Leena Korpinen

Self-report of physical symptoms associated with using mobile phones and other electrical devices.

The aim of our work was to study the working-age populations self-reported physical symptoms associated with using mobile phones and other electrical devices. A qualitative method was applied using an open-ended question in a questionnaire, which included questions about the possible influence of new technical equipment on health. We then created subgroups of respondents for different self-reported symptoms associated with mobile phones and other electrical devices. The research questions were: (1) how the respondents described physical symptoms associated with using mobile phones and other electrical devices and (2) how the answers can be classified into subgroups based on symptoms or devices. We identified the following categories: (1) respondents with different self-reported symptoms which they associated with using mobile phones (headache, earache, or warmth sensations), (2) respondents who had skin symptoms when they stayed in front of a computer screen, (3) respondents who mentioned physical symptoms associated with using mobile phones and other electrical devices. Total prevalence of self-reported physical symptoms associated with using mobile phones and other electrical devices (categories 1 and 2) was 0.7%. In the future it will be possible to obtain new knowledge of these topics by using qualitative methods.

Evaluation of current densities and total contact currents in occupational exposure at 400 kV substations and power lines.

This investigation studied the current densities in the neck and total contact currents in occupational exposure at 400 kV substations and power lines. Eight voluntary workers simulated their normal work tasks using the helmet-mask measuring system. In all, 151 work tasks with induced current measurements were made. Work situations were: tasks in 400 kV substations, tasks in 400-110 kV towers and the cutting of vegetation under 400 kV power lines. The average current density in the neck was estimated from the current induced in the helmet. The calculated maximum average current densities in the neck varied from 1.5 to 6.4 mA/m(2) and the maximum total contact currents from 66.8 to 458.4 microA. The study shows that the maximum average current densities and the total contact currents (caused by electric field) in occupational exposure at 400 kV substations and power lines does not exceed the limit and action values (10 mA/m(2) and 1 mA) of the new EU-directive 2004/40/EC (live-line bare-hand works excluded).

Upper limb musculoskeletal disorders in healthcare personnel

The literature on upper limb musculoskeletal disorders (UL-MSD) in different groups of healthcare workers was reviewed: 65 relevant studies were collected. In dentists, the neck was the most frequently affected segment, with prevalences up to 73% and exceeding 50% in 7 out of 12 studies. In dental hygienists and in laboratory technicians, the hand/wrist had the highest prevalence in the majority of the studies. In nurses, the most seriously affected anatomic sites were the neck and shoulders. Physiotherapists had the lowest prevalence of UL-MSD. A high prevalence of upper limb disease, mainly carpal tunnel syndrome, was reported in dentists, dental hygienists, anesthesia nurses and endoscopists. The high prevalence of upper limb disorders/diseases reported in health personnel supports the hypothesis of a significant risk in these workers. However, the possible role of biomechanical overload, as much as that of stress or other personal factors, cannot be currently assessed. Practitioner Summary: Published studies support the hypothesis of a significant risk of upper limb musculoskeletal disorders in healthcare activities. The neck was the most frequently affected segment in dentists, the hand/wrist in dental hygienists and in laboratory technicians, and the neck and shoulders in nurses. Lower prevalence was reported in physiotherapists. A high prevalence of carpal tunnel syndrome was also observed in various healthcare activities.

Mental Symptoms and the Use of New Technical Equipment

The aim of this paper was to present how mental symptoms are connected to the use of desktop, portable or minicomputers (communicators and hand-held computers), mobile phones, and background information such as age and gender in the Finnish working-age population. The study was carried out as a cross-sectional study by posting a questionnaire to 15 000 working-age (18-65) Finns. The mental symptoms of 6121 respondents were analysed using the model factors age, gender, the use of computers and the use of mobile phones. In all data, the use of desktop computers was related to mental symptoms. However, the results of our data are not highly reliable, because the nonresponse rate was over 50%. Nevertheless, it may be essential to take into account in the future that working with computers can increase workers’ mental symptoms, and it is important to observe their mental health.

Measuring occupational exposure to electric and magnetic fields at 400 kV substations

The new European Union directive states that if the electric and magnetic field action values of 10 kV/m or 500 muT at the working place are exceeded, the employer has to ensure that the limit value, given as an induced current density in the body, is not exceeded. The aim of this study was to measure field strengths and find out how the new directive will affect working at Finnish 50 Hz, 400 kV substations. Spots where the action value was exceeded could be found at 75 % of the selected eight substations. The largest electric field strength, 14.3 kV/m, was measured between two adjacent busbars carrying the voltages having the same phase angle. Over 500 muT magnetic flux density was measured in one substation at the safety fence around a three-phase air-core reactor set. Fields were measured at a height 1 m above the ground. According to simple ellipsoid calculations the exposure limit, 10 mA/m of induced current density in the head or trunk, will not be exceeded. However, many of the maintenance tasks have to be done closer to the conductors and busbars and thus more in-depth study and measurements will be necessary at least in Finland.

Numerical evaluation of currents induced in a worker by ELF non‐uniform electric fields in high voltage substations and comparison with experimental results

An ungrounded human, such as a substation worker, receives contact currents when touching a grounded object in electric fields. In this article, contact currents and internal electric fields induced in the human when exposed to non-uniform electric fields at 50 Hz are numerically calculated. This is done using a realistic human model standing at a distance of 0.1-0.5 m from the grounded conductive object. We found that the relationship between the external electric field strength and the contact current obtained by calculation is in good agreement with previous measurements. Calculated results show that the contact currents largely depend on the distance, and that the induced electric fields in the tissues are proportional to the contact current regardless of the non-uniformity of the external electric field. Therefore, it is concluded that the contact current, rather than the spatial average of the external electric field, is more suitable for evaluating electric field dosimetry of tissues. The maximum induced electric field appears in the spinal cord in the central nervous system tissues, with the induced electric field in the spinal cord approaching the basic restriction (100 mV/m) of the new 2010 International Commission on Non-Ionizing Radiation Protection guidelines for occupational exposure, if the contact current is 0.5 mA.

Occupational exposure to electric fields and currents associated with 110 kv substation tasks

The main aim of this study was to investigate occupational exposure to electric fields, and current densities and contact currents associated with tasks at air-insulated 110 kV substations and analyze if the action value of EU Directive 2004/40/EC was exceeded. Four workers volunteered to simulate the following tasks: Task (A) maintenance of an operating device of a disconnector at ground or floor level, Task (B) maintenance of an operating device of a circuit breaker at ground or floor level, Task (C) breaker head maintenance from a man hoist, and Task (D) maintenance of an operating device of a circuit breaker from a service platform. The highest maximum average current density in the neck was 1.8 mA/m(2) (calculated internal electric field 9.0-18.0 mV/m) and the highest contact current was 79.4 µA. All measured values at substations were lower than the limit value (10 mA/m(2)) of the EU Directive 2004/40/EC and the 2010 basic restrictions (0.1 and 0.8 V/m for central nervous system tissues of the head, and all tissues of the head and body, respectively) of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).

Accidents and close call situations connected to the use of mobile phones

The aim of our work was to study the accidents and close call situations connected to the use of mobile phones. We have analyzed how the accidents/close call situations are connected to background information, in particular age, gender and self-reported symptoms. The study was carried out as a cross-sectional study by posting the questionnaire to 15,000 working-age Finns. The responses (6121) were analyzed using the logistic regression models. Altogether 13.7% of respondents had close call situations and 2.4% had accidents at leisure, in which the mobile phone had a partial effect, and at work the amounts were 4.5% and 0.4% respectively, during the last 12 months. Essentially, we found that: (1) men tend to have more close calls and accidents while on a mobile phone, (2) younger people tend to have more accidents and close calls while on a mobile phone, but it does not appear to be large enough to warrant intervention, (3) employed people tend to have more problems with mobile phone usage and accidents/close calls, and (4) there was a slight increase in mobile-phone-related accidents/close calls if the respondent also reported sleep disturbances and minor aches and pains. In the future, it is important to take into account and study how symptoms can increase the risk of accidents or close call situations in which a mobile phone has a partial effect.

Physical Symptoms in Young Adults and Their Use of Different Computers and Mobile Phones

This paper presents the use of new technical equipment by young adults (30 years old or younger), and the physical symptoms they have. The paper then analyses how the symptoms are associated with the use of computers and mobile phones, taking into account the background information. The study is based on a survey of 15000 working-age ( 18-65) Finns. The responses (1563) covering young adults’ physical symptoms were analysed. Altogether 53.3% of all young adults had pretty often or more frequently pain, numbness or aches in the neck and 32.2% had aches in the hip and lower back. Women experienced more pain, numbness or aches in the neck (65.0%) than men (34.5%). The use of different computers at leisure quite often had an association with some symptoms in different parts of the body. In addition, exhaustion at work had associations with some physical symptoms. In the future, it is essential to note ergonomic reasons and exhaustion at work when young adults experience pain, numbness or aches.

Comparison of electric and magnetic fields near 400 kV electric substation with exposure recommendations of the European Union

Measurements of electric and magnetic fields in 400 kV electric power systems have increased because of public concern about fields. Electric and magnetic fields from electric power systems have been studied for several years now at Tampere University of Technology (TUT). The aim of this study was to investigate electric and magnetic fields near a 400 kV substation from the public exposure point of view. Recommendations given by the Council of the European Union for 50 Hz are 5 kV/m for electric field and 100 /spl mu/T for magnetic field. Fields have been measured near 400 kV electric substation along two straight lines, line 1 on the road away from the fence of the substation (n=21, highest values 0.80 kV/m and 1.74 /spl mu/T) and line 2 on the switchyard of the substation (n=83, highest values 7.64 kV/m and 16.5 /spl mu/T). Measurements inside the fence were carried out to get reference values for the fields outside. The values were well below recommendations.