Naoki Kagi

Prevalence and risk factors associated with nonspecific building-related symptoms in office employees in Japan: relationships between work environment, Indoor Air Quality, and occupational stress.

A nationwide cross-sectional study of 3335 employees was conducted in 320 offices in Japan to estimate the prevalence of building-related symptoms (BRSs) and determine the risk factors related to work environment, Indoor Air Quality, and occupational stress. Data were collected through self-administered questionnaires. The prevalences of general symptoms, eye irritation, and upper respiratory symptoms were 14.4%, 12.1%, and 8.9%, respectively. Multiple logistic regression analyses revealed that eye irritation was significantly associated with carpeting [odds ratio (OR), 1.73; 95% confidence interval (CI), 1.24-2.41], coldness perception (OR, 1.28; 95% CI, 1.13-1.45), and air dryness perception (OR, 1.61; 95% CI, 1.42-1.82). General symptoms were significantly associated with unpleasant odors (OR, 1.37; 95% CI, 1.13-1.65), amount of work (OR, 1.24; 95% CI, 1.06-1.45), and interpersonal conflicts (OR, 1.44; 95% CI, 1.23-1.69). Upper respiratory symptoms were significantly associated with crowded workspaces (OR, 1.36; 95% CI, 1.13-1.63), air dryness perception (OR, 2.07; 95% CI, 1.79-2.38), and reported dustiness on the floor (OR, 1.39; 95% CI, 1.16-1.67). Although psychosocial support is important to reduce and control BRSs, maintaining appropriate air-conditioning and a clean and uncrowded workspace is of equal importance.

Effects of water-damaged homes after flooding: health status of the residents and the environmental risk factors

We evaluated the health status of residents and the environmental risk factors of housing after flooding. Questionnaires were distributed to 595 selected households (one adult resident per household) in six areas in Japan which were severely flooded between 2004 and 2010. A total of 379 responses were obtained. Indoor dampness and visible mold growth significantly increased in homes with greater flood damage. The incidence of respiratory, dermal, ocular, and nasal symptoms one week after flooding was significantly higher in flooded homes compared with non-flooded homes, the incidence of psychological disorders was significantly high for six months after flooding, and the incidence of post-traumatic stress disorder was significantly high six months after flooding. Significant risk factors for respiratory and nasal symptoms included proximity to industrial and waste incineration plants. Our results suggest that rapid action should be taken after flooding to ensure adequate public health and environmental hygiene in the water-damaged homes.

Indoor air quality and thermal comfort in temporary houses occupied after the Great East Japan Earthquake.

UNLABELLED Thermal conditions and indoor concentrations of aldehydes, volatile organic compounds (VOCs), and NO2 were investigated in 19 occupied temporary houses in 15 temporary housing estates constructed in Minamisoma City, Fukushima, Japan. The data were collected in winter, spring, and summer in January to July 2012. Thermal conditions in temporary log houses in the summer were more comfortable than those in pre-fabricated houses. In the winter, the indoor temperature was uncomfortably low in all of the houses, particularly the temporary log houses. Indoor air concentrations for most aldehydes and VOCs were much lower than the indoor guidelines, except for those of p-dichlorobenzene, acetaldehyde, and total VOCs. The indoor p-dichlorobenzene concentrations exceeded the guideline (240 μg/m(3)) in 18% of the temporary houses, and the 10(-3) cancer risk level (91 μg/m(3)) was exceeded in winter in 21% due to use of moth repellents by the occupants. Indoor acetaldehyde concentrations exceeded the guideline (48 μg/m(3) ) in about half of the temporary houses, likely originating from the wooden building materials. Indoor NO2 concentrations in the temporary houses were significantly higher in houses where combustion heating appliances were used (0.17 ± 0.11 ppm) than in those where they were not used (0.0094 ± 0.0065 ppm). PRACTICAL IMPLICATIONS In the winter, log-house-type temporary houses are comfortable in terms of humidity, dew condensation, and fungi based on the results of questionnaires and measurements, whereas pre-fabricated temporary houses are more comfortable in terms of temperature. In the summer, log-house-type temporary houses are comfortable in terms of temperature and humidity. More comfortable temporary housing in terms of temperature and humidity year-round is needed. Indoor air concentrations of p-dichlorobenzene and NO2 were quite high in some temporary houses due to occupants’ activities, such as use of moth repellents and combustion heating appliances. The government should provide recommendations for safe use of temporary houses by occupants.

Evaluating prevalence and risk factors of building-related symptoms among office workers: Seasonal characteristics of symptoms and psychosocial and physical environmental factors

BackgroundPsychosocial and environmental factors at the workplace play a significant role in building-related symptoms (BRSs). Environmental factors change during summer cooling and winter heating using air-conditioning systems. Thus, significant risk factors in each season need to be clarified.MethodsA nationwide cross-sectional study was conducted during summer in Japan and seasonal differences between summer and winter were evaluated. Self-administered questionnaires were distributed to 489 offices. Possible risk factors for BRSs associated with the work environment, indoor air quality, and job stressors were examined by multiple regression analyses.ResultsAmong people having at least one BRS, the prevalence of BRSs in summer (27.8%) was slightly higher than that in winter (24.9%). High prevalence was observed for eye and nasal symptoms related to dryness and general symptoms related to psychological distress in both seasons. Analyses revealed that dryness of air was an important and significant risk factor associated with BRSs, and job stressors were significantly associated with general symptoms in both seasons. Conversely, humidity was a significant risk factor of general symptoms in summer (odds ratio, 1.20; 95% confidence interval, 1.02–1.43). Carpeting, recently painted walls, and unpleasant chemical odors in summer and noise, dust and dirt, and unpleasant odors such as body or food odors in both seasons were significant risk factors for BRSs.ConclusionsImprovements in the physical environmental qualities in an office throughout the year are important along with the reduction in psychological distress related to work.

Study of the different Cutoff Point of the QEESI Questionnaire as a Screening Tool for Sick Building Syndrome Diagnosis in Taiwan

Abstract The Indoor Air Quality Management Act in Taiwan formally came into effect in November 2012 to protect public health. Studies have reported that public and private buildings in Taiwan currently have been facing pollution problems regarding indoor air quality (IAQ), which threatens the health of occupants.1), 2) To clarify the correlation between the indoor air environment and influences on human health by using an economical and efficient method, the United States, Japan, and other countries use screening tools first to understand the health effects on building occupants, and, subsequently, adopt appropriate examination methods once primary influential factors are identified. To enable the integration of research results from Taiwan with those from abroad, this study introduced the quick environmental exposure and sensitivity inventory (QEESI) questionnaire, which the United States, Japan, and other countries have implemented for many years. In this study, the applicability of the QEESI questionnaire in screening sick building syndrome (SBS) in Taiwan was examined by observing the association between the QEESI score and IAQ survey results. The results from Taiwan were compared with those from the United States and Japan. A questionnaire concerning personal and residential environmental factors was also incorporated to identify factors with significant predictive power for the QEESI score. The following conclusions were derived from this study. 1. The correlation between the IAQ survey values and the QEESI score indicates the capability of the QEESI questionnaire to identify problems related to sick buildings and to serve as a screening tool for SBS in Taiwan. 2. Currently, using the cutoff points proposed by Japanese researchers3-5) to judge the QEESI score can optimally enhance the correlation between the IAQ survey results and the QEESI scores for people in Taiwan. 3. Eight factors with significant predictively power for the QEESI score include gender, age, an understanding of the mechanism of SBS occurrence, allergy history, building type, air ventilation, the use of deodorants and fragrances, and smoking. These factors can serve as key points when performing on-site examinations.

Physicochemical risk factors for building-related symptoms in air-conditioned office buildings: Ambient particles and combined exposure to indoor air pollutants

We conducted a cross-sectional epidemiological study to examine the correlation between indoor air quality (IAQ) and building-related symptoms (BRSs) of office workers in air-conditioned office buildings. We investigated 11 offices during winter and 13 offices during summer in 17 buildings with air-conditioning systems in Tokyo, Osaka, and Fukuoka, and we included 107 office workers during winter and 207 office workers during summer. We conducted environmental sampling for evaluating IAQ and concurrently administered self-reported questionnaires to collect information regarding work-related symptoms. Multivariate analyses revealed that upper respiratory symptoms showed a significant correlation with increased indoor temperature [odds ratio (OR), 1.55; 95% confidence interval (CI), 1.11-2.18] and increased indoor concentration of suspended particles released from the ambient air pollution via air-conditioning systems (OR, 1.31; 95% CI, 1.08-1.59) during winter. In particular, smaller particles (particle size>0.3μm), which possibly penetrated through the filter media in air-conditioning systems from ambient air, were correlated with upper respiratory symptoms. The use of high-efficiency particulate air filters in air-conditioning systems and their adequate maintenance may be an urgent solution for reducing the indoor air concentration of submicron particles. Several irritating volatile organic compounds (VOCs) (e.g., formaldehyde, acetaldehyde, ethylbenzene, toluene, and xylenes) that were positively correlated with the indoor air concentration among their VOCs, were associated with upper respiratory symptoms, although their indoor air concentrations were lower than those specified by the indoor air quality guideline. A new approach and strategy for decreasing the potential combined health risks (i.e., additive effect of risks) associated with multiple low-level indoor pollutants that have similar hazardous properties are required.

Field Survey on the Relation between IAQ and Occupants' Health in 40 Houses in Southern Taiwan

Abstract Taiwan and Japan are similar in life style and customs. Taiwan is geographically situated in a subtropical climate zone which is deemed as a future model of Japanese climate if global warming continues. It is therefore advantageous for Japanese to know the present IAQ (Indoor Air Quality) situations in Taiwan. The research was carried out in two phases. The first phase used questionnaire surveys to collect the relevant information of the occupants and their living environments, and QEESI questionnaires (Chinese version) for information regarding their health conditions. In the second phase, IAQ measurements were conducted in the 40 houses which were selected among volunteers of the first survey. Measurement items were temperature, humidity and concentrations of carbonyl compounds and VOCs (Volatile Organic Compounds). Verification measurements were conducted to investigate the hypothesis in the two houses, A and B, selected from 40 measured houses. The amount of furnishing materials in the two houses was quite different. Finally, the questionnaire results, QEESI (Quick Exposure Sensitivity Inventory) scores, and IAQ data were compared accordingly to determine the factors that cause SHS (Sick House Syndrome). The results are as follows. 1. For areas deficient in SHS and/or MCS (Multiple Chemical Sensitivity) diagnoses, combining QEESI investigations and IAQ measurements in the surveys is successful in screening SH and discovering SHS. 2. To reduce indoor air pollution effectively, it is insufficient just to regulate the materials and the quantity of interior furnishings. Construction process, ventilation rate, airflow path, and an overall plan with strict assessment should all be included in the regulations.

A Study on Indoor Air Contaminants Related to Pets in Japanese Dwellings

Abstract The behavior of indoor particulate matter as it relates to pets was studied from the viewpoint of architectural hygiene. The viable particles from pets can be classified into two types, pathogenic microorganisms and pet allergens. This study investigated Pasteurella, which is a pathogenic organ of Pasteurellosis, dog allergen Can f1 and cat allergen Fel d1 in eight dwellings in Tokyo. In six of these dwellings (the case dwellings), the dogs and/or cats were allowed free access to indoor areas. Pasteurella and the pet allergens were quantified by biochemical and immunological methods, respectively. The relationship between suspended particles and airborne Fel d1 was also examined. Three species, P. canis, P. dagmatis and P. multocida, were isolated from the oral cavity of the dogs and cats. In the six case dwellings, dust allergen Can f1 and Fel d1 ranged from 1 to 1000 μg allergen/g dust and 100 to 5000 μg/g, respectively. The indoor air of the case dwellings contained concentrations of airborne Fel d1 ranging from 10 to 100 ng of allergen/m3 air. In addition, there was a significant relationship between the distributed concentration of suspended particles larger than 5 μm and airborne Fel d1 (P< 0.01). These findings suggest that the traditional reduction method for coarse particles, for example the use of a domestic air filtration cleaner, may be effective in removing airborne pet allergens.

Indoor Environment in Children’s Dwellings in Dalian and Beijing, China

In 2013, field measurements of indoor environments in children’s (from 8 to 12 years old) dwellings were performed in 20 households in Dalian and Beijing to investigate the association between indoor environmental factors and children’s health. This study includes comprehensive factors about indoor environment in children’s dwellings in Dalian and Beijing and the exposure levels of multiple pollutants. The results showed that the indoor thermal environments were similar in Dalian and Bejing. Regarding children’s indoor air quality, indoor PM2.5 in Beijing was more serious than that in Dalian. Dwellings in Dalian have more chemical pollutants than those in Beijing. In addition, Penicillium, Cladosporium, and Aspergillus were found as the main fungi in children’s dwellings. Moverover, indoor thermal comfort in healthy children’s dwellings was better than in unhealthy children’s. The indoor PM2.5 from indoor sources may affect children’s health with regard to respiratory diseases and allergies more than those from outdoor sources. When the concentration of formaldehyde got higher, the relationship between formaldehyde and children’s health was more significant. The other factors were not found to have a significant relation with children’s health.

Effects of low-level inhalation exposure to carbon dioxide in indoor environments: A short review on human health and psychomotor performance

Scientific literature and documents pertaining to the effects of inhalation exposure to carbon dioxide (CO2) on human health and psychomotor performance were reviewed. Linear physiological changes in circulatory, cardiovascular, and autonomic systems on exposure to CO2 at concentrations ranging from 500 to 5000 ppm were evident. Human experimental studies have suggested that short-term CO2 exposure beginning at 1000 ppm affects cognitive performances including decision making and problem resolution. Changes in autonomic systems due to low-level exposure to CO2 may involve these effects. Further research on the long-term effects of low-level CO2 exposure on the autonomic system is required. Numerous epidemiological studies indicate an association between low-level exposure to CO2 beginning at 700 ppm and building-related symptoms. Respiratory symptoms have been indicated in children exposed to indoor CO2 concentrations higher than 1000 ppm. However, other indoor comorbid pollutants are possibly involved in such effects. In the context of significant linear increase of globally ambient CO2 concentration caused by anthropogenic activities and sources, reducing indoor CO2 levels by ventilation with ambient air represents an increase in energy consumption in an air-conditioned building. For the efficient energy control of CO2 intruding a building from ambient air, the rise of atmospheric CO2 concentration needs to be urgently suppressed.