Safety Evaluation of the Lighting at the Entrance of a Very Long Road Tunnel: A Case Study in Ilam

BACKGROUND: At the entrance of a tunnel, reflection of sunlight from the surrounding environment and a lack of adequate lighting usually cause some vision problems. The purpose of this study was to perform a safety evaluation of lighting on a very long road in Ilam, Iran. METHODS: The average luminance was measured using a luminance meter (model S3; Hagner, Solna, Sweden). A camera (model 108, 35-mm single-lens reflex; Yashica, Nagano, Japan) was used to take photographs of the safe stopping distance from the tunnel entrance. Equivalent luminance was determined according to the Holliday polar diagram. RESULTS: Considering the average luminance at the tunnel entrance (116.7 cd/m²) and using Adrian's equation, the safe level of lighting at the entrance of the tunnel was determined to be 0.7. CONCLUSION: A comparison between the results of the safe levels of lighting at the entrance of the tunnel and the De Boer scale showed that the phenomenon of black holes is created at the tunnel entrance. This may lead to a misadaptation of the drivers’ eyes to the change in luminance level at the entrance of the tunnel, thereby increasing the risk of road accidents in this zone.

[Evaluation of extremely low frequency [ELF] electromagnetic fields and their probable relationship with hematological changes among operators in heavy metal industry]

It is important that biological and health effects from the induction of currents and fields in the body by extremely low frequency [ELF] fields are fully explored to determine the effects produced at the molecular, cellular and organ levels. The objective of this study was to evaluate the intensity of ELF electromagnetic fields and its probable relationship with hematological changes among operators in a heavy metal industry site. This is a case study. In the present study, 205 workers exposed to electromagnetic fields [EMF] were working in four categories:[1] induction furnace workers, [2] induction hardening workers, [3] welders, [4] computer operators. A variety of methods for exposure assessment have been devised and applied to epidemiological studies of the effects of EMF in occupational settings. The methods range from rather crude job-classification methods, to sophisticated job-exposure matrix [JEM] modeling based on personal exposure measurements and reconstruction of past exposure. Monitoring procedures were carried out to measure the levels of exposure to ELF electric and magnetic fields. The strength of the electric and magnetic fields was measured by a dosimetric method [NIOSH 203]. Workers' blood samples were collected and analyzed for identifying different blood parameters. The results of hematological changes of workers in their medical files were also used for evaluation. Measurements showed a high strength of ELF filed at the induction furnace workplace. Total electric field ranged from 2.3 to 2452.3 V/M and magnetic field from 1 to 325.1 micro T. In other workshops including induction hardening, total electric field ranged from 2.45 to 68.5 V/M, magnetic field from 1.3 to 20.4 micro T, total electric filed from 1.02 to 11.23 V/M, magnetic field from 0.12 to 3.25 micro T in the welding department and finally for computer operators this range was 20.1 to 186.2 V/m for electric field and 0.07 to 0.25 mirco T for magnetic field. Mean value of WBC and MCV increased significantly among exposed induction furnace workders group [P<0.05], but RBC decreased. Mean value of WBC, MCHC and MCV increased significant among the exposed induction hardening workers group [P<0.05], but RBC and Hgb decreased. Mean value of WBC, MCV and Hgb increased significantly among the exposed welders group [P<0.05], but Hgb in relation with age decreased. Mean value of RVc and MCH decreased significantly among exposed computer operators group / [P<0.05]