IMA Stand on Mobile Towers

Health Care Comments Off

Radiations: Some key facts

• Cell phones emit radiofrequency energy (radio waves), a form of non-ionizing radiation. Tissues nearest to where the phone is held can absorb this energy.
• Radiofrequency energy is a form of electromagnetic radiation.
• Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g., radiofrequency and extremely low-frequency or power frequency).
• In September 2013, WHO in online question and answers, have mentioned that “Studies to date provide no indication that environmental exposure to RF fields, such as from base stations, increases the risk of cancer or any other disease.”
• In respect of EMF radiations from mobile handsets, WHO in Fact Sheet 193 published in June 2011 has concluded that “A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use”.
• In 2012 WHO declared Radio frequency radiation as a possible carcinogen in human Group (2B).
• SAR is Specific Absorption Rate. It is an indication of the amount of radiation absorbed into the head while using a cellular phone.
• The higher the SAR rating greater radiation is absorbed into the head.
• SAR value is a measure of maximum energy absorbed by a Unit of mass -exposed tissue of a person using a mobile phone over given a time. It is simply the power absorbed per unit mass.
• SAR values are usually expressed in units of watts per kilogram in one gram of tissue.
• As per NICRP, the SAR value in India is 1.6 watt per kg in one g of tissue.
• Low SAR rating is no guarantee of your health.

Safety Measures

• Reduce electromagnetic radiation from a source spreads in electromagnetic Field (EMF becomes weaker and weaker as distance increases. Thus, the distance plays a vital role.

Mobile hand set

• Keep distance: Hold the cell phone away from the body to the extent possible.
• Use a headset (or ear bud) to keep the handset farther from your head.
• Do not press the phone handset against your head. Radiation level is proportional to the square of the distance from the source- being very close increases energy absorption much more. The farther your brain is from the handset the better it is.
• Use a wired headset.
• Limit the length of mobile calls.
• Use text as compared to voice wherever possible.
• Put the cell phone on speaker mode.
• Use a wireless Bluetooth headset.
• If the radio signal is weak, a mobile phone will increase its transmission power. Find a strong signal and avoid movement. Use your phone where reception is good.
• Use the mobile on a speaker mode.
• Metal and water are good conductors of radio waves so avoid using a mobile phone while wearing metal-framed glasses or having wet hair.
• Let the call connect before putting the handset on your ear or start speaking and listening – A mobile phone first makes the communication at higher power and then reduces power to an adequate level. More power is radiated during call connecting time
• If you have a choice, use a landline (wired) phone, not a mobile phone.
• Use mobile when mobile and use stationary phone, when stationary.
• When your phone is ON, don’t carry it in a breast or pants pocket. When a mobile phone is on, it automatically transmits at high power every 1 to 2 minutes to check (poll) the network.
• Reduce mobile phone use by children as a younger person will likely have a longer lifetime exposure to radiation from cell phones
• People having active medical implants should preferably keep the cell phone at least 15 cm away from the implant.
• While purchasing a Mobile Handset, check the SAR value of the mobile phone. This can be searched on internet, if the model number & make is known. Dial *#07# to know the SAR value.
• To lower exposure to radiation, close additional transmissions in the phone like WiFi, Bluetooth, GPS or Data connections when not needed. Additional connections not only drain battery but also dramatically increased device radiation emissions.
• In iphone 6, SAR value can reach 1.59 watt per kg with their transmitters enabled.
• Multiple transmission increase SAR value by up to 40%.
• Try to use the phone outdoors rather than inside. Try move close to a window to make a call.
• Avoid touching the aerial while the phone is turned on
• Keep the phone away from areas of the body such as eyes, testicles, breasts and internal organs.
• Limit the usage if you are pregnant.
• The phone antenna has to perform extra work to arrange communication with the cell tower which increases RF exposure when the battery is lower than 20% the RF exposure increases.
• The RF radiation is increased by mobile phones when used in a car to overcome the shielding.
• Avoid using the phone when you are tired or sleepy.
• Alternate your ear while talking.
• Try not keep your phone in your pocket when you are in the office.
• While sleeping, keep the phone at a distance of 6 ft (2 meter).
• Do not use a metal case as your phone cover.
• RF energy
 is
 inversely
 proportional
to
the
square
of
the 
distance
from
the
 source.
• India
has
adopted
one
of
the
most
stringent electromagnetic
field
 (EMF) 
exposure
norms
in
the
world.
EMF
exposure
limit (Base
Station
Emissions) 
is
lowered
to
1/10th
of
the existing
ICNIRP
exposure
level
effective
from
1st
Sept.
2012.
• 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 used by cell phones and towers are much lower.


Mobile stations

• Radio waves from base stations in India comply with international health and safety guidelines.
• The prescribed safe RF exposure limit is f/2000 (in India), where f is in mHz.
• Exposure limits in India are: At 900 MHz, power density is 0.45 watt/m2 & at 1800 MHz, power density is 0.9 watt/m2.
• It is the antenna from which we should keep distance not from tower and that too if we are positioned facing antenna at comparable height. At the ground level, the intensity of RF radiation from base station is much lesser than that of from Antenna.

Phone vs tower
·
• A mobile handset or a cellular phone is a low-power, two way radio. It contains a transmitter and a receiver. It emits electromagnetic / RF radiation to transmit information to the base station and it also acts like a receiver of information. Radio signals in a mobile phone are generated in the transmitter and emitted through its antenna. The radiation emitted by the antenna is not sufficient to cause any significant heating of tissues in the ear or head, although a rise in skin temperature may occur as a result of placing the mobile phone too close against the ear or head for a long time. This is due to insulation of the phone, contact with the screen, lack of ventilation between the ear and the phone, and the energy generated by electronic components.
• Mobile phone base stations, which are also known BTS, work as multi-channel two-way radios. Antennas, which produce RF radiation, are mounted on either transmission towers or roof-mounted structures. These structures are to be of a certain height so that coverage could be wider. When you communicate on a mobile phone, you are connected to a nearby base station. From that base station your phone call goes into the regular fixed-line phone system.
• Since the mobile phone and its base stations communicate using a two way radio communication, they produce RF radiation to communicate and therefore expose the people near them to RF radiation.
• Radiation emitted from cell phone is of a short-term, repeated nature (coherent) at a relatively high intensity, whereas Radiation emitted from BTS (mobile towers) is of long duration but is of a very low intensity.
• Safety distance to mobile tower antennas or masts: There is a recommended safe distance (i.e. compliance boundary) from the antenna. It ranges from 30 to 75 meters right in front at height comparable to the lowest mobile tower antenna depending upon the number of antennas deployed.

Power

The analog phones are being phased out. The major difference is that analog phones use more power than digital. Analog mobile phone uses up to 2 watt, while a digital mobile phone has an average power level of 0.25 watt. Phones typically operate at much lower levels during normal use as the phone power is automatically adjusted to the minimum radio signal level needed for call quality. This extends battery life.

Cellular phone tower & Radio waves

Mobile phone base stations are radio transmitter with antennas mounted on either transmission towers or roof tops on buildings. The antennas need to be located at optimum locations and heights so they can adequately cover the area. Antenna position usually range in height from 50-200 feet. When a person makes a cell phone call, a signal is sent from the mobile phone’s antenna to the nearest base station antenna. The base station responds to this signal by assigning it an available radiofrequency channel. RF waves transfer the information to the base station. The voice/data signals are then sent to a switching center, which transfers the call to its destination. The voice signals are then relayed back and forth during the call. In India mobile phones operate in the frequency range of:

869 – 890 MHz (CDMA)
935 – 960 MHz (GSM900)
1805 – 1880 MHz (GSM1800)
2110 – 2170 MHz (3G)

Cell phones connect with the base station as frequently as every minute so as to relay information about your location which generates a near-field by the cell phone even when you are not making a call. When you make a call on a mobile phone, the phone transmits radio waves to the antenna of a nearby base station. The base station then transmits the call using the mobile telecommunications network to the phone of the person you are calling. In town and cities where there are many phone users, more base stations are needed than in rural areas. The antenna of the base stations are mounted on mast, buildings or towers. The intensity of the radio waves emitted from base stations in places where the public have access are generally found to be hundreds of times below the health and safety guidelines. The intensity of electro-magnetic wave (power density) weakens very quickly as it moves away from the antenna. It is reduced to ¼ when the distance from the antenna doubles and to 1/9 when the distance is three times.

Do cellular phone towers cause cancer?

Some people have expressed concern that living, working, or going to school near a cell phone tower might increase the risk of cancer or other health problems. At this time, there is very little evidence to support this idea. In theory, there are some important points that would argue against cellular phone towers being able to cause cancer.

• First, the energy level of RF waves is relatively 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.

• A second issue has to do with wavelength. RF waves have long wavelengths, which can only be concentrated to about an inch or two in size. This makes it unlikely that the energy from RF waves could be concentrated enough to affect individual cells in the body.

• Third, 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.

For these reasons, most scientists agree that cell phone antennas or towers are unlikely to cause cancer.

How are people exposed to the energy from cellular phone towers?

As people use cell phones to make calls, signals are transmitted back and forth to the base station. The RF waves produced at the base station are given off into the environment, where people can be exposed to them.

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.

Public exposure to radio waves from cell phone tower antennas is slight for several reasons. The power levels are relatively low, the antennas are mounted high above ground level, and the signals are transmitted intermittently, rather than constantly.

At ground level near typical cellular base stations, the amount of RF energy is thousands of times less than the limits for safe exposure set by the US Federal Communication Commission (FCC) and other regulatory authorities. It is very unlikely that a person could be exposed to RF levels in excess of these limits just by being near a cell phone tower.

When a cellular antenna is mounted on a roof, it is possible that a person on the roof could be exposed to RF levels greater than those typically encountered on the ground. But even then, exposure levels approaching or exceeding the FCC safety guidelines are only likely to be found very close to and directly in front of the antennas. If this is the case, access to these areas should be limited.

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. The energy level behind an antenna is hundreds to thousands of times lower than in front. Therefore, if an antenna is mounted on the side of a building, the exposure level in the room directly behind the wall is typically well below the recommended exposure limits.