Journal of School of Public Health and

Background and Aim: Laboratory fume-hoods are the first-level protection for the laboratory staff against hazardous chemical pollutants. Considering the large numbers of personnel, especially in petrochemical industry laboratories, this project was carried out in order to assess the performance of laboratory hoods based on tracer gas (SF6).

Materials and Methods: In this project 22 hoods in the laboratories of a petrochemical industry were studied. Operation of the hoods was assessed based on quantitative (with SF6 as tracer gas) and qualitative (face velocity measurement, using thermal anemometer) tests, according to ASHRAE 110 stndard.

Results: In comparison with the minimum acceptable face velocity (80 fpm), the mean values of face velocities of only 9.09% of the hoods passed the test (P=0.001) and were at an acceptable level. As regards the tracer gas test, the results were even worse: only 4.5% of the hoods passed the acceptability test (p=0.001). In addition, non of the hoods having an acceptable face velocity passed the tracer gas test. Similarly, no hood with an accepatable tracer gas performance had an acceptable face velocity.

Conclusion: Since there is no consistency between face velocity and tracer gas tests, performance of laboratory hoods can necessarily be assessed on the basis of the tracer gas quantitative test. The face velocity test is a supplementary test, which, if used alone wil give false results.

Background and Aim: The present research aimed to study the psychometric characteristics of a subjective well-being questionnaire among high school students.

Materials and Methods: This was a descriptive correlational study. A total of 400 high school students (200 boys and 200 girls) in the City of Ghom, Iran were selected by multistage cluster sampling.  Data were collected using the Oxford subjective well-being and happiness inventory questionnaire. Factor analysis and Cronbach's alpha coefficient and the Pearson correlation test were used to analyze the data. 

Results: Factor analysis showed that the scale was saturated with four factors. In addition, Pearson correlation test indicated that subjective well-being was positively associated (p < 0.01) with happiness (r=0.27), discipline (r=0.11) and academic achievement (r=0.28). Also the reliability of the subjective well-being questionnaire using Cronbach's alpha was found to be  0.87 for the total scale and 0.69, 0.85, 0.73 and 0.78 for the subscales school connectedness, joy of learning, educational purpose and academic efficacy, respectively; these findings indicate that the tool used was quite good and reliable.

Conclusions: Based on the findings is concluded that the Persian version of the subjective well-being questionnaire is an acceptable tool to determine the psychometric characteristics of high school students and can be used as a valid instrument in psychological research.