Assessment of radio frequency exposures in schools, homes, and public places in Belgium

Characterization of exposure from emerging radio frequency (RF) technologies in areas where children are present is important. Exposure to RF electromagnetic fields (EMF) was assessed in three "sensitive" microenvironments; namely, schools, homes, and public places located in urban environments and compared to exposure in offices. In situ assessment was conducted by performing spatial broadband and accurate narrowband measurements, providing 6-min averaged electric-field strengths. A distinction between internal (transmitters that are located indoors) and external (outdoor sources from broadcasting and telecommunication) sources was made. Ninety-four percent of the broadband measurements were below 1 V m(-1). The average and maximal total electric-field values in schools, homes, and public places were 0.2 and 3.2 V m(-1) (WiFi), 0.1 and 1.1 V m(-1) (telecommunication), and 0.6 and 2.4 V m(-1) (telecommunication), respectively, while for offices, average and maximal exposure were 0.9 and 3.3 V m(-1) (telecommunication), satisfying the ICNIRP reference levels. In the schools considered, the highest maximal and average field values were due to internal signals (WiFi). In the homes, public places, and offices considered, the highestmaximal and average field values originated from telecommunication signals. Lowest exposures were obtained in homes. Internal sources contributed on average more indoors (31.2%) than outdoors (2.3%), while the average contributions of external sources (broadcast and telecommunication sources) were higher outdoors (97.7%) than at indoor positions (68.8%). FM, GSM, and UMTS dominate the total downlink exposure in the outdoor measurements. In indoor measurements, FM, GSM, and WiFi dominate the total exposure. The average contribution of the emerging technology LTE was only 0.6%

Conduct of a personal radiofrequency electromagnetic field measurement study: proposed study protocol

Background: The development of new wireless communication technologies that emit radio frequency electromagnetic fields (RF-EMF) is ongoing, but little is known about the RF-EMF exposure distribution in the general population. Previous attempts to measure personal exposure to RF-EMF have used different measurement protocols and analysis methods making comparisons between exposure situations across different study populations very difficult. As a result, observed differences in exposure levels between study populations may not reflect real exposure differences but may be in part, or wholly due to methodological differences. Methods: The aim of this paper is to develop a study protocol for future personal RF-EMF exposure studies based on experience drawn from previous research. Using the current knowledge base, we propose procedures for the measurement of personal exposure to RF-EMF, data collection, data management and analysis, and methods for the selection and instruction of study participants. Results: We have identified two basic types of personal RF-EMF measurement studies: population surveys and microenvironmental measurements. In the case of a population survey, the unit of observation is the individual and a randomly selected representative sample of the population is needed to obtain reliable results. For microenvironmental measurements, study participants are selected in order to represent typical behaviours in different microenvironments. These two study types require different methods and procedures. Conclusion: Applying our proposed common core procedures in future personal measurement studies will allow direct comparisons of personal RF-EMF exposures in different populations and study areas

Assessment of portable and miniaturized sensors for the monitoring of human exposure to air pollutants

In the last years, several in-field campaigns have been conducted using portable and miniaturized monitors to evaluate the personal exposure to different pollutants. In general, this kind of monitors are characterized by worse metrological performance if compared to the traditional standard methods. Despite this disadvantage, portable and miniaturized monitors could be easily used across different applications, because their advantageous features, such as the capability to provide real-time measurement, the high spatial and temporal resolution of acquired data, the ability to adapt to different experimental designs and, especially, the ability to follow the subject in any activity. Finally, portable and miniaturized instruments can provide data acquired in the respiratory zone of the subject, following therefore the practices for a correct exposure assessment. Obviously, the best compromise between the analytical gold standard (in terms of precision, accuracy and instrumental sensitivity) and the gold standard in regard to the exposure assessment should be chosen. Therefore, in brief, principal aims of this thesis are (i) to evaluate the on-field performances of portable and miniaturized monitors for gaseous pollutants and airborne PM and (ii) to use these monitors in exposure assessment studies and (iii) to understand if data acquired via portable and miniaturized monitors could be useful in other fields of application, such as epidemiological studies or toxicological studies, in which the evaluation of the inhaled dose of pollutants could play a key role

Assessment of portable and miniaturized sensors for the monitoring of human exposure to air pollutants

In the last years, several in-field campaigns have been conducted using portable and miniaturized monitors to evaluate the personal exposure to different pollutants. In general, this kind of monitors are characterized by worse metrological performance if compared to the traditional standard methods. Despite this disadvantage, portable and miniaturized monitors could be easily used across different applications, because their advantageous features, such as the capability to provide real-time measurement, the high spatial and temporal resolution of acquired data, the ability to adapt to different experimental designs and, especially, the ability to follow the subject in any activity. Finally, portable and miniaturized instruments can provide data acquired in the respiratory zone of the subject, following therefore the practices for a correct exposure assessment. Obviously, the best compromise between the analytical gold standard (in terms of precision, accuracy and instrumental sensitivity) and the gold standard in regard to the exposure assessment should be chosen. Therefore, in brief, principal aims of this thesis are (i) to evaluate the on-field performances of portable and miniaturized monitors for gaseous pollutants and airborne PM and (ii) to use these monitors in exposure assessment studies and (iii) to understand if data acquired via portable and miniaturized monitors could be useful in other fields of application, such as epidemiological studies or toxicological studies, in which the evaluation of the inhaled dose of pollutants could play a key role

Effects of radiofrequency electromagnetic field exposure on sleep quality

The use of wireless communication devices, which emit radiofrequency electromagnetic fields (RF-EMF), has increased in the past decades. According to the World Health Organization (WHO) mobile phone use is ubiquitous with an estimated 4.6 billion subscriptions globally. The missing knowledge about a biological mechanism and the attribution of non-specific symptoms of ill health to RF-EMF has led to an increased public concern about possible adverse health effects from this radiation. One of the most often reported symptoms due to RF-EMF exposure are sleep disturbances. In several randomised double-blind human laboratory studies, changes in the sleep electroencephalogram (EEG) after exposure to RF-EMF were observed. The impact of these small changes on sleep quality and therefore on general well-being is unclear. Previous epidemiological studies have used a cross-sectional design, which is not appropriate for establishing causal relationships between exposure and outcome. Studies with a cohort design are therefore needed. Additionally, exposure assessment was mostly inadequate or only parts of the real exposure situation were taken into account. Personal measurement devices (exposimeters) have become available a few years age. In large epidemiological studies, it is very time-consuming and costly to use such devices. Other exposure assessment methods are therefore needed. The main aim of this thesis was to investigate the association between personal RF-EMF exposure and sleep quality by using objective as well as subjective data. To predict personal exposure to RF-EMF a comprehensive exposure assessment method was applied. This thesis was part of the QUALIFEX project (a prospective cohort study on radiofrequency electromagnetic field exposure and health related quality of life) which is embedded in the National Research Program 57 (NRP-57) about non-ionising radiation. The health effect of RF-EMF exposure was investigated in a cohort study which consisted of a baseline survey in May 2008 and a follow-up survey one year later. Questionnaires entitled „Environment and Health“ were sent out to 1375 randomly selected study participants in the region of Basel (Switzerland). Information on sleep quality, on exposure relevant factors and on various confounding factors was collected. By means of a pre-study, which was not part of this thesis, a comprehensive exposure assessment method was developed. To predict personal exposure to far-field RF-EMF (e.g mobile phone base stations or radio transmitters), a validated full exposure prediction model was used which was developed based personal exposure measurements of 166 study participants who took part in a pre-study. Exposure to close to body sources was assessed using self-reported data on mobile phone and cordless phone use. Objective data of mobile phone use from network operators for participants who gave informed consent were additionally collected. For a nested sleep study, 120 participants out of the baseline survey took part in a nested sleep study to verify our previous results. Sleep quality and sleep behavior was assessed using actigraphy and exposure to RF-EMF was measured by means of personal exposimeters. For the baseline survey, mean calculated RF-EMF exposure to all relevant sources of all 1375 study participants was 0.12 mW/m2 (0.21 V/m). Exposure at the follow-up survey was 0.13 mW/m2 (0.22 V/m) and therefore comparable with the baseline exposure. No consistent association between RF-EMF exposure and self-reported sleep quality neither in the baseline analysis (cross-sectional analysis) nor in the cohort analysis (longitudinal analysis) was observed. In the nested sleep study, objective data on exposure and sleep quality did not yield any association between exposure and sleep quality. The QUALIFEX project was the first study which applied a cohort design to investigate the association between RF-EMF exposure and sleep quality. Additionally, we were able to verify our results of the cohort study with objective data obtained in a nested sleep study. Overall, we found no consistent association between self-reported as well as objectively measured sleep quality and exposure to relevant RF-EMF sources in everyday life. Our results increase the evidence for a true absence of an effect of RF-EMF exposure on sleep quality. Our study used a very comprehensive exposure assessment method which included far-field sources as well as close to body sources. In general, exposure levels were very small and changes between the baseline and the follow-up survey were marginal. Hence, with our study no conclusions can be drawn regarding potential health effects of higher exposure levels. In future studies, more data on long-term effects have to be collected. Additionally, the exposure situation in everyday life should be monitored because new technologies operating with RF-EMF are continuously arising

Representativeness and repeatability of microenvironmental personal and head exposures to radio-frequency electromagnetic fields

The aims of this study were to: i) investigate the repeatability and representativeness of personal radio frequency-electromagnetic fields (RF-EMFs) exposure measurements, across different microenvironments, ii) perform simultaneous evaluations of personal RF-EMF exposures for the whole body and the head, iii) validate the data obtained with a head-worn personal distributed exposimeter (PDE) against those obtained with an on-body worn personal exposimeter (PEM). Data on personal and head RF-EMF exposures were collected by performing measurements across 15 microenvironments in Melbourne, Australia. A body-worn PEM and a head-worn PDE were used for measuring body and head exposures, respectively. The summary statistics obtained for total RF-EMF exposure showed a high representativeness (r(2) > 0.66 for two paths in the same area) and a high repeatability over time (r(2) > 0.87 for repetitions of the same path). The median head exposure in the 900 MHz downlink band ranged between 0.06 V/m and 0.31 V/m. The results obtained during simultaneous measurements using the two devices showed high correlations (0.42 < r(2) < 0.94). The highest mean total RF-EMF exposure was measured in Melbourne's central business district (0.89 V/m), whereas the lowest mean total exposure was measured in a suburban residential area (0.05 V/m). This study shows that personal RF-EMF microenvironmental measurements in multiple microenvironments have high representativeness and repeatability over time. The personal RF-EMF exposure levels (i.e. body and head exposures) demonstrated moderate to high correlations

Spatial and temporal variability of personal environmental exposure to radio frequency electromagnetic fields in children in Europe

Exposure to radiofrequency electromagnetic fields (RF-EMF) has rapidly increased and little is known about exposure levels in children. This study describes personal RF-EMF environmental exposure levels from handheld devices and fixed site transmitters in European children, the determinants of this, and the day-to-day and year-to-year repeatability of these exposure levels.; Personal environmental RF-EMF exposure (μW/m; 2; , power flux density) was measured in 529 children (ages 8-18 years) in Denmark, the Netherlands, Slovenia, Switzerland, and Spain using personal portable exposure meters for a period of up to three days between 2014 and 2016, and repeated in a subsample of 28 children one year later. The meters captured 16 frequency bands every 4 s and incorporated a GPS. Activity diaries and questionnaires were used to collect children's location, use of handheld devices, and presence of indoor RF-EMF sources. Six general frequency bands were defined: total, digital enhanced cordless telecommunications (DECT), television and radio antennas (broadcast), mobile phones (uplink), mobile phone base stations (downlink), and Wireless Fidelity (WiFi). We used adjusted mixed effects models with region random effects to estimate associations of handheld device use habits and indoor RF-EMF sources with personal RF-EMF exposure. Day-to-day and year-to-year repeatability of personal RF-EMF exposure were calculated through intraclass correlations (ICC).; Median total personal RF-EMF exposure was 75.5 μW/m; 2; . Downlink was the largest contributor to total exposure (median: 27.2 μW/m; 2; ) followed by broadcast (9.9 μW/m; 2; ). Exposure from uplink (4.7 μW/m; 2; ) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m; 2; ) than night (23.0 μW/m; 2; ), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m; 2; ) or traveling (171.3 μW/m; 2; ), and much lower at home (33.0 μW/m; 2; ) or in school (35.1 μW/m; 2; ). Children living in urban environments had higher exposure than children in rural environments. Older children and users of mobile phones had higher uplink exposure but not total exposure, compared to younger children and those that did not use mobile phones. Day-to-day repeatability was moderate to high for most of the general frequency bands (ICCs between 0.43 and 0.85), as well as for total, broadcast, and downlink for the year-to-year repeatability (ICCs between 0.49 and 0.80) in a small subsample.; The largest contributors to total personal environmental RF-EMF exposure were downlink and broadcast, and these exposures showed high repeatability. Urbanicity was the most important determinant of total exposure and mobile phone use was the most important determinant of uplink exposure. It is important to continue evaluating RF-EMF exposure in children as device use habits, exposure levels, and main contributing sources may change