NON-IONIZING RADIATION MEASUREMENTS IN VOJVODINA

Istvan Bikit, Dusan Mrda,Nebojsa Krstic, Nikola Jovancevic, Mile Ugarcina, Slavko Todorovic

Department of Physics, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia

-The main goal of measurements : Exploration of the existing situation in environment of Vojvodina province, regarding to electromagnetic field levels in the vicinity of sources of non-ionizing radiation, as well as comparison of these values with current legislative

-Also, this exploration should contribute to the analysis of possible ways of future reduction of electromagnetic field intensity in the environment

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-The corresponding measurements are performed in several cities (radio emission antennas are measured in 8 cities ,Cellular phone network stations and transformer stations in 10 cities and high voltage power transmission lines in 12 cities )

-Low-frequency measurements (range: 5 Hz – 100 kHz) covered transformer stations and high-voltage power transmission lines

-Within the high-frequency range (1 MHz – 3 GHz ) the measurements were related to cellular phone network stations and radio emission antennas

- Measurements of electric field strength and magnetic induction are realized at several measurement points around each source of non-ionizing radiation, using equipment for broadband and frequency-selective measurements

● Low-frequency range

- the measurements of electric field strength and magnetic induction are performed by Portable field meter PMM 8053B ( Narda, Italy ) using spectrum analyzer EHP-50C (5 Hz – 100 kHz)

Portable field meter PMM 8053B

spectrum analyzer EHP-50C

-The probe EHP-50C allows measurements of electric or magnetic field components along three spatial axes

-The probe was mounted on tripod made of non-conducting material and connected to the portable field meter by 5m long optical-fiber cable, avoiding the perturbation of electromagnetic field by operator

- Near the transformer stations and high voltage power transmission lines, the dominant frequency of electromagnetic field of 50Hz, as well as several harmonics are detected

-The measured values of electric and magnetic field on these frequencies were found for the probe position of 1m above ground

● High-frequency range

- The broadband measurements of electric field strength in high-frequency range are performed by Portable field meter PMM 8053B and probe EP-300 (100 kHz – 3 GHz)

- Frequency-selective measurements in the high –frequency region are realized by RF Spectrum Analyzer-SPECTRAN HF 2025E (AARONIA, Germany) and Radial Isotropic Broadband antenna – OmniLog 90200 (700 MHz – 2.5 GHz)

- The measurements are performed at 1.5 m height above ground on different distances from the non-ionizing sources

● Results

● Cellular phone network stations

- Maximal values from broadband measurements, found for all locations, were below 2.1 V/m.

The maximal values of electric field strength at certain frequencies ( frequency-selective measurements)

The average values for each location of electric field strength from broadband measurements

Frequency[MHz]

Electric field strength[V/m]

900 16.5

1800 23.3

2000 - 10 000 24.4

Reference values

- average values of electric field strength were below 1.2 V/m.

- Relatively small value of standard deviation of about 85% indicates a reasonable uniformity of emissions of cellular phone network stations on the Vojvodina territory.

● Radio emission antennas

-The radiation of radio emission antennas was measured in 8 cities, where one antenna was selected in each city. The broadband technique is used.

The maximal values of electric field strength(broadband measurements)

Distribution of average values of electric field

-These distributions, together with very small values of standard deviations show that this category of electromagnetic radiation is very uniform in the Vojvodina region.

●High voltage power transmission lines

-The electromagnetic radiation of high voltage power transmission lines was investigated in 10 cities in Vojvodina

-The values of electric field strength and magnetic induction were covered by measurements

Distribution of average values of electric field strength

Distribution of average values of magnetic induction

- The average values of electric field varied significantly among locations, while the variations of magnetic induction were relatively small

●Example of electromagnetic field measurements of 220 kV high voltage power transmission lines No. 127/11 in Novi Sad

- Measurements of electric field strength and magnetic induction are performed at 1m above ground in 21 points along direction perpendicular to the high voltage power transmission lines

Measurement points below high voltage power transmission lines

Distribution of electric field Distribution of magnetic field

●Transformer stations

- Electromagnetic radiation of transformer stations is measured in 12 cities in Vojvodina.

Average values of electric field for transformer stations

Average values of magnetic field for transformer stations

-Very high value of electric field strength is found at one measurement point around transformer station in Vrbas, under the high voltage power transmission lines, where the transmission lines are connected to the transformer station

-This value, which is mainly caused by transmission lines, reached 58% of reference value according to current legislative in Serbia

-At the other locations, the measured maximal values of electric field were much lower, and did not exceed 0.34% of reference value

-The magnetic induction values were much more uniformly distributed than electric field values

Reference values

For f = 50 Hz =0.05 kHz → E REF.= 2000 V/m

-the described system of measurement can provide rough insight in distribution of electromagnetic field intensity on the Vojvodina territory

-the amount of acquired data is not enough for formulation of statistically significant conclusions.

-In recent time the mobile comunications develops intensively, so the cellular phone network stations are perceived in public as the major sources of non-ionizing radiation in the environment

-However, this research shows that all sources of non-ionizing radiation , should be considered with equal and increased attention, having in mind that the health effects of non-ionizing radiation are not well known.

Conclusions