JEMAAJournal of Electromagnetic Analysis and Applications1942-0730Scientific Research Publishing10.4236/jemaa.2010.23021JEMAA-1540ArticlesEngineering Physics&Mathematics Analysis of the Electromagnetic Pollution for a Pilot Region in Turkey zgurGenc*MehmetBayrakErcanYaldiz** E-mail:ozgurgenctr@yahoo.com(ZG);eryaldiz@gmail.com(EY);120420100203139144November 10th, 2009December 11th, 2009 December 15th, 2009.© Copyright 2014 by authors and Scientific Research Publishing Inc. 2014This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/

In this paper, electromagnetic (EM) pollution (or radiation) measurements in a transmitter region were performed and statistical analysis of values recorded for the EM sources causing pollution was carried out. The actual measurement values and the estimated values by the analysis model obtained through the statistical analysis were compared. EM radiation levels were measured in the districts of Turkish capital Ankara where cellular base stations and TV/Radio stations are densely populated. EM Radiation (EMR) levels were measured for the GSM900, GSM1800, UHF4, VHF4 and VHF5 stations for certain spectrum ranges under far-field conditions by utilizing isotropic field probe and selective spectrum analyzer. The obtained measurement levels were compared with the limit values given by International Commission for Non-Ionizing Radiation Protection (ICNIRP). The results are discussed, regarding both the obtained values that influence the measurements.

Electromagnetic Pollution Statistical Analysis Electromagnetic Radiation1. Introduction

The use of EMR for communication increased significantly in the recent years (radio, television and cellular) and consequently the environmental level of EMR has increased. The massive proliferation of mobile communications equipment raised a special concern regarding the safety of population and personnel exposed to radiofrequency (RF) radiation emitted by either the base-station antennas [1].

The potential health effects of EMR from the transmitters for broadcasting of radio/TV and mobile communication are the subject of on-going researches [2,3] and a significant amount of public debate. The distribution and levels of EM pollution in the crowded residential areas are very important.

Exposure standards for RF region of EM spectrum, applicable at national or international level give for the UHF and VHF band of interest the RMS electric field strength maximum accepted values as reference levels for occupational or population exposure [1] in the far field region of the sources.

EM pollution measurements within the scope of this study were executed in a chosen pilot region, the city centre of Ankara, Turkey. The measurements were specifically in Dikmen Caldagi Hill transmitter region where many EM pollution sources are located.

In the present, there are three public mobile communication operators in Turkey: Vodafone (GSM 900 MHz), Turkcell (GSM 900 MHz), AVEA (GSM 1800 MHz or DCS 1800 MHz).

From the statistical analysis of the measurement results, EM radiation levels can be modeled through various calculations and formulas retrieved under certain conditions and within acceptable correctness. EM pollution measurement results are examined by means of time series analysis whether these results are suitable for predicting through the created model. Estimation or determination of the dependant variable total EM pollution is realized as based on the modeling.

2. Measurement of EM Pollution

In this EM pollution measurement study; it is assumed that only far field conditions exist for the cellular (GSM900 and GSM1800), TV and radio transmitters since these installations are most of the time mounted on high towers or hills.

It is essential to measure the combined field levels for all different signal sources in the environment like as shown Figure 1. In practice, many of the directional antennas with high gains are not suitable for this purpose since they don’t allow measurements of signals from all directions and different polarizations and therefore not

allowing quick measurements. The system we used is designed for measurements of the E-field strength. This ensures that optimum settings are used and allows evaluation according to single frequencies, complete services and total emission. Since the tri-axis sensor (antenna) has got an isotropic characteristic, the measurement is done independent from direction or polarization of the emitter [1].

In the measurements, the wide band spectrum (75 MHz – 3 GHz) antenna probes that can measure from all directions and different polarizations [4,5,6] were used.

The measurements were fulfilled by using NARDA SRM3000 radiation meter with isotropic antenna that can be utilized in 75 MHz – 3 GHz frequency range. The measurement system comprises of an isotropic broad band antenna that is connected via combiner to a portable spectrum analyzer. The electric field probe was based at 2m height from the ground level. The EMR meter was interfaced with a portable computer. Measurement results recorded by using SRM3000 were saved to a computer [5]. Random measurements were performed in the transmitter region, far from GSM base station and radio/TV transmitters in far-field points. The antenna was mounted on a tripod. The signal from the EMR meter is expressed in Volt units convertible to electric field strengths (V/m) using the antenna factor parameter. All measurements were divided according to their relevant frequencies into groups (Radio, TV, Cellular, etc). For each measurement Eaverage (V/m) was recorded [8]. The duration of each measurement was 6 minutes [7,8]. The experimental set-up is depicted in Figure 2.

The measurements include the sources listed in Table 1 and the other sources within the spectrum up to 3 GHz.

3. Statistical Analysis of EM Pollution Measurements

The measurement results are analyzed by means of the SPSS 17.0 and E-views software. Firstly, stability of the obtained time series was examined using Dickey-Fuller (D-F) test in order to determine if the time series are suitable for estimation. In the second stage, the relationship between the variables was examined using correlation and regression analyses. Finally, variance analysis

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