depth of human exposure, e.g., particles >10 μm can only reach the nasal cavity, whereas particles 2.5-10 μm can reach the respiratory tract and particles <2.5 μm can reach the bottom of the lungs. However, information on the concentrations and form of these chemicals in indoor air is very limited. In this study, we measured 54 compounds, including plasticizers (phthalates, adipates, and others) and organophosphorus flame retardants, in indoor air samples from the living rooms of 21 dwellings in 11 prefectures across Japan. For sampling, we used a four-stage air sampler (multi-nozzle cascade impactor) equipped with three quartz fiber filters to capture chemical particulates in three size ranges (<2.5, 2.5-10, and >10 μm) and a C₁₈ solid-phase extraction disk to capture chemicals that exist in a gas phase in indoor air. Each of the chemicals in the three particulate phases and single gas phase was extracted by acetone and measured separately using GC/MS. Of the 54 compounds tested, 37 were detected in the indoor air samples. The highest concentration observed was that of 2-ethyl-1-hexanol (5.1 μg/m³), which was detected in samples from all 21 houses. The 37 compounds were captured in the four fractions at different rates roughly based on their molecular sizes. Compounds with a smaller molecular size were commonly detected as a gas phase, whereas compounds with a larger molecular size were detected as one or more of the three particulate phases in the indoor air samples. Among the three particulate phases, many of the compounds were detected from the filter capturing the smallest (<2.5 μm) particles. Therefore, these results suggest that the chemicals measured in this study might penetrate deeply into the lungs as many of them tend to exist as a gas and/or as particles smaller than 2.5 μm.

Sick Building Syndrome Among Junior High School Students in Japan in Relation to the Home and School Environment

Purpose:

There is an increasing concern about sick building syndrome (SBS), especially in Asia. The aim of this study is to investigate associations between SBS and the home, school environment and personal factors among Japanese junior high school students.

Methods:

We investigated students in four junior high schools in Hyogo in Kansai area, Japan. A questionnaire study was performed among students (n=1056), 12-15 years old. Temperature and relative air humidity was measured in the classrooms and dust was collected from the classroom floors and air and was analysed for cat and dog allergens. Associations were analysed by multi-level logistic regression.

Results:

Mucosal symptoms (45.4%), general symptoms (38.9%) and skin symptoms (22.6%) were common. Totally 8.8% reported cat allergy, 6.1% dog allergy, 6.0% mold allergy and 25.7% pollen allergy. Atopy, window pane condensation, floor dampness and odor at home and high relative air humidity in the classrooms were associated with SBS.

Conclusion:

The prevalence of SBS symptoms was high and associated with both home and school environment. Window pane condensation and floor dampness at home can increase the risk for SBS symptoms in students. Moreover high relative air humidity at school may increase the risk for SBS.

Detection of 34 plasticizers and 25 flame retardants in indoor air from houses in Sapporo, Japan

Various plasticizers and flame retardants are contained in building materials and furniture produced for indoor environments. However, some of these material inclusions have been reported to cause endocrine-disrupting and mucosa-irritating effects. Because of the local climate, buildings in Sapporo are better insulated against cold weather than those in many other areas in Japan. In this study, we measured 59 compounds, including plasticizers (phthalates, adipates, and others) and flame retardants (organo-phosphates and brominated compounds), from indoor air samples from six houses in Sapporo. These compounds were measured separately in the gas phase and the particle phase using a two-stage cartridge equipped with a quartz fiber filter (1 μm mesh) and C18 solid-phase extraction disk for sampling and analyzed by GC/MS and LC/MS/MS (for the detection of brominated flame retardants). Among the 59 compounds measured in this study, 34 compounds were detected from the indoor air of the six houses. The highest concentration among the 34 compounds found in a newly built house was 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TXIB) at 20.8 μg/m(3). Di(2-ethyl-1-hexyl)terephthalate (DEHT), which has been used in recent years as an alternative to di(2-ethyl-1-hexyl)phthalate (DEHP), was found in all six houses, although at low concentrations ranging from 0.005 to 0.027 μg/m(3). To our knowledge, this is the first report of DEHT in indoor air in Japan. Among the compounds detected in this study, those with lower molecular weights tended to be captured in the C18 solid-phase extraction disk rather than in the quartz fiber filter. These results suggest that compounds with higher volatility exist preferentially in the gas phase, whereas compounds with lower volatility exist preferentially in the particulate phase in indoor air.

[Association of indoor air quality with physical health of users in a newly built school building in a university]

Several users of a newly built school building in a university (new building) complained about their deteriorating physical health. We measured the air quality in the new building, an old school building and atmosphere in September 2007 and February 2008. We also conducted a questionnaire survey of subjective symptoms of users in the new building in February 2008. The university administrator took some remedial actions to improve the indoor air quality after the first measurement. In September 2007, the concentrations of total volatile organic compounds (TVOCs) and 2-ethyl-1-hexanol in the new building were higher than those in the old building and atmosphere. Moreover, the concentrations of TVOCs exceeded the Japanese recommended guideline values. In February 2008, the concentrations of these substances in the new building were lower than the previous values. Out of the 177 users who were surveyed regarding subjective symptoms, 59 responded to the survey. In September 2007, 21 users felt that their physical health had deteriorated, while in February 2008, 12 users felt no deterioration. However, nine users still complained about the deterioration of their physical health. It was suggested that the improvement in the indoor air quality may be influenced by the decrease in room temperature. Even if the concentrations of VOCs are below the recommended guideline values, users with an enhanced sensitivity towards VOCs may lose their tolerance to low-level VOCs. Our findings suggested that a survey of the changes in the subjective symptoms of users should be conducted to evaluate the improvement in the indoor air quality of newly built buildings.

Study on decomposition of indoor air contaminants by pulsed atmospheric microplasma

Decomposition of formaldehyde (HCHO) by a microplasma reactor in order to improve Indoor Air Quality (IAQ) was achieved. HCHO was removed from air using one pass through reactor treatment (5 L/min). From an initial concentration of HCHO of 0.7 ppm about 96% was removed in one pass treatment using a discharge power of 0.3 W provided by a high voltage amplifier and a Marx Generator with MOSFET switches as pulsed power supplies. Moreover microplasma driven by the Marx Generator did not generate NOx as detected by a chemiluminescence NOx analyzer. In the case of large volume treatment the removal ratio of HCHO (initial concentration: 0.5 ppm) after 60 minutes was 51% at 1.2 kV when using HV amplifier considering also a 41% natural decay ratio of HCHO. The removal ratio was 54% at 1.2 kV when a Marx Generator energized the electrodes with a 44% natural decay ratio after 60 minutes of treatment.

A longitudinal study of aldehydes and volatile organic compounds associated with subjective symptoms related to sick building syndrome in new dwellings in Japan

To determine whether indoor chemicals act as possible environmental risk factors responsible for sick building syndrome (SBS)-related symptoms in new houses (<6 years old) in Japan, we studied 871 people living in 260 single-family houses in 2004 and 2005. We measured the indoor concentrations of aldehydes and volatile organic compounds and longitudinal changes in the living rooms over two consecutive years. Participants answered standardized questionnaires on SBS symptoms and lifestyle habits. Approximately 14% and 12% of subjects were identified as having SBS in the first and second year, respectively. According to analysis adjusted for sex, age, smoking, and allergic diseases, increases in aldehydes and aliphatic hydrocarbons contributed to the occurrence of SBS. Elevated levels of indoor aldehydes and aliphatic hydrocarbons increased the possible risk of SBS in residents living in new houses, indicating that source controls against indoor chemicals are needed to counter SBS.

Relationship between indoor chemical concentrations and subjective symptoms associated with sick building syndrome in newly built houses in Japan

OBJECTIVES

This study explored possible associations between chemical substances and sick building syndrome (SBS)-type symptoms of residents living in new houses in Japan.

METHODS

We randomly sampled 5,709 newly built conventional homes. In the end, 1,479 residents in 425 households completed a questionnaire survey and agreed to environmental monitoring for indoor aldehydes and volatile organic compounds (VOCs) to be conducted in their homes. If the residents had complained about at least one SBS-related symptom, they were classified as suffering from SBS. Multiple logistic regression analysis was used to select predictive chemical factors of SBS symptoms.

RESULTS

About 14% of the subjects suffered from SBS. Many aldehydes and VOCs were associated factors of optical, nasal, and gular symptoms in univariate analysis. After adjustment for other possible risk factors, formaldehyde dose-dependently showed to be a significant risk factor for SBS. Several chemicals had tendency to be associated with SBS symptoms.

CONCLUSIONS

Chemicals detected in Japanese newly built houses tend to increase the risk of subjective symptoms in residents suffering from SBS.

Association between indoor exposure to semi-volatile organic compounds and building-related symptoms among the occupants of residential dwellings

The aim of this study was to evaluate the levels of semi-volatile compounds (SVOCs) in residential detached houses in Sapporo, Japan, and whether exposure to these SVOCs was associated with the development of building-related symptoms named 'sick house syndrome' (SHS). The definition of SHS is fundamentally the same as that of the sick building syndrome (SBS). The presence of symptoms of SHS was evaluated using a validated self-administered questionnaire. Surveys and samplings of air and house dust in 41 dwellings were performed from October 2006 to January 2007, and 134 occupants responded to questionnaires. Samples were analyzed to quantify the concentrations of eight plasticizers, eleven phosphate triester flame retardants, two alkyl phenols used as anti-oxidants, and one organochlorine synergist called s-421, by gas chromatography-mass spectrometry and gas chromatography-flame photometry. The compounds frequently detected were di-n-butylphthalate, di(2-ethylhexyl)phthalate (DEHP), and dibutylhydroxytoluene in air, and DEHP and tris(2-butoxyethyl)phosphate (TBEP) in dust. Tributylphosphate was strongly and directly associated with mucosal symptoms of SHS; s-421 was also directly associated with mucosal symptoms of SHS. On the contrary, some chemicals such as diethylphthalate and TBEP were inversely associated with SHS. In future studies, we plan to assess these associations in a larger population.

PRACTICAL IMPLICATIONS

This study suggests that it may be possible to reduce building-related symptoms by altering exposure to certain SVOCs, such as tributylphosphate commonly found in ceiling and wall coverings and s-421 used as a synergist for pyrethroids. The association between SHS and s-421 suggested that use of pyrethroid insecticides could elicit symptoms of SHS. However, further studies are necessary to test the associations observed in the present study and to examine whether the SVOCs associated with symptoms are causative agents or simply surrogates for some other factor that is causing the symptoms.

A longitudinal study of environmental risk factors for subjective symptoms associated with sick building syndrome in new dwellings

This study was performed to explore possible environmental risk factors, including indoor chemicals, mold, and dust mite allergens, which could cause sick building syndrome (SBS)-type symptoms in new houses. The study was conducted in 2004 and 2005 and the final study population consisted of 86 men and 84 women residing in Okayama, Japan. The indoor concentrations of indoor aldehydes, volatile organic compounds, airborne fungi, and dust mite allergens in their living rooms were measured and the longitudinal changes in two consecutive years were calculated. A standardized questionnaire was used concomitantly to gather information on frequency of SBS-type symptoms and lifestyle habits. About 10% of the subjects suffered from SBS in the both years. Crude analyses indicated tendencies for aldehyde levels to increase frequently and markedly in the newly diseased and ongoing SBS groups. Among the chemical factors and molds examined, increases in benzene and in Aspergillus contributed to the occurrence of SBS in the logistic regression model. Indoor chemicals were the main contributors to subjective symptoms associated with SBS. A preventive strategy designed to lower exposure to indoor chemicals may be able to counter the occurrence of SBS.

[Dampness, biological factors and sick house syndrome]

Sick house syndrome is caused by not only chemicals but also dampness and biological factors. Many European and North American studies have shown that dampness associated with condensation, visible mold, moldy odor, and water-induced damage among others affects residents' health. Recent Japanese studies have also shown a similar significant relationship. Mold can cause infection and allergy, and can produce chemicals such as microbial volatile organic compounds (MVOCs) and (1-->3)-Beta-D-glucan. Mold exposure can be analyzed using culture-based (colony forming unit count) enumeration techniques. More recently, other nonculture-based methods of measuring mold concentrations in indoor environments have been described, which may provide more valid measures of exposure. These are based on measurement of specific mold markers in dust or air, such as ergosterol, genus-specific extracellular polysaccharides or (1-->3)-Beta-D-glucan. Mites are major indoor allergens. The gold standard for measuring exposure to mite allergens is enzyme-linked immunosorbent assay (ELISA), but it is relatively expensive and requires specialized techniques. Several simple semiquantitative dust mites allergen test have b available in Japan.

Regional differences in residential environments and the association of dwellings and residential factors with the sick house syndrome: a nationwide cross-sectional questionnaire study in Japan

This study was conducted to clarify regional differences in residential factors and the association of those factors with dwellings having sick house syndrome (SHS) problems. The survey was conducted in six areas of northern and southern Japan. In terms of regional differences, dampness was not as severe in the dwellings in Sapporo as compared with that in areas in the south. SHS was defined using five categories of nasal, throat and respiratory, skin and general symptoms, which appeared frequently or not frequently and improved upon leaving the home. The dampness index was estimated by the sum of the presence of several indicators: condensation on the window panes and/or wall, visible mold growth, moldy odor, slow-drying wet towels in the bathroom, and water leakage. The dwellings where inhabitants showed any symptoms of SHS comprised 3.7% of all surveyed dwellings. We found significant associations between SHS and dampness index, odors, and stuffiness of the air. For dampness, the adjusted odds ratio (OR) increased with increased dampness index, adjusting for the age of the house, pets indoors, stuffiness of the air, and odors. These results showed an increased risk when several dampness indicators appeared simultaneously.

PRACTICAL IMPLICATIONS

To evaluate the associations of residential environments and Sick House Syndrome (SHS), this cross-sectional questionnaire study was conducted on 2297 dwellings in six areas in Japan from 2003 to 2004. The dwellings where inhabitants showed any of nasal, throat and respiratory, skin and general symptoms comprised 3.7% of all surveyed dwellings, and an increased risk for SHS was found when several dampness indicators, 'condensation', 'visible mold growth', 'moldy odor', 'slow drying wet towels in the bathroom' and 'water leakage', appeared simultaneously.

[Questionnaire survey of workers in specific buildings regarding multiple chemical sensitivity]

OBJECTIVES

The purpose of this study was to investigate the incidence of multiple chemical sensitivity (MCS) and effectiveness of the Quick Environment Exposure and Sensitivity Inventory (QEESI) in Japanese workers in specific buildings.

METHODS

The survey was performed in 2004-2006 in Japan. QEESI (Japanese version) and a checklist on accumulation of fatigue developed by the Ministry of Health, Labour and Welfare were used in the examination of 410 workers in specific buildings. Three criteria of QEESI's "symptom severity", "chemical intolerance", and "other intolerance" were evaluated in this study. Clinical histories were also surveyed.

RESULT

Responses were obtained from 368 (89.8%) workers. The results showed that 132 (35.9%) individuals have been diagnosed as having allergy. Only two (0.5%) individuals were found to be MCS patients. There was no sick building syndrome patient. Applying the "high" criteria with QEESI to the standard of Miller and Ashford, we determined that only four (1.1%) individuals met all the three criteria, and 17 (4.6%) individuals met two of the three criteria. The QEESI score of allergy persons was higher than that of nonallergy persons. Among nonallergy persons, those who have a high score on accumulation of fatigue in the checklist showed a high score in QESSI.

CONCLUSIONS

These findings indicated that the QEESI score tended to increase with workload and be high in individuals with allergy. Therefore, careful consideration is required, when QEESI is applied for screening MCS patients in Japan.