Mobile phones are one of the biggest source of dangerous electromagnetic radiation today.
In a typical office work the mobile phone and the computer monitor are the two main sources of electromagnetic radiation. According to the work habits and functions, one can be more exposed to radiation from computer's monitor or to that from cell phones.
The name of "cell" phones is a marketing invention, based on the system of antennas that are needed to provide the mobile phone service.
The mobile phone is a complex system, made of fixed antennas, mobile terminals, land-line high speed digital connections, and special computers.
The mobile terminal, which people usually call cell phone or just phone, uses microwave radiation to transmit to and receive from a fixed antenna. The fixed antenna is capable of covering an area from a few hundred meters to a few kilometers wide, according to the system and the location.
The system of land-line connections, supported also by microwave connections between towers, allows to exchange signals between two mobile phones.
Mobile phones are maybe the most diffused product in the world, of the entire history. Today, when the world population is about 7 billions people, there are about 5 billions users of mobile phones, and the number is still growing, in a few years it will probably reach the 99% of the world population.
But mobile phones as electronic devices are extremely dangerous, just as dangerous as they can be without having to be banned completely from the start.
When a mobile phone is inside a typical car, with closed roof, the car becomes filled of electromagnetic radiation of a wide range of frequencies, mostly microwaves, because of the shielding effect of the car's roof and walls. It is almost like to be inside a closed metal chamber. The car's windows let some radiation exit, but most radiated energy remains trapped in the car. The radiation cannot exit from the car and so the levels of electromagnetic fields inside the car increase much, maybe ten times or a hundred times, maybe more, respect to the fields around the cell phone at the open.
Since the car shields the microwave electromagnetic radiation, the cell phone cannot receive the signal from the fixed antenna very well, and so its circuit automatically increases the emitted power, like it does when the mobile phone is taken very far from the fixed antenna in an open terrain.
Even if the user is not using the phone, the mobile phone emits some EMF because it has to keep the contact with the fixed antenna, and the car's effect amplifies this to a high level.
When a mobile phone is brought to a rural place, quite far from buildings, the distance from the nearest cell tower increases, and the mobile phone automatically increases the radiation power to compensate.
In a rural environment, without many buildings, the path of the microwave radiation is straight, from the transmtter antenna to the receiver, there aren't many reflections, so the intensity of the radiation at the receiver decreases approximately with the inverse square of the distance. Corresponding the power radiated by the mobile phone must increase to keep the needed signal level at the receiver, and so the power emitted by the mobile phone increases with the square of the distance from the fixed antenna.
Notice that the small antenna of the mobile phone emits approximately with the same intensity in all directions, not just in the direction of the straight line towards the tower antenna.
If the emitted power increases then also the internal currents from the battery to the emitting circuits increases, and this pulsed current is another source of harmful electromagnetic field for the user.
Such devices should not have been allowed by authorities, but in almost every country the authorities who should prevent such products to be developed and sold are deeply corrupted by the telecom companies.