Personal Exposure Meters Research Articles

Revising normative standards for personal noise dosimeters

Personal noise dosimeters are designed to monitor noisy environments and are usually intended to attached to an individual person in order to estimate their exposure to noise over a given period of time. These devices are often used to indicate sound exposure as a percentage of a predetermined criterion. However, different jurisdictions employ different definitions of such quantities and different criteria for permissible exposure. Therefore, existing normative standards for measurement instruments differ in their specifications. For example, while the ASA/ANSI S1.25 standard Specification for Personal Noise Dosimeters makes provisions for use of three level-time exchange rates (3, 4, and 5 dB per doubling of exposure time), the international standard for personal sound exposure meters (IEC 61252) permits only an exchange rate of 3 dB. The International Electrotechnical Commission is revising IEC 61252 to modernize and harmonize requirements for the instruments to reflect the actual practice of measurements of noise exposure worldwide. The technical aims of the revision are to provide realistic specifications, consistent methods for testing all relevant characteristics of a model of instrument, and affordable methods for periodic testing of individual instruments. Potential consequences of the likely changes to IEC 61252 are presented and discussed.

Towards a revised international standard for personal sound exposure meters

Personal sound exposure meters and personal noise dosimeters are designed to be worn on a person and to measure sound exposure or sound exposure as a percentage of a predetermined criterion. Different jurisdictions employ different definitions of these quantities and different criteria for exposure. Existing normative standards for these instruments therefore differ in their specifications and are outdated due to changes in markets and technologies since their publication. The International Electrotechnical Commission is revising the applicable international standard (IEC 61252) to modernise and harmonise requirements for the instruments. The technical aims of the revision are to provide realistic specifications, methods for testing all relevant characteristics of a model of personal sound exposure meter, and methods for periodic testing of individual instruments. Specifications need to reflect the actual practice of measurements of noise exposure worldwide and test methods need to be consistent, realistic, and affordable. The needs of various users have been surveyed and used to prepare substantial technical changes to the specifications in the document. Experience with the equivalent international standard for sound level meters (IEC 61672) has been reviewed to draft new test methods that are appropriate for personal sound exposure meters.

Large-area mobile measurement of outdoor exposure to radio frequencies

A rapid outdoor sampling technique was tested to measure human exposure to radio frequencies in a city of 96,000 inhabitants. The technique consisted of taking measurements with a personal exposure meter inside a moving vehicle. Tests were carried out to quantify the alteration produced by the vehicle's structure and obtain correction factors in order to minimize this alteration. Data were collected at 3065 points where signals in the FM radio and mobile phone wavebands were detected. The coefficients of exposure to sources with multiple frequencies due to thermal effects were calculated from the measured values of the electric field. Kriging was used to generate maps of these coefficients, and these maps were then merged with aerial photographs of the city to readily identify the areas with greater or lesser exposure. The results indicated that the vehicle increased the FM broadcasting radiation readings by a factor of 1.66, but attenuated those of mobile telephony by factors of 0.54–0.66. The mean electric field levels detected throughout the city were 0.231, 0.057, 0.140, 0.124, and 0.110 V/m for the frequency bands FM, LTE 800 (DL), GSM + UMTS 900(DL), GSM 1800(DL), and UMTS 2100(DL), respectively. The mean coefficient of exposure to sources with multiple frequencies was 2.05 × 10−4, and the maximum was 9.81 × 10−3. It can be concluded from the study that it is possible to assess radio frequency exposure using this method, and that the technique is scalable to different sized cities. It also allows measurement at different times so as to analyse the temporal variation of radio frequency levels.

AFRIMETS.AUV.A-S2 final report, calibration of a multi-function acoustic calibrator

Main textResults of Regional Metrology Organisation supplementary comparison AFRIMETS.AUV.A-S2 concerning the calibration of a Brüel & Kjær 4226 multi-frequency sound calibrator are reported here. Sound pressure level results at frequencies from 31.5 Hz to 16 kHz and nominal sound level settings of 94 dB and 114 dB, were evaluated for consistency, the calculated comparison reference values and Degrees of Equivalence are reported here. The comparison's purpose was to prove technical capabilities supporting the submissions of calibration measurement capabilities in the BIPM key comparison database. The light shines quite far, the new calibration measurement capabilities that may result from this work underpin some important fundamental acoustic calibration services, e.g., sound calibrators, sound level meters and personal sound exposure meters. These instruments are intrinsic to the effective monitoring and implementation worldwide of human hearing conservation and hearing loss assessment programs, all of which impacts quality of life. According to the World Health Organization, nearly 1.5 billion people experience some decline in their hearing capacity during their lives [1].To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Measurement of personal radio frequency exposure in Japan: The Hokkaido Study on the Environment and Children's health

The opportunities for exposure to radiofrequency electromagnetic fields (RF-EMF) among children are increasing. Children's exposure to RF-EMF in Japan was recorded using a personal exposure meter (ExpoM-RF), and factors associated with the exposure examined. A total of 101 children, aged 10–15 years old, participated in the prospective birth cohort “Hokkaido study”. RF-EMF data were recorded in the 700 MHz-5.8 GHz frequency range for 3 days. The recorded data were summarized into six groups of frequency bands: downlink from mobile phone base stations (DL), uplink from mobile phones to a base station (UL), Wireless Local Area Network (LAN), terrestrial digital TV broadcasting (digital TV), 2.5 GHz and 3.5 GHz Time Division Duplex (TDD), 1.9 GHz TDD, and total (the summation of power density in all measured frequency bands). A questionnaire was used to document the internet environment (at home) and mobile phone usage. Personal RF-EMF exposure in Japanese children was lower than that reported in studies in Europe. The DL signals from mobile phone base stations were the most significant contributors to total exposure, while Wireless LAN and digital TV were only higher at home. The urban residence was consistently associated with increases in the four groups of frequency bands (DL, UL, digital TV, and TDD). TDD level has several associations with mobile phone usage (calls using mobile phones, video viewing, text message service, and online game). The association between inattention/hyperactivity subscale of the Strengths and Difficulties Questionnaire (SDQ) and higher Wireless LAN exposure at nighttime was also noted. Further studies with additional data will shed light on factors involved in RF-EMF exposure among Japanese children.

Radiofrequency exposure of people living near mobile-phone base stations in France

In response to the demand from a growing number of people concerned about the possible impact of RF-EMF on health, the French National Frequency Agency (ANFR) has published a standardized protocol for in-situ measurements of radiofrequency electromagnetic fields (RF-EMF). This protocol was based on the search for the point of highest field strength and the use of spot measurement.In the framework of an epidemiological study, such spot measurements were implemented in the homes of 354 participants located in urban areas within 250 m of a mobile-phone base station (MPBS) and in the main beam direction of the antenna. Among the participants, more than half accepted to be enrolled in a longer-term study, among whom 152 were equipped with a personal exposure meter (PEM) for 48 h and 40 for seven continuous days. Both spot and PEM measurements quantified downlink field strengths, i.e. FM, TV3-4-5, TETRA I-II-III, 2 GHz–5GHz Wi-Fi, WiMax, GSM900, GSM1800, UMTS900, UMTS 2100, LTE800, LTE1800, and LTE2600.Spot measurements showed a mean/median field strength of 0.58/0.44 V/m for total RF-EMF and 0.43/0.27 V/m from the MPBS. RF-EMF from the MPBS was the dominant source of exposure in 64% of households. Exposure to RF-EMF was influenced by the position of the windows with respect to the MPBS, in particular line-of-site visibility, the distance of the antenna and the floor of the apartment. The PEM surveys showed the measured exposure to be higher during outings than at home and during the day than at night, but there was no difference between the weekends and working days. There was a strong correlation between exposure quantified by both spot and PEM measurements, although spot measures were approximately three times higher than those by PEMs.This study is the first to assess exposure to RF-EMF of people living near a MPBS in urban areas in France. These preliminary results suggest the value of using spot measurements to estimate the impact of the evolution of the mobile-phone network and technology on the exposure of populations to RF-EMF. The low levels of RF-RMF expressed as mean values do not necessarily rule out possible health effects of this exposure.

Dimensionless coefficients for assessing human exposure to radio-frequency electromagnetic fields indoors and outdoors in urban areas

The main objective of this work was to evaluate human exposure to electromagnetic fields in a city of about one hundred thousand inhabitants, both inside and outside dwellings, using exposure quotients. To this end, a personal exposure meter was used, collecting data in different frequency bands, including radio and television broadcasting, mobile telephony, cordless telephones, and wireless communication networks. The indoor measurements were made with the exposure meter in a static position. Those outdoor were made by walking around the building with the exposure meter held by the operator. The median electric field was 0.200 V/m outdoors and 0.102 V/m indoors. The median of the ICNIRP exposure quotients for multiple-frequency sources was 25 10−6 outside and 16 10−6 inside. The proximity of the operator's body caused the readings of the electric field in the FM band to be overestimated by a factor of 1.35, and in the mobile telephony bands by factors from 0.76 to 1.02. The standard deviation of the measurements repeated inside a dwelling over five days was of the order of the exposure meter's standard uncertainty of calibration, but the spatial dispersion at the scale of a dwelling and of the city was much greater. The two main contributors to the exposure were FM radio followed by the “downlink” mobile telephony bands. Inside the dwellings, the DECT and WIFI bands contributed less. Exposure quotients are dimensionless parameters that characterize exposure, and reflect the relative weight of each service to that exposure.

A Multi-Band Body-Worn Distributed Exposure Meter for Personal Radio-Frequency Dosimetry in Diffuse Indoor Environments

A multi-band body-worn distributed exposure meter (BWDM) is designed and calibrated for diffuse fields in a reverberation chamber (RC) for personal exposure assessment in indoor environments. The BWDM uses 22 nodes distributed over the torso and measures the incident power density ( $S_{\mathrm{ inc}}$ ) on body for 11 telecommunication bands in the frequency range of 790–5513 MHz. In order to calibrate the measurement device in diffuse fields, a protocol is proposed for on-body calibration of the BWDM. This protocol is applicable to wearable personal exposure meters in general. The BWDM and the proposed calibration protocol are validated in five indoor locations and five frequency bands (the downlink bands at 800, 900, 1800, and 2100 MHz as well as Wi-Fi 2 GHz) using a tri-axial broadband antenna and a spectrum analyzer (SA). The calibration shows that the BWDM has a relatively low measurement uncertainty with a 68% confidence interval on its antenna apertures, in the range 3.4–5.5 dB. A maximum difference of 0.9 dB is obtained for the total exposure in the test areas between the measurements of the BWDM and SA, which is an excellent agreement.

Personal Exposure to Radiofrequency Electromagnetic Fields Among Palestinian Adults.

This work deals with the assessment of personal exposure to radiofrequency electromagnetic fields and the study of temporal and spatial daily variations in a group of 24 adults from the West Bank, Palestine. Exposure was measured using a personal exposure meter EME SPY 140. Mean values of exposure levels from different radiofrequency sources were calculated using both naive and robust regression on order statistics approaches. The total daily exposure from all radiofrequency electromagnetic field sources varied widely among participants depending on their location, the mobile network they use, their activities, and their mode of transportation, ranging from about 0.2 V m to 0.9 V m. The average total daily exposure of all participants was about 0.48 V m. The main contribution to the mean exposure was from WiFi 2G (45%), GSM900 uplink (19%), GSM900 downlink, and FM radiobroadcasting (each by 11%). Other sources including GSM1800, UMTS2100, WiFi 5G, DECT, TETRA, WiMAX, and TV bands all together contributed 14%. During different activities, participants were exposed to the highest exposure level while traveling and to the lowest exposure while they were sleeping. During the day, participants received the highest exposure during the time period from 1600 to 2400 h. Based on thermal effect of radiofrequency electromagnetic fields, all evaluated personal exposures comply with guidelines recommended for the general public by the International Commission on Non-Ionizing Radiation Protection.

Design and Calibration of a mm-Wave Personal Exposure Meter for 5G Exposure Assessment in Indoor Diffuse Environments

For the first time, a mm-wave personal exposure meter (mm-PEM) for the 5th generation of mobile networks (5G) exposure assessment in indoor diffuse fields is presented. The design is based on simulations and on-phantom calibration measurements in a mm-wave reverberation chamber (RC) at 60 GHz. The mm-PEM consists of an array of nine antennas on the body. Using the mm-PEM, the incident power density (IPD) is measured in the unloaded RC, for the antenna(s) on the phantom and RC loaded with phantom. The uncertainty of the mm-PEM is then determined in terms of its response, which is defined as the ratio of antenna aperture for the above measurement scenarios. Using nine antennas, the designed meter has a response of 1.043 (0.17 dB) at 60 GHz, which is very close to 1 (0 dB), the desired ideal response value. The mm-PEM measured an IPD of 96.6 W m− 2 at 60 GHz in the RC, for an input power of 1 W. In addition, the average absorption cross-section of the phantom is determined as 225 cm2, which is an excellent agreement with its physical dimensions.

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

BackgroundExposure 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. MethodsPersonal environmental RF-EMF exposure (μW/m2, 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). ResultsMedian total personal RF-EMF exposure was 75.5 μW/m2. Downlink was the largest contributor to total exposure (median: 27.2 μW/m2) followed by broadcast (9.9 μW/m2). Exposure from uplink (4.7 μW/m2) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m2) than night (23.0 μW/m2), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m2) or traveling (171.3 μW/m2), and much lower at home (33.0 μW/m2) or in school (35.1 μW/m2). 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. ConclusionThe 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.

Comparative analysis of personal exposure levels induced by long‐term evolution 1800 Re‐farming and other RF sources in an urban environment

Narrowband analysis of real-life up-link (UL) and down-link (DL) trends in personal exposure to recently installed long-term evolution 1800 and other radio frequency sources in typical everyday environments is presented in this work. Results are derived by analysis and post-processing of experimental dataset consisting of 1,677,600 measurement samples, taken at a sampling frequency of 0.25 Hz. The electric field measurements were collected with calibrated personal exposure meters at 90 urban spots, including outdoor and indoor microenvironments. A robust regression from order statistics was applied, enabling the determination of more reliable mean exposure values (V/m) for each wireless and broadcast technology and microenvironment. The exposure ratio for global system for mobile communications (GSM) + long-term evolution (LTE) 1800 (UL) and GSM + LTE 1800 (down link, DL) varied between 0.004 and 0.546% in outdoor environments. The maximal electric field value for the GSM + LTE 900 (DL) was 1.77 V/m, while for GSM + LTE 1800 (DL) this value was 0.644 V/m. The cumulative distribution function of the total radio frequency exposure for the various microenvironments is presented. The research results confirm that exposure levels in an urban environment even after the LTE 1800 Re-farming deployment are far below the International Commission on Non-ionising Radiation Protection reference levels.

A Multi-Band Body-Worn Distributed Radio-Frequency Exposure Meter: Design, On-Body Calibration and Study of Body Morphology

A multi-band Body-Worn Distributed exposure Meter (BWDM) calibrated for simultaneous measurement of the incident power density in 11 telecommunication frequency bands, is proposed. The BDWM consists of 22 textile antennas integrated in a garment and is calibrated on six human subjects in an anechoic chamber to assess its measurement uncertainty in terms of 68% confidence interval of the on-body antenna aperture. It is shown that by using multiple antennas in each frequency band, the uncertainty of the BWDM is 22 dB improved with respect to single nodes on the front and back of the torso and variations are decreased to maximum 8.8 dB. Moreover, deploying single antennas for different body morphologies results in a variation up to 9.3 dB, which is reduced to 3.6 dB using multiple antennas for six subjects with various body mass index values. The designed BWDM, has an improved uncertainty of up to 9.6 dB in comparison to commercially available personal exposure meters calibrated on body. As an application, an average incident power density in the range of 26.7–90.8 μW·m is measured in Ghent, Belgium. The measurements show that commercial personal exposure meters underestimate the actual exposure by a factor of up to 20.6.

Hybrid model for the personal exposure meter response in an outdoor environment.

When a personal exposure meter (PEM) is worn by a human subject, the electric-field strength measured at the PEM is affected by a body shadowing effect. In our study, a hybrid model is proposed for modeling the body shadowing effect for when the PEM is used in an outdoor environment. The hybrid model contains responses to direct and diffused waves, the factors related to the transmission path and cross-polarization discrimination, respectively. To derive the hybrid model, responses for the direct and diffused waves are measured using a human phantom in an anechoic chamber and a reverberation chamber, respectively. Responses are measured at multiple locations in an outdoor environment and compared to the responses of the hybrid model. The hybrid model response has quartiles that deviate by an average of only 2.2 dB (1.29) from the same quartiles of the outdoor responses. Such quartile deviations are significantly smaller than those of the previous model with a body shadowing effect. Bioelectromagnetics. 38:626-647, 2017. © 2017 Wiley Periodicals, Inc.

Neurodevelopment for the first three years following prenatal mobile phone use, radio frequency radiation and lead exposure

BackgroundStudies examining prenatal exposure to mobile phone use and its effect on child neurodevelopment show different results, according to child's developmental stages. ObjectivesTo examine neurodevelopment in children up to 36 months of age, following prenatal mobile phone use and radiofrequency radiation (RFR) exposure, in relation to prenatal lead exposure. MethodsWe analyzed 1198 mother-child pairs from a prospective cohort study (the Mothers and Children's Environmental Health Study). Questionnaires were provided to pregnant women at ≤20 weeks of gestation to assess mobile phone call frequency and duration. A personal exposure meter (PEM) was used to measure RFR exposure for 24h in 210 pregnant women. Maternal blood lead level (BLL) was measured during pregnancy. Child neurodevelopment was assessed using the Korean version of the Bayley Scales of Infant Development-Revised at 6, 12, 24, and 36 months of age. Logistic regression analysis applied to groups classified by trajectory analysis showing neurodevelopmental patterns over time. ResultsThe psychomotor development index (PDI) and the mental development index (MDI) at 6, 12, 24, and 36 months of age were not significantly associated with maternal mobile phone use during pregnancy. However, among children exposed to high maternal BLL in utero, there was a significantly increased risk of having a low PDI up to 36 months of age, in relation to an increasing average calling time (p-trend=0.008). There was also a risk of having decreasing MDI up to 36 months of age, in relation to an increasing average calling time or frequency during pregnancy (p-trend=0.05 and 0.007 for time and frequency, respectively). There was no significant association between child neurodevelopment and prenatal RFR exposure measured by PEM in all subjects or in groups stratified by maternal BLL during pregnancy. ConclusionsWe found no association between prenatal exposure to RFR and child neurodevelopment during the first three years of life; however, a potential combined effect of prenatal exposure to lead and mobile phone use was suggested.

Multiple assessment methods of prenatal exposure to radio frequency radiation from telecommunication in the Mothers and Children's Environmental Health (MOCEH) study.

To evaluate prenatal exposure to radiofrequency radiation (RFR) from telecommunication using a mobile phone questionnaire, operator data logs of mobile phone use and a personal exposure meter (PEM). The study included 1228 mother-infants pairs from the Mothers and Children's Environmental Health (MOCEH) study - a multicenter prospective cohort study ongoing since 2006, in which participants were enrolled at ≤ 20 weeks of pregnancy, with a follow-up of a child birth and growth to assess the association between prenatal environmental exposure and children's health. The questionnaire included the average calling frequency per day and the average calling time per day. An EME Spy 100 PEM was used to measure RFR among 269 pregnant women from November 2007 to August 2010. The operators' log data were obtained from 21 participants. The Spearman's correlation test was performed to evaluate correlation coefficient and 95% confidence intervals between the mobile phone use information from the questionnaire, operators' log data, and data recorded by the PEM. The operators' log data and information from the self-reported questionnaire showed significantly high correlations in the average calling frequency per day (ρ = 0.6, p = 0.004) and average calling time per day (ρ = 0.5, p = 0.02). The correlation between information on the mobile phone use in the self-reported questionnaire and exposure index recorded by the PEM was poor. But correlation between the information of the operators' log data and exposure index for transmission of mobile communication was significantly high: correlation coefficient (p-value) was 0.44 (0.07) for calling frequency per day, and it was 0.49 (0.04) for calling time per day. The questionnaire information on the mobile phone use showed moderate to high quality. Using multiple methods for exposure assessment might be better than using only one method. Int J Occup Med Environ Health 2016;29(6):959-972.

Frequency-Selective Evaluation of Personal Exposure to Electromagnetic Fields of Wireless Communications and Broadcast Transmitters

We performed a frequency-selective measurement campaign using personal exposure meters with a three-axis E-field probe to assess the electric field strength and power density of wireless communication systems and broadcast transmitters in Kosovo. Mean exposure levels were compared among different microenvironments--outdoor urban, living room, office and bedroom microenvironments--in different geographical locations and different exposure time periods. Furthermore, typical exposure levels in European countries and Kosovo were compared. Measurement post-processing results show that the highest values of the mean power density in an outdoor urban microenvironment were 0.173 mW/m2 for Wi-Fi 5G, 0.137 mW/m2 for GSM 900 uplink, 0.128 mW/m2 for GSM 1800 uplink and 0.112 mW/m2 for Wi-Fi 2G. The maximal recorded value of the total electric field strength was 10.44 V/m. The highest exposure levels per frequency band in the living room were 0.042 mW/m2 for FM, 0.023 mW/m2 for GSM 900 uplink and 0.023 mW/m2 for GSM 900 downlink and Wi-Fi 2G. In office environments, the mean power density for 14 predefined frequency bands in the range 88---5850 MHz was 0.227 mW/m2 in total. The highest total electric field strength for office microenvironments was 5.439 V/m. Residential homes were mainly dominated by the GSM bands (GSM 900 downlink, 54 %; GSM 1800 downlink, 36 %). For the frequency bands FM, TETRA and TV4&5, the exposure was much higher on upper residential floors.

Narrowband frequency-selective up-link and down-link evaluation of daily personal-exposure induced by wireless operating networks

The aim of the study is to present a frequency-selective evaluation of personal exposure induced by wireless operating networks in typical daily environments, derived by analysis of 1,905,162 samples of electric field strength, taken at a 5-s sampling interval. Measurements were collected with calibrated isotropic three-axial electric field probe personal exposure meters operating in the frequency range 88---5850 MHz. `' To estimate the electric field distribution below the measurement equipment detection limit, the robust regression on order statistics method was applied, enabling determination of mean values of electric field strength per wireless technology for: home, office, transport, outdoor, and leisure environments. The highest value of total electric field strength exposure is obtained on public transport (buses) followed by coffee shops and outdoor environments, whereas the lowest values are captured in home and office environments. Most of the mean values of the electric field were less than 0.06 V/m. Furthermore, the analyses between the contribution of uplink and downlink exposures for operating wireless cellular networks are given, including a comparison of uplink and downlink electric field levels from other countries. Readings of the 24-h personal-exposure pattern, reveal the GSM + UMTS downlink and Wi-Fi as dominant exposure contributors. The results of this study show that spatial and temporal exposure levels in Kosovo are comparable to those reported for other European countries and far below the international safety guidelines and exposure limits.

THE AGE-DEPENDENCE OF PERSONAL EXPOSURE TO ELECTROMAGNETIC FIELDS OF WIRELESS COMMUNICATIONS IN INDOOR ENVIRONMENTS

The ever-growing usage of new information and communication technology devices by different age groups is followed with public concerns of exposure induced biological effects. The aim of this paper is to assess and compare personal exposure levels to electromagnetic fields of wireless communications for different age groups, including children, under the same exposure conditions. Assessment of personal exposure of the following age groups: 08-15, 16-20, 21-35 and 36-60 years old is conducted with sophisticated tri-axial E-field frequency selective personal exposure meters, enabling measurements of electric field strength in 14 pre-defined frequency bands in the range of 80 MHz-6 GHz. Participants are selected to be with similar social conditions and occupation, including children, students and administrative employees. The measurements were conducted in typical residential environments collecting 161 280 measurement samples. The mean value of power density of different wireless technologies is presented for each age-group, including the contribute of specific wireless technology to the total personal exposure. The highest personal exposure values per frequency band for all age groups are in GSM and Wi-Fi 2G. The results show a difference in mean power density levels between different age groups for the same exposure environment. Ultimately, all measured values were far below international safety guidelines and exposure limits.

Do car-mounted mobile measurements used for radio-frequency spectrum regulation have an application for exposure assessments in epidemiological studies?

Knowing the spatial and temporal trends in environmental exposure to radiofrequency electromagnetic fields is important in studies investigating whether there are associated health effects on humans and ecological effects on plants and animals. The main objective of this study is to assess whether the RFeye car-mounted mobile measurement system used for radio frequency spectrum monitoring in The Netherlands and the United Kingdom could be of value in assessing exposure over large areas as an alternative to measuring exposure with personal exposure meters or using complex modelling techniques. We evaluated the responses of various body-worn personal exposure meters in comparison with the mobile measurement system for spectrum monitoring. The comparison was restricted to downlink mobile communication in the GSM900 and GSM1800 frequency bands. Repeated measurements were performed in three areas in Cambridge, United Kingdom and in three areas in Amersfoort, The Netherlands. We found that exposure assessments through the car-mounted measurements are at least of similar quality to exposure modelling and better than the body worn exposimeter data due to the absence of the shielding effect. The main conclusion is that the mobile measurements provide an efficient and low cost alternative particularly in mapping large areas.