Objective: It is reported that presenteeism costs more than absenteeism. However, it is difficult to measure presenteeism in Japan because there are few available instruments. We examined the reliability and validity of the Japanese version of the Work limitations Questionnaire (the WLQ-J). Methods: We conducted an internet survey with the WLQ-J and Brief Job Stress Questionnaire (BJSQ) of 1,545 males and females working for an IT company and a medical institution (21–61 years of age). The number of employees of the IT company and nursing staff of the medical institution included in the analysis were 373 and 337, respectively (effective response rate: 46.0 %). Results: The subjects’ average age and the ratio of females were 33.2 ± 9.5 yr old and 60.3%, respectively. Factor analysis showed that the number of factors and items of subscales of the WLQ-J accorded with those of the original WLQ. This supports the factorial validity of the WLQ-J. Additionally, sufficient internal consistency was recognized by Cronbach’s alpha (the whole scale=0.97, the subscales=0.88–0.95). Criterion-related validity was supported by the significant dose-response relationship between the subscale scores of the WLQ-J and the stress response of BJSQ as an external criterion (p<0.01). Conclusions: The study results demonstrate the reliability and validity of the WLQ-J. It is expected that human resource functions such as senior management, personnel affairs, line management, and occupational health staff over a wide range of industries will use the WLQ-J. Further studies are needed to verify the reliability and validity of the WLQ-J by examining differences in the WLQ-J arising from gender, age, industry, and occupation between multiple studies, and by finding relationships between the WLQ-J and other evaluation scales.

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Objectives: In designing a local exhaust ventilation (LEV) system, the exhaust airflow rate which will produce the required control velocity at the capture point must be predicted properly. Conventionally, the airflow requirements for LEV hoods have been calculated using Dalla Valle’s equation. Although Dalla Valle’s equation is a simple and convenient formula for LEV design, it is known that the airflow rate predicted by the equation does not always coincide with actual exhaust airflow rate. In order to develop a new airflow formula which can substitute for Dalla Valle’s equation, the author aimed to develop an empirical airflow formula for a slot type exhaust hood using the least square method. Methods: Based on the actual measurements (exhaust airflow rate, suction velocity, hood size and centerline distance) of test slot type hoods in several configurations and conditions, an empirical approximation formula which predicts exhaust airflow rate was developed. In this study, the approximation formula was described as a polynomial linear expression, and the validity of the predicted exhaust airflow rate by the approximation formula was confirmed by comparing with measured airflow rates. Results: It was found that the predicted airflow rates of the developed approximation formula were in good agreement with the measured airflow rates and were more accurate than the airflow rates predicted by Dalla Valle’s equation. Conclusions: Although the applicability of the developed formula is inferior to that of Dalla Valle’s equation, certain economic benefits can be derived from the developed formula in some cases.

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