Frequently asked questions

-What is project pedion24?

The scope of pedion24 project is continuous monitoring (on a 24 hour basis) of environmental levels of electromagnetic radiation in various areas of Greece and result publishing and presentation through the web. The system consists of monitoring stations installed in various locations and equipped with certified electric field probes which every 6 minutes measure and store in the station's memory an electric field value. Every 24 hours the stations use the GSM network to communicate with a control centre and send the daily collected data. The data is then processed and published on the web.

-What is referred to as electromagnetic radiation?

Electromagnetic radiation is a propagating wave in space with electric and magnetic components. These components oscillate at right angles to each other and to the direction of propagation. The wave travels at the speed of light. Electromagnetic radiation can be found on the environment in different forms: Infrared radiation, visible light, x-rays are all part of the electromagnetic spectrum as well as electric and magnetic fields of electrical railways and power lines. Radiation emitted from cellular phones and cellular telephony base stations is also electromagnetic radiation at the frequency band of 900-1800MHz. Generally, electromagnetic radiation is classified by frequency and energy.

ΜEmitted radiation can also be classified as non-ionising or ionising. Ionising radiation is characterized of very high frequencies and carries enough energy to ionise an atom (that is, to completely remove an electron from its orbit). Therefore, ionising radiation has biological effects (can damage living cells and tissues). Examples of ionising radiation are ultraviolet radiation, x-rays and gamma radiation emitted from radioactive materials. Non-ionising radiation, on the contrary, refers to any type of electromagnetic radiation that does not carry enough energy to ionize living material - that is, to completely remove an electron from an atom. Examples of ionising radiation are visible light, infrared radiation, radiowaves and microwaves. Emissions from FM and AM radio antennas, television antennas, mobile telephony base station antennas, satellite systems and radars are non-ionising radiation. The following image demonstrates the electromagnetic spectrum:

Electromagnetic radiation can be described using the following quantities:
- Electric Field Intensity (unit is Volt per metre – V/m)
- Magnetic Field Intensity (unit is Ampere per metre – A/m)
- Magnetic Induction (unit is Tesla)
- Power Flux Density (unit is Watt per square metre – W/m²)
The best method to quantify electromagnetic radiation of radiowaves and microwaves is by measuring electric field intensity. Monitoring stations of pedion24 system measure electric field intensity every 6 minutes 24 hours a day.

-Are there any limitations of human exposure on electromagnetic fields?

Yes. The Council of European Union has issued a recommendation on the “Limitation of Exposure of the General Public to Electromagnetic Fields (0 Hz to 300 GHz)” which establishes basic restrictions and reference levels for electric, magnetic and electromagnetic fields. The Greek state based on that recommendation has issued a law that also sets reference levels for electromagnetic fields.

-What do the system’s stations monitor?

Monitoring stations monitor on a 24 hour basis environmental levels of electromagnetic radiation i.e. measure electric field intensity in the spectral band from 100 kHz to 3GHz. In this band operate most of wireless telecommunications services in Greece. In particular, on this frequency band operate FM radio and television stations, cellular telephony networks (GSM, DCS, UMTS), security services networks (TETRA), computer wireless networks (Wi-Fi) and other services. Therefore, pedion24project offers complete information on electromagnetic radiation levels caused by the sources mentioned above.

-Who developed and operates the system?

pedion24project was developed by the Mobile Radiocommunications Laboratory of the National Technical University of Athens and the Radiocommunications Laboratory of the Aristotle University of Thessaloniki. Monitoring stations were provided by Cosmote. Operation and maintenance of the system is also performed by Mobile Radiocommunications Laboratory which ensures measurement integrity and instrument certification.