Olongapo Telecom & Information Technology

Wednesday, September 02, 2009


Electromagnetic fields and public health


Mobile telephony is now commonplace around the world. This wireless technology relies upon an extensive network of fixed antennas, or base stations, relaying information with radiofrequency (RF) signals. Over 1.4 million base stations exist worldwide and the number is increasing significantly with the introduction of third generation technology.

Other wireless networks that allow high-speed internet access and services, such as wireless local area networks (WLANs), are also increasingly common in homes, offices, and many public areas (airports, schools, residential and urban areas). As the number of base stations and local wireless networks increases, so does the RF exposure of the population. Recent surveys have shown that the RF exposures from base stations range from 0.002% to 2% of the levels of international exposure guidelines, depending on a variety of factors such as the proximity to the antenna and the surrounding environment. This is lower or comparable to RF exposures from radio or television broadcast transmitters.

There has been concern about possible health consequences from exposure to the RF fields produced by wireless technologies. This fact sheet reviews the scientific evidence on the health effects from continuous low-level human exposure to base stations and other local wireless networks.

In fact, due to their lower frequency, at similar RF exposure levels, the body absorbs up to FIVE TIMES more of the signal from FM radio and television than from base stations/Cellsites. This is because the frequencies used in FM radio (around 100 MHz) and in TV broadcasting (around 300 to 400 MHz) are lower than those employed in mobile telephony (900 MHz and 1800 MHz) and because a person's height makes the body an efficient receiving antenna. Further, radio and television broadcast stations have been in operation for the past 50 or more years without any adverse health consequence being established.

Cancer: Media or anecdotal reports of cancer clusters around mobile phone base stations have heightened public concern. It should be noted that geographically, cancers are unevenly distributed among any population. Given the widespread presence of base stations in the environment, it is expected that possible cancer clusters will occur near base stations merely by chance. Moreover, the reported cancers in these clusters are often a collection of different types of cancer with no common characteristics and hence unlikely to have a common cause.

Scientific evidence (from studies by National Cancer Institute) on the distribution of cancer in the population can be obtained through carefully planned and executed epidemiological studies. Over the past 15 years, studies examining a potential relationship between RF transmitters and cancer have been published. These studies have NOT provided evidence that RF exposure from the transmitters/Cellsites increases the risk of cancer.

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Many scientific studies have investigated possible health effects of mobile phone radiations. These studies are occasionally reviewed by some scientific committees to assess overall risks. The most recent assessment was published in 2007 by the European Commission Scientific Committee on Emerging and Newly Identified Health Risks. It concludes from the available research that no significant health effect has been demonstrated from mobile phone radiation at normal exposure levels:

Normal exposure to mobile phone radiation cannot cause headaches or dizziness, nor can it cause brain cancers, neurological effects or reproductive effects.

The World Health Organization, based upon the consensus view of the scientific and medical communities, states that cancer is unlikely to be caused by cellular phones or their base stations and that reviews have found no convincing evidence for other health effects


Radiation absorption

Part of the radio waves emitted by a mobile telephone handset are absorbed by the human head. The radio waves emitted by a GSM handset, can have a peak power of 2 watts, and a US analogue phone had a maximum transmit power of 3.6 watts. Other digital mobile technologies, such as CDMA2000 and D-AMPS, use lower output power, typically below 1 watt, UVA. The maximum power output from a mobile phone is regulated by the mobile phone standard it is following and by the regulatory agencies in each country

The cell phone and the base station or CELL SITE check reception quality and signal strength and the power level is increased or decreased automatically, within a certain span, to accommodate for different situations such as DISTANCE FROM SITE, inside or outside of buildings and moving vehicles.

Which simply means that it is to the advantage of a user/consumer if they are within a reasonable distance from a cell site.

The health risks (ON-LINE ENCYCLOPEDIA)

Despite extensive research on the subject, there has been no conclusive evidence that using a mobile phone causes long term harmful effects in humans.

Mobile phone antennas, base stations and CELL SITES

There's been a lot of controversy about radio antennas, mobile phone antennas and their emissions causing leukemia and other diseases. (Note it is the actual antenna itself that emits radio waves, not the structure that supports it.) The truth is, there is no conclusive evidence one way or the other, but here are few facts about levels of radiation transmission from mobile phone antennas:

• to get a dose of radiation considered dangerous from a mobile/cell phone transmission antenna, you'd have to be almost touching it

• the antennas don't beam directly down so don't 'blow' radiation directly onto us below and the towers that support the antennas don't emit radiation

• radiation dramatically and rapidly decreases as you move away from the mast - 10 meters away, the dose is 0.1% of what it was at 1 meter away; 0.0125% at 20 meters away and so on, thus a 50 watt antenna has the effect of only 0.6 watt at 20 meters away. In contrast DZRH emits 50 Kilowatt power yet there is no documented cancer case caused by its transmission.

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