Cellular Phone Towers
Cellular (cell) phones first became widely available in the United States in the 1990s, but since then their use has increased dramatically. The widespread use of cell phones has led to cell phone towers being placed in many communities. These towers, also called base stations, have electronic equipment and antennas that receive and transmit radiofrequency (RF) signals.
How do cellular phone towers work?
Cell phone base stations are nothing but free-standing towers or mounted on existing structures, such as trees, water tanks, or tall buildings. The antennas need to be high enough to adequately cover the area. Base stations are usually from 50-200 feet high.
Cell phones communicate with nearby cell towers mainly through radio frequency (RF) waves, a form of energy in the electromagnetic spectrum between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, they are forms of non-ionizing radiation that do not directly damage the DNA inside cells, which is how stronger (ionizing) types of radiation such as x-rays, gamma rays, and ultraviolet (UV) light are thought to be able to cause cancer.
At very high levels, RF waves can heat up body tissues. But the levels of energy used by cell phones and towers are much lower.
When a person makes a cell phone call, RF waves transfers the voice information to the base station. The voice signals are then sent to a switching centre, which transfers the call to its destination. Voice signals are then relayed back and forth during the call.
How are people exposed to the energy from cellular phone towers?
Signals are transmitted back and forth to the base station on the usage of cellular phones. People are exposed to the RF waves produced at the base stations that are given off into the environment. The energy from a cellular phone tower antenna, like that of other telecommunication antennas, is directed toward the horizon (parallel to the ground), with some downward scatter. Base station antennas use higher power levels than other types of land-mobile antennas, but much lower levels than those from radio and television broadcast stations. The amount of energy decreases rapidly as the distance from the antenna increases. As a result, the level of exposure to radio waves at ground level is very low compared to the level close to the antenna.
The level of RF energy inside buildings where a base station is mounted is typically much lower than the level outside, depending on the construction materials of the building. Wood or cement block reduces the exposure level of RF radiation by a factor of about 10.
Do cellular phone towers cause cancer?
In theory, there are some important points that would argue against cellular phone towers being able to cause cancer.
Firstly, the energy level of radio frequency (RF) waves is comparatively low, especially when compared with the types of radiation that are known to increase cancer risk, such as gamma rays, x-rays, and ultraviolet (UV) light. The energy of RF waves given off by cell phone towers is not enough to break chemical bonds in DNA molecules, which is how these stronger forms of radiation may lead to cancer.
The second issue being wavelength. RF waves have long wavelengths, which can only be concentrated to about an inch or two in size. Thus this makes it unlikely that the energy from RF waves could be concentrated enough to affect individual cells in the body.
Lastly, even if RF waves were somehow able to affect cells in the body at higher doses, the level of RF waves present at ground level is very low – well below the recommended limits. Levels of energy from RF waves near cell phone towers are not significantly different from the background levels of RF radiation in urban areas from other sources, such as radio and television broadcast stations.
Cellular Phone Towers