Cellular Phones
Cellular (cell) phones first became widely available in the United States in the 1990s, but their use has increased dramatically since then. According to the Cellular Telecommunications & Internet Association, there were more than 320 million cell phone subscriptions in the United States as of June 2011, which is actually more than the entire US population. Along with the large and still growing number of cell phone users (both adults and children), the amount of time people spend on their phones has also risen sharply in recent decades.
Cell phones give off a form of energy known as radiofrequency (RF) waves, so some concerns have been raised about the safety of cell phone use. With respect to cancer, concern focuses on whether cell phones might increase the risk of brain tumors or other tumors in the head and neck area.
?? How do cell phonesrk
Cell phones work by sending signals to (and receiving them from) nearby cell towers (base stations) using RF waves. This is a form of electromagnetic energy that falls between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, RF waves are a form of non-ionizing radiation. They don't have enough energy to cause cancer by directly damaging the DNA inside cells. RF waves are different from stronger (ionizing) types of radiation such as x-rays, gamma rays, and ultraviolet (UV) light, which can break the chemical bonds in DNA.
At very high levels, RF waves can heat up body tissues. (This is the basis for how microwave ovens work.) But the levels of energy given off by cell phones are much lower, and are not enough to raise temperatures in the body.
??How are people exposed
The RF waves from cell phones come from the antenna, which is part of the body of a hand-held phone. The waves are strongest at the antenna and lose energy quickly as they travel away from the phone. The phone is typically held against the side of the head when in use. The closer the antenna is to the head, the greater a person's expected exposure to RF energy. The body tissues closest to the phone absorb more energy than tissues farther away.
Many factors can affect the amount of RF energy to which a person is exposed, including:
The amount of time the person is on the phone.
Whether or not the person is using the speaker mode on the phone or a hands-free device. Using one of these allows the phone to be held away from the head.
The distance and path to the nearest cell phone tower. Cell phones adjust their power to use the minimum amount for a good signal, so being farther away from the tower requires more energy to get a good signal, as does being inside a building.
The amount of cell phone traffic in the area at the time. Higher traffic may require more energy to get a good signal.
The model of phone being used. Different phones give off different amounts of energy.
Cellular (cell) phones first became widely available in the United States in the 1990s, but their use has increased dramatically since then. According to the Cellular Telecommunications & Internet Association, there were more than 320 million cell phone subscriptions in the United States as of June 2011, which is actually more than the entire US population. Along with the large and still growing number of cell phone users (both adults and children), the amount of time people spend on their phones has also risen sharply in recent decades.
Cell phones give off a form of energy known as radiofrequency (RF) waves, so some concerns have been raised about the safety of cell phone use. With respect to cancer, concern focuses on whether cell phones might increase the risk of brain tumors or other tumors in the head and neck area.
?? How do cell phonesrk
Cell phones work by sending signals to (and receiving them from) nearby cell towers (base stations) using RF waves. This is a form of electromagnetic energy that falls between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, RF waves are a form of non-ionizing radiation. They don't have enough energy to cause cancer by directly damaging the DNA inside cells. RF waves are different from stronger (ionizing) types of radiation such as x-rays, gamma rays, and ultraviolet (UV) light, which can break the chemical bonds in DNA.
At very high levels, RF waves can heat up body tissues. (This is the basis for how microwave ovens work.) But the levels of energy given off by cell phones are much lower, and are not enough to raise temperatures in the body.
??How are people exposed
The RF waves from cell phones come from the antenna, which is part of the body of a hand-held phone. The waves are strongest at the antenna and lose energy quickly as they travel away from the phone. The phone is typically held against the side of the head when in use. The closer the antenna is to the head, the greater a person's expected exposure to RF energy. The body tissues closest to the phone absorb more energy than tissues farther away.
Many factors can affect the amount of RF energy to which a person is exposed, including:
The amount of time the person is on the phone.
Whether or not the person is using the speaker mode on the phone or a hands-free device. Using one of these allows the phone to be held away from the head.
The distance and path to the nearest cell phone tower. Cell phones adjust their power to use the minimum amount for a good signal, so being farther away from the tower requires more energy to get a good signal, as does being inside a building.
The amount of cell phone traffic in the area at the time. Higher traffic may require more energy to get a good signal.
The model of phone being used. Different phones give off different amounts of energy.
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