| 1. |
- Sandström, Monica, 1946-, et al.
(författare)
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A survey of electric and magnetic-fields among VDT operators in offices
- 1993
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Ingår i: IEEE transactions on electromagnetic compatibility (Print). - New York : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9375 .- 1558-187X. ; 35:3, s. 394-397
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the ambient electric and magnetic fields as well as the electromagnetic fields associated with VDT's at 150 offices are measured. The aim of the study is to find out the general level of the various electromagnetic parameters in offices and establish a technical base for a case referent study of skin symptoms among VDT workers. The median value of the 50-Hz background field in the 150 offices is 0.07 muT. Seven of the offices have background levels higher than 0.5 muT, which is high enough to cause distortion of the picture on the screen. The dominating source for electric fields in the ELF range is electric equipment in the office, not the VDT's. The median value of the electric field in the VLF range is 1.5 V/m. The equivalent surface potential is less than 0.5 kV for 63% of the measured VDT's. The computer monitor is a major source for magnetic fields in the offices. The median value of the magnetic field in the ELF range in front of the VDT is 0.21 muT, and in the VLF range 0.03 muT.
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| 2. |
- Sandström, Monica, 1946-, et al.
(författare)
-
Skin symptoms among VDT workers and electromagnetic-fields : a case-referent study
- 1995
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Ingår i: Indoor Air. - : John Wiley & Sons. - 0905-6947 .- 1600-0668. ; 5:1, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Th is case referent study is a part of the Office illness Project in Northern Sweden. From a questionnaire study among 5986 office workers, 75 VDT workers with self-reported facial skin symptoms and the same number of referents were selected for this study. The environmental electric and magnetic fields in the office as well as electromagnetic fields associated with the VDT at the workplace were measured, The aim of this part of the project was to explore the role of the measured electromagnetic parameters in relation to skin symptoms. For most of the measured parameters there was no difference between cases and referents. However, more cases than referents were found in the highest exposure group for two of the measured parameters. Fm the background electric field in the mom the relative risk in terms of crude odds ratio (OR) was 3.0 (95% CI: 1.2-7.2) for the high exposed group (greater than or equal to 31 V/m) compared with the lowest group (less than or equal to 10 V/m). The same comparison for the magnetic field in the ELF-range (greater than or equal to 0.30 mu T vs less than or equal to 0.145 mu T) in front of the VDT gave an OR of 2.7(95% CI: 1.0-6.9).
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| 3. |
- Andersson, N., et al.
(författare)
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Amplitude modulation of light from various sources
- 1994
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Ingår i: Lighting Research and Technology. - : Sage Publications. - 1477-1535 .- 1477-0938. ; 26:3, s. 157-160
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Tidskriftsartikel (refereegranskat)abstract
- This work was done to obtain basic knowledge about various light sources and specially about light modulation, or flicker. The study showed that the modulation of light varied a lot between different ordinary light sources. In general the 100 Hz component in the flickering light dominated. For incandescent lights the modulation increased with decreasing power and was in the range 10-22%. Light from the tungsten-halogen lamps had 2-6% modulation. The most common light sources (single-colour fluorescent light) had a modulation of about 20%. Fluorescent tubes with better colour rendering (full-colour fluorescent and full-colour special fluorescent tubes) had a higher modulation, 30-40%, while light from high-frequency (HF) fluorescent tubes had a modulation of 0.9%. Light from conventional compact fluorescent tubes had a modulation degree of about 44%, and for HF compact fluorescent tubes it was 2-7%. Modulation of light from HF compact fluorescent tubes had a tendency to decrease with increasing tube size. The modulation of light from discharge lamps was in the range of 52% up to 100% and the curve form of the light from low pressure sodium vapour lamp (100% modulation) contained several high frequency components.
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| 4. |
- Hansson Mild, Kjell, 1942-, et al.
(författare)
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ELF noise fields : a review
- 2010
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Ingår i: Electromagnetic Biology and Medicine. - : Informa Healthcare. - 1536-8378 .- 1536-8386. ; 29:3, s. 72-97
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Tidskriftsartikel (refereegranskat)abstract
- The debate as to whether low-level electromagnetic fields can affect biological systems and in the long term cause health effects has been going on for a long time. Yet the interaction of weak electromagnetic fields (EMF) with living cells, undoubtedly a most important phenomenon, is still not well understood. The exact mechanisms by which the effects are produced have not been identified. Furthermore, it is not possible to clearly define which aspects of an EMF exposure that constitute the "dose." One of the groups that contributed to solving this problem is the Bioelectromagnetics group at Catholic University of America (CUA), Washington, D. C. Their work has been devoted to investigating the physical parameters that are needed to obtain an effect of EMF exposure on biological systems, and also how to inhibit the effect. This is a review of their work on bioeffects caused by low-level EMF, their dependence on coherence time, constancy, spatial averaging, and also how the effects can be modified by an applied ELF noise magnetic field. The group has been using early chick embryos, and L929 and Daudi cells as their main experimental systems. The review also covers the work of other groups on low-level effects and the inhibition of the effects with an applied noise field. The group at CUA has shown that biological effects can be found after exposure to low-level ELF and RF electromagnetic fields, and when effects are observed, applying an ELF magnetic noise field inhibits the effects. Also, other research groups have tried to replicate the studies from the CUA group, or to apply EMF noise to suppress EMF-induced effects. Replications of the CUA effects have not always been successful. However, in all cases where the noise field has been applied to prevent an observed effect, it has been successful in eliminating the effect.
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| 5. |
- Hansson Mild, Kjell, 1942-, et al.
(författare)
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Is there any exposure from a mobile phone in stand-by mode?
- 2012
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Ingår i: Electromagnetic Biology and Medicine. - : Informa Healthcare. - 1536-8378 .- 1536-8386. ; 31:1, s. 52-56
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have been using a GSM mobile phone in stand-by mode as the source for exposure, and they claimed that this caused effects on for instance sleep and testicular function. In stand-by mode the phone is only active in periodic location updates, and this occurs with a frequency set by the net operator. Typical updates occur with 2-5 h in between, and between these updates the phone is to be considered as a passive radio receiver with no microwave emission. Thus, the exposure in stand-by mode can be considered negligible.
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| 6. |
- Moen, Bente E., et al.
(författare)
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Accidental exposure to electtromagnetic fields from the radar of a naval ship : a descriptive study
- 2013
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Ingår i: International Maritime Health. - : Via Medica. - 1641-9251 .- 2081-3252. ; 64:4, s. 177-182
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Tidskriftsartikel (refereegranskat)abstract
- Part of a crew on a Norwegian naval ship was exposed to the radar waves for approximately 7 min from an American destroyer during an incident at sea in August 2012. Information about the exposure was not given by the navy. This is a description of what happened with the crew on board after this event. 14 persons had been on the ship bridge or outside on the deck during the exposure and the rest of the crew had been inside the ship. 27 persons were examined at a hospital 6–8 months after the event, as they had developed a large number of symptoms from different organ systems. They were very worried about all types of possible adverse health effects due to the incident. All were examined by an occupational physician and an ophthalmologist, by an interview, clinical examinations and blood tests at the hospital. The interview of the personnel revealed that they had not experienced any major heating during the episode. Their symptoms developed days or weeks after the radar exposure. They had no objective signs of adverse health effects at the examination related to the incident. Long-term health effect from the exposure is highly unlikely. The development of different symptoms after the incident was probably due to the fear of possible health consequences. Better routines for such incidents at sea should be developed to avoid this type of anxiety.
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| 7. |
- Sandström, Monica, 1946-, et al.
(författare)
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External power frequency magnetic field-induced jitter on computer monitors
- 1993
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Ingår i: Behaviour & Information Technology. - : Taylor & Francis. - 0144-929X .- 1362-3001. ; 12:6, s. 359-363
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Tidskriftsartikel (refereegranskat)abstract
- Power frequency magnetic fields with flux densities greater than 0.5 μT are not uncommon in offices. This level has been shown to induce jitter on VDT monitors. In the present project, these magnetic field-induced disturbances have been studied in the laboratory in order to establish a firm technical basis for future studies of the disturbance's influence on eye strain in VDT workers. Eight volunteers judged the occurrence of distortion when an applied external magnetic field was varied both in amplitude and frequency for 8 investigated VDT screens. The level of the external 50 Hz magnetic field when the distortion was detectable ranged from 0.6 to 1.1 μT. If the screen was viewed through a stereomicroscope (25 × magnification), the corresponding level was in the order of 0.2 μT. If the frequency difference between the external magnetic field and the refresh rate of the screen is only ±1-2 Hz, the disturbance is noticeable at even lower flux densities.
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| 8. |
- Sandström, Monica, 1946-, et al.
(författare)
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Neurophysiological effects of flickering light in patients with perceived electrical hypersensitivity
- 1997
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Ingår i: Journal of Occupational and Environmental Medicine. - : Wolters Kluwer. - 1076-2752 .- 1536-5948. ; 39:1, s. 15-22
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Tidskriftsartikel (refereegranskat)abstract
- An increasing number of people in Sweden are claiming that they are hypersensitive to electricity, These patients suffer from shin as well as neurological symptoms when they are near computer monitors, fluorescent tubes, or other electrical appliances, Provocation studies with electromagnetic fields emitted from these appliances have, with only one exception, all been negative, indicating that there are other factors in the office environment that can effect the autonomic and/or central nervous system resulting in the symptoms reported, Flickering light is one such factor and was therefore chosen as the exposure parameter in this study, Ten patients complaining of electrical hypersensitivity and the same number of healthy voluntary control subjects were exposed to amplitude-modulated light, The sensitivity of the brain to this type of visual stimulation was tested by means of objective electrophysiological methods such as electroretinography and visual evoked potential, A higher amplitude of brain cortical responses at all frequencies of stimulation was found when comparing patients with the control subjects, whereas no differences in retinal responses were revealed.
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| 9. |
- Sandström, Monica, 1946-, et al.
(författare)
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Power frequency magnetic fields and computer monitor instability
- 1998
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Ingår i: Displays (Guildford). - : Elsevier. - 0141-9382 .- 1872-7387. ; 19:2, s. 85-90
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Tidskriftsartikel (refereegranskat)abstract
- Owing to the increased use of electronic loads, the harmonic content of the magnetic field in buildings has increased and it is therefore of interest to study how the harmonics (i.e. 150 Hz magnetic fields) will affect the stability of the picture on the monitor screen. Another frequency of interest to study is 16.7 Hz, the frequency used by the Swedish railway. Ten volunteers were asked to judge the occurrence of jitter on a 15-in. color monitor screen, refresh rate 72.2 Hz, at different amplitudes and frequencies of the vertical applied magnetic field. The tested screen had a highest sensitivity to 150 Hz external magnetic field, followed by 60, 16.7 and 50 Hz. In a static magnetic field the screen had a sensitivity (displacement) of 0.031±0.006 mm per applied microtesla.
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| 10. |
- Söderqvist, Fredrik, et al.
(författare)
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Childhood brain tumour risk and its association with wireless phones : a commentary
- 2011
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Ingår i: Environmental Health. - : BioMed Central (BMC). - 1476-069X. ; 10:1, s. 106-119
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Tidskriftsartikel (refereegranskat)abstract
- Case-control studies on adults point to an increased risk of brain tumours (glioma and acoustic neuroma) associated with the long-term use of mobile phones. Recently, the first study on mobile phone use and the risk of brain tumours in children and adolescents, CEFALO, was published. It has been claimed that this relatively small study yielded reassuring results of no increased risk. We do not agree. We consider that the data contain several indications of increased risk, despite low exposure, short latency period, and limitations in the study design, analyses and interpretation. The information certainly cannot be used as reassuring evidence against an association, for reasons that we discuss in this commentary.
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