Application of Time-Averaged and Integral-Based Measure for Measurement Results Variability Reduction in GSM/DCS/Umts Systems

Abstract

Since EMF levels from wireless telecommunication networks are non-stationary and exhibit large temporal variations, the use of continuous measurements during extended periods (preferably 24 h or longer) with a data-logging system is required. Because of the short-term variations of E field, the 6-min measurements and 6-min averaged results to obtain the mean level strength at a given place appear to be dependent on the time of measurements during the day. This paper presents a new (integral-based) measure to evaluate electromagnetic exposure. The new measure is a pure physical descriptor of the amount of exposed energy density (a parameter accumulated from instantaneous power density values in time). To confirm previous observations, continuous measurements with personal exposure metre were recorded 24 h a day for two weeks at every location in urban area, 14 different locations in total. Additionally, to check temporal variations and repeatability of exposure assessment, a week of prolonged measurements was taken 6 months later, making in total three weeks of measurements at 2 locations. Day-to-day repeatability of RF-EMF exposure was analysed through the time-averaged and integral-based measure. The analysis is based on approximately 5.1 million data samples (1.7 million for each band). The ratio between the maximum and minimum instantaneous (maximum and minimum 6-min averaged) E field values during the day could reach up to 25 dB (20 dB). Therefore, great variability in the results may occur. By applying the 24 h time-averaged and integral-based measure on a 24 h data set of measurements, the variability of daily exposure could stay within ±20% of the week mean level obtained either with the time-averaged or integral-based measure. Both, the time-averaged E field and integral-based power density exposures of the general public in all locations were found to be well below the general public exposure limits of the ICNIRP guidelines.

In-Situ RF Measurements of EMFs for Human Exposure Assessment Due to Modern Cellular Base Stations

“…As matter of fact, due to the fast evolution of modern communication technologies, these technical standards are updated also on the basis of many researchers working in this framework, and several members of TC-37 are engaged in this important topic [24]- [26].…”

Is It Safe Living in the Vicinity of Cellular Towers? Analysis of Long-Term Human EMF Exposure at Population Scale

“…In this work, we are interested in analyzing the long-term average exposure of EMFs over the population. Therefore, we discard option (i), since the RFSs are in general subject to large variations of the radiated EMF over time [6]. As a consequence, the adoption of the maximum EMF over the whole interval would lead to an over-estimation of the actual levels of long-term exposure.…”

“…We consider in this step the most conservative assumption in terms of minimum EMF, i.e., F MIN =0.5 [V/m]. 6 Fig. 4(a) reports the average EMF levels and the confidence intervals (with 95% of confidence level) for each category.…”

“…Additionally, we plan to study the difference in exposure levels between the different areas of the territory, as well as a better assessment of indoor vs. outdoor EMF measurements. Finally, we plan to integrate more complex metrics, like integral-based ones [6], in our analysis.…”

“…Previous works in literature target specific aspects of the problem, which include e.g., the evaluation of the exposure over limited zones of the territory [5] (e.g., single cities), a limited set of targeted mobile technologies [6], [7] (e.g., only 3G and/or only 4G), and/or measurements performed over a limited amount of time [8], [9]. Although we recognize the importance of such previous studies, in this work we go five steps further by: (i) considering a very large dataset made available by the Regional Environmental Protection Agency (ARPA) [10], spanning over almost 20 years of measurements that were performed on a vast Italian region, which is covered by multiple operators and by multiple mobile technologies (from 2G up to 4.5G); (ii) analyzing how much the measured EMF levels are affected by the distance between the measurement point and the closest BS(s); (iii) comparing the BS exposure against other EMF sources (e.g., Radio/TV repeaters) that are installed close to users; (iv) evaluating how much the deployment of subsequent BS technologies (e.g., 3.5G, 4G, 4G+) and the EMF regulation updates over the years have impacted the EMF exposure levels in proximity to the BSs; (v) investigating the evolution of the EMF exposure for the population living close to BSs during the next 20-30 years, by assuming that the EMF levels will continue to increase with the current trends.…”