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Electromagnetic fields

The power transmission network in Lithuania operates at the frequency of 50 herz (Hz). All the domestic appliances such as hair dryers, washing machines, fridges, lighting fixtures etc. operate at the same frequency. During operation of any electric equipment, receiver or device – starting from high-voltage power lines and ending with a TV set at home – electromagnetic fields are created and emitted.
 
Natural or artificial electromagnetic fields surround us always and everywhere. While it has not been proven by research that electromagnetic fields present danger to human health, our duty is to inform people about the existence of electromagnetic fields near high-voltage power lines.
 
Parameters of electromagnetic fields in the living environment are strictly regulated
 
The allowable values of electromagnetic fields are established in the Lithuanian legislation. The Lithuanian Hygiene Standard HN 104:2011 “Protection of Residents against Electromagnetic Fields Created by Electric Power Lines” establishes the allowable values of components of electromagnetic fields (electric field strength and magnetic field strength) for the 330 kV and higher voltage overhead lines and related equipment operating at the industrial 50 Hz frequency. These values apply to interiors of residential and public buildings as well as to the environment around such buildings. This Hygiene Standard does not apply to the 110 kV and lower voltage lines due to insignificant values of electromagnetic fields.
 
HN 104:2011 establishes that the allowable strength of electric fields in living environment (i.e. outside the line protection zone) is 1 kilovolt per metre (kV/m), in premises of residential or public purpose 0.5 kV/m; the allowable strength of magnetic fields in living environment is 32 amperes per metre (A/m), in premises of residential or public purpose 16 A/m. This is one of the most stringent hygiene norms in Europe. The allowable values of electromagnetic fields in Lithuania are 2.5 to 10 times lower than those recommended by the European Union institutions. 
 
Document  Electric field strength  Magnetic field strength 
Lithuanian Hygiene Standard 104:2011 applied to living and public premises  0.5 kV/m 16 A/m
Lithuanian Hygiene Standard 104:2011 applicable to living environment  1 kV/m 32 A/m
EU recommendations  1999/59/EC applicable to living environment  5 kV/m 80 A/m
 
Strength of electromagnetic fields decreases rapidly along with the increase in distance from electric equipment 
 
An electromagnetic field consists of an electric field and a magnetic field. Their strength depends on the magnitude of the current flowing in the electric equipment. The greater the magnitude of the current, the stronger the electromagnetic field. The strength of the electromagnetic field is greatest under the high-voltage power line, however, it rapidly decreases as the distance from the electric equipment increases.
 
At the distance of several tens of metres from the power transmission line the strength of the electromagnetic field becomes insignificant.
 
Measurements of electromagnetic fields in Lithuania have shown that the electric field strength at some distance from the power line is 2 to 3 times lower than the allowable value and the magnetic field is 20 to 100 lower than the allowable value. Thus at the distance of just 30 metres or about 50 steps the electromagnetic field is below the set allowable values.
 
The National Public Healthcare Laboratory conducts measurements of electromagnetic fields at residents’ request. Litgrid conducts continuous monitoring of electromagnetic fields created by the high-voltage power lines. Values exceeding the established limits have never been recorded. The power transmission grid is operated in such a way so that the strength of electromagnetic fields is within the allowable limits. 
 
Only electromagnetic fields created by 330 kV overhead power transmission lines can have an impact upon human health; the impact is strongest under the wires, at mid-distance between the towers, at the lowest wire deflection point. Measurements have shown that maximum potential electric strength at this point is 3 to 7 kV/m. There is no regulation of exposure times, however, we recommend that one should not stay under a high-voltage line longer than 5 to 8 hours per day.
 
Electromagnetic fields are emitted by all electric devices to a larger or smaller extent.
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