We investigated on the indoor pollution generated from six different heating appliances (three kerosene heaters of different types, town and propane gas heaters and an electric heater) and smoking in the model room (area: 20 m², capacity: 45 m³). Each experiment was conducted under the different 4 type of ventilation conditions described below. 1: Fan off, Door closed, 2: Fan off , Door 45°-open, 3: Fan off, Door 10°-open and 4: Fan on, Door closed. Each heater and smoking were run in the model room for 3 hours, and the concentration of each pollutant was measured for 9 and 6 hours. We measured NO, NO₂, CO, CO₂, HCHO, suspended particulate matter and polycyclic aromatic hydrocarbons (PAH) as indoor pollutants of this study. From these results, we obtained relatively high concentration of NO₂, CO₂, and HCHO from using all heaters without electric heater under the non-ventilation condition. The concentrations of suspended particulate matter and PAH also increased using kerosene- fueled heater. In case of smoking, the concentration of NO, CO, CO₂, HCHO, suspended particulate matter and PAH are increased under the non-ventilation condition. On the other hand, the concentration of these chemicals significantly decreased under the ventilation condition. From these results, ventilating operations were shown to be an effective operation for the decreasing of indoor pollution.

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Basidiomycetes, including Schizophyllum commune, cause mycosis as well as pulmonary aspergillosis. Many basidiomycetes are termed filamentous basidiomycetes because they form white mycelia colonies on the medium. There are many unclear points on the situation of airborne filamentous basidiomycetes in general houses. In order to clarify the exposure situation of basidiomycetes, the airborne white filamentous basidiomycetes in 20 general houses was investigated. We sampled airborne fungi from the bedrooms and adjacent balconies throughout 4 seasons from autumn 2016 to summer 2017. Identification of isolated filamentous basidiomycetes was performed by DNA sequence analysis of the ITS region. As a result of this study, 29 strains of filamentous basidiomycetes in autumn, 7 strains in winter, 23 strains in spring and 49 strains in summer were isolated from bedrooms. The highest isolates were 38 strains of Trametes hirsuta followed by 12 strains of Trametes lactinea. The number of isolated S. commune was 10 strains. It was indicated that basidiomycete had the seasonality in the diffusion time of spore depending on the species. This survey revealed one of the conditions of airborne white filamentous basidiomycetes in the indoor air of general houses.

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Various experimental researches have been conducted recently on Semivolatile organic compounds (SVOC) in house dust. Those emission souces would be plasticizers and flame retardants used in products. Part of substances of plasticizers and flame retardants are subject to various restrictions due to concerns about human health. Since SVOCs have low vapor pressure and high adsorptivity, those exist not only as gas phase but also as particle phase and house dust phase in indoor environments. Those measurement processes would be technically complicated. Therefore, we focused on those transfer routes and estimated SVOC concentration in house dust with phase partitioning models. For plasticizers and brominated flame retardants, estimated values were obtained on the safety side of factor 1.78-13.1 (med.). Those slopes of regression lines were 0.838-1.28, which were close to 1. From a macroscopic viewpoint, these models can practically predict SVOC concentrations in house dust. Whereas estimated values for organophosphate flame retardants with LogK_oa less than about 10 were underestimated by 2 orders of magnitude. These would be caused by existence of other transfer routes or differences between K_oa and actual partitioning coefficient.

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Acetaldehyde is known to cause indoor air pollution of a living space. Though numerous emission sources of acetaldehyde have been previously reported in relation to indoor air quality, little consideration has been given to the influence of household refrigerator. Since considerable levels of acetaldehyde was previously found in the inner space of refrigerators, air leakage from inside air can be a potential source of acetaldehyde in indoor air of a living space. This study aimed to estimate contribution of acetaldehyde leaked from a household refrigerator to indoor air concentration in the living space based on distributions of inner concentration levels and air exchange rates of domestic refrigerators employing Monte Carlo method with 10,000 trials. The mean indoor air concentration of acetaldehyde in the living space resulted in 0.12 ug/m³ for a single life, and 0.67 ug/m³ for a family consisting of at least two members, which were much less than the odor threshold of acetaldehyde (2.7 g/m³) and indoor air quality guideline level (48 g/m³). The results showed the air leakage from the household refrigerator is not a significant factor for the air contamination by acetaldehyde. However, we should keep concern on the refrigerator as a potential source of chemicals other than acetaldehyde.

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Measurement of volatile organic compounds (VOCs) using the passive sampling method have received increasing attention owing to their simplicity and ease of use. However, there are still few applications of passive samplers for high-boiling point VOCs. The Japanese Health, Labor and Welfare Ministry is discussing new standards for indoor concentration levels of three substances (new guideline VOCs): 2-ethyl-1-hexanol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Texanol) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). Texanol and TXIB have higher-boiling points than general VOCs. Obtaining accurate sampling rates (SRs) of the high boiling point VOCs is an issue in establishing passive sampling methods. In this study, we investigated the control method of generating sufficient concentrations of these VOCs in an exposure chamber to obtain accurate SRs of Texanol and TXIB. The obtained SRs for investigated VOCs were in the range of approximately 10-200% of the prescribed guideline value concentration. The reproducibility of the exposure test was high and the coefficients of variation of the exposure tests conducted under each exposure conditions were less than 10%. For sampling in a prefabricated house, the values calculated using the passive sampling method and the obtained SRs were equivalent to those using the active sampling method. Therefore, measuring new guideline VOCs using this passive air sampler method is feasible.

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Nursing home have been found to play a significant role in the spread of Antimicrobial Resistant Organisms (AMROs). However, only few reports have elucidated the isolation of resistant bacteria and risk factors for the carriage such bacteria in these facilities. This study examined the situation of the carriage of AMROs in a special unit-type nursing home (Facility A). The residents of Facility A mainly live in their own rooms. The study also analyzed the risk factors of bacterial carriage among the residents of Facility A based on their attributes. We obtained consent for study participation from 28 residents. Certain resistant bacteria were detected in 10 participants (35.7%). Of these bacteria, Methicillin-resistant Staphylococcus aureus (MRSA) was detected in one participant (3.6%) and glucose non-fermenting bacteria, which grew in a culture medium selective for Extended-Spectrum β-lactamase (ESBL), were detected in two participants (7.1%). The bacterial carriage rate among participants of Care Level 4 or above was 53.8%, which was higher than that of participants of Care Level 3 or below (20.0%). No statistically significant difference (p = 0.06, chi-square test) was found between the two groups. Additionally, a comparison of bacterial carriage rates between participants who require assistance for everyday activity and those who do not revealed that the rates were higher in those who required assistance for eating, excretion, and moving between the bed and wheelchair. The difference observed was not significant. This study did not find significant difference for any risk factors. However, we deem that future studies are needed in larger cohorts and in a larger number of facilities. In doing so, the characteristics of facilities should be considered.

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In this study, a method for measuring acrylamide in indoor air was investigated, wherein, gaseous acrylamide present in the indoor air was collected in an activated carbon sampler and, extracted with methanol, followed by GC/MS measurements. In this report, we describe the extraction method, collection efficiency, reproducibility test, storage stability, etc. In order to detect acrylamide present in indoor air, an ultrasonic extraction method was employed, where the extraction time was 10 min and the collection efficiency with one collection tube was 95% or more. The repeatability was 4.6% in relative standard deviation the lower limit of quantification was 11.9 ng/m³(1 L/min x 24 hours, 1440 L sampling). The storage stability of acrylamide in the sampler was observed to be stable for 10 days at room temperature. Consequently, it could be inferred that gaseous acrylamide was not present in the indoor environment of general households. However, 23 ng/m³ of acrylamide was detected when mosquito coils were used indoors, and 116-6133 ng/m³ of acrylamide was detected when people smoked indoors place cigarette.

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I investigated the fungi on the surface of concrete walls in the indoor or semi-indoor environment. On the wall of a semi-indoor underground parking lot, Cladosporium was most frequently detected, and very slow-growing fungus identified as Devriesia was sometimes detected. Aspergillus and Engyodontium were often detected as dominant species on concrete walls where the environment is likely to be humid and condensation occurs. When the spore scattering properties were examined on the concrete wall where the propagation of Cladosporium was confirmed, no scattering occurred with a slight wind (wind velocity; 2-3 m/s), but scattering was observed due to water spraying or physical rubbing event. The number of fungi on the concrete wall increased in summer when the difference between the wall surface temperature and the air temperature increased. In the removal of fungi on the concrete walls, washing with alcohol or hypochlorous acid based detergent was more effective in elimination and the effects continued longer than washing with water. Antifungal effect on the fungi by some fungicides was recognized even after 3 years of treatment, but it was confirmed that the effect faded after 6 years.

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Environmental intolerance (EI) is a chronic acquired disorder characterized by non-specific and recurrent multisystem symptoms attributed to low levels of chemical, biologic, or physical agents. Multiple chemical sensitivity (MCS) or chemical intolerance (CI) is one of the EI. This review presents the suggested mode of action, pathophysiology, epidemiology, and extrinsic environmental factors for preventing MCS/CI. Patients with MCS process odors differently from healthy controls. Several studies suggested that patients with MCS were demonstrated to peculiarly react to sensory stimuli, with activation of brain areas connected with motivational and emotional processing of the information. These brain responses may involve cognitive and memory processing systems during past exposure event to harmful chemicals. A 5-year follow-up epidemiological study indicated that the baseline negative psychosomatic states, including irritability, fatigue, anxiety, depressed mood, and somatic symptoms were associated with development of CI in controls. Appropriate physical activity and maintaining a regular lifestyle, including diet or sleep, were factors for improvement of CI in the CI group. Stable psychosomatic state is essential for preventing CI. Multiple extrinsic environmental factors involve the onset of MCS/CI and the exposure events are different in patients with MCS. In particular, information on the exposure concentration is very limited. Many countries including Japan have developed air quality guidelines or standards in indoor, ambient, or occupational environment. These provide a uniform basis for protecting public health from the adverse effects of air pollution, and to eliminate or reduce to a minimum exposure to those pollutants that are known or are likely to be hazardous to human health. Furthermore, these guidelines or standards can serve to limiting emissions, especially those of materials, products, or industrial activities. These guidelines or standards will play an important role in preventing the onset of MCS/CI. Continuous assessment and management in indoor, ambient, and occupational environment are required.

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Mobile telecommunication and internet technologies have been rapidly developed during last two decades. Concomitantly, the number of people is growing, who suffer from electromagnetic hypersensitivity (EHS). Hence, a causal relation between the electromagnetic waves and EHS has been suspected. International Commission on Non-Ionizing Radiation Protection (CNIRP) set a limit of the exposure to electromagnetic waves. However, the limit is based on the physiological limit that has been derived from the physically accepted interaction of the electromagnetic waves and the human body. Thus, the limit is three orders of magnitude higher than the level above which the patients of EHS normally develop their symptoms. The prevailing view is that humans do not feel magnetic fields that are lower than the above limit. Hence, the principle of the setting of the limit has not been questioned. However, some species such as bacteria, birds, reptiles and fishes seem to possess geomagnetic sense and utilize it for navigation. In this commentary, I will first explain how the limiting values for the electromagnetic waves have been determined and then briefly explain geomagnetic sense of bacteria and that of homing pigeons. It turned out that these sensing mechanisms cannot detect the magnetic field that has been attributed to the cause of EHS. Thus, I will explain a recently proposed hypothesis based on the interaction between radicals and the local magnetic fields (= geomagnetic field + time-varying magnetic field originated from the electromagnetic wave). It has been hypothesized that the precession of the radical in the local magnetic field is highly sensitive to the presence of the time-varying component in the local magnetic field, and even the time-varying magnetic field of less than 1 microtesla can modulate the chemical reaction that involves the radical.

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Multiple chemical sensitivity (MCS), also known as environmental intolerance, has been described as a chronic acquired disorder characterized by nonspecific symptoms in multiple organ systems and is associated with exposure to low-level chemicals. In this paper, I describe the current status of MCS in relation to industrial health in Japan, with regard to the following three points: 1) changes of MCS prevalence rate within three companies using a Questionnaire (Quick Environment Exposure Sensitivity Inventory (QEESI)) over the past 12 years. 2) current status of law on chemical substance and accreditation of occupational accidents. 3) court judgments on MCS that have occurred in work environments.

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