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Mobile Communication Fields in Biological Systems
operator personnel, janitors, painters, chimney sweepers, window cleaners, technical
staff dealing with repair or maintenance of roof, roof-racks, and gutters or with heating, ventilation, and air conditioners). For such situations where exposure levels exceed
the general public limits, there is a need for a careful investigation and clarification of
operational control procedures, measurements, and instructions, elaborated and aimed
to protect the health and safety of workers.
To protect themselves, workers must take into account several issues concerning
their exposure to RF fields emitted by base-station antennas. First, modern base-station
antennas are sector antennas that transmit only in the forward direction. Due to the
high directivity on the vertical plane of the base-station antenna considered, the highest
field levels are not obtained on the roof of the building where the antenna is located, but
rather on the nearby building placed in the direction of the maximum antenna radiation
(Bernardi et al. 2002b). Moreover, when working behind the antenna, it is likely that the
RF fields are at the background level due to the very good directivity of the transmission.
Second, the antenna might be placed on a small mast, chimney, or higher on the building
wall. In this case, the antenna will send the transmission over the heads of people working below antennas. The same principle applies if one is working higher than the antenna.
According to the above, exposure from base-station antennas is low and cannot
represent a risk for human health from the thermal point of view. Only when working very close to the antenna is there a need for precautionary measures. However,
the possibility of long-term nonthermal effects of these fields is an open issue. This
problem can be addressed through epidemiological studies, which, in order to be effective, require an accurate evaluation of the internally induced field (Burgi et al. 2010;
Khurana et al. 2010).
5.4.4. Wi-Fi Systems
Wireless fidelity (Wi-Fi) is a term used to describe the way user terminal equipment (e.g.,
computers, PDAs, pocket PCs, cellular phones) can wirelessly connect to a network in the
absence of a cable infrastructure. Instead, the connection is made using RF EM waves, along
which the data are sent in pulses. This is a relatively new wireless access technology that has
taken off at a rapid pace. The first wireless systems were developed in the early 1990s (e.g.,
WaveLAN). However, it was not until 1999 that wireless technologies were widely accepted.
The most common 802.11g protocol has only been around since 2003. The network device
providing the bridge between the wireless and wired networks is called the Wi-Fi access
point, which is a radio transceiver itself. The user terminal equipment should be equipped
with a wireless network interface card for communication with the access points.
All Wi-Fi wireless products are required to be evaluated to ensure conformance with
the RF emission safety guidelines (ICNIRP 1998; IEEE 2005). These evaluations are done
in accordance with the various regulations and guidelines adopted or recommended
by regulatory agencies around the world. The Wi-Fi Alliance is conducting additional
studies to confirm, in a variety of settings, that RF exposure to Wi-Fi products consistently falls well below the international exposure limits. In addition, the organization is
sponsoring an independent review of the scientific studies that may be relevant to Wi-Fi
products. At the same time, the Mobile Manufacturers Forum and the GSM Association
Mobile Communication Fields in Biological Systems
operator personnel, janitors, painters, chimney sweepers, window cleaners, technical
staff dealing with repair or maintenance of roof, roof-racks, and gutters or with heating, ventilation, and air conditioners). For such situations where exposure levels exceed
the general public limits, there is a need for a careful investigation and clarification of
operational control procedures, measurements, and instructions, elaborated and aimed
to protect the health and safety of workers.
To protect themselves, workers must take into account several issues concerning
their exposure to RF fields emitted by base-station antennas. First, modern base-station
antennas are sector antennas that transmit only in the forward direction. Due to the
high directivity on the vertical plane of the base-station antenna considered, the highest
field levels are not obtained on the roof of the building where the antenna is located, but
rather on the nearby building placed in the direction of the maximum antenna radiation
(Bernardi et al. 2002b). Moreover, when working behind the antenna, it is likely that the
RF fields are at the background level due to the very good directivity of the transmission.
Second, the antenna might be placed on a small mast, chimney, or higher on the building
wall. In this case, the antenna will send the transmission over the heads of people working below antennas. The same principle applies if one is working higher than the antenna.
According to the above, exposure from base-station antennas is low and cannot
represent a risk for human health from the thermal point of view. Only when working very close to the antenna is there a need for precautionary measures. However,
the possibility of long-term nonthermal effects of these fields is an open issue. This
problem can be addressed through epidemiological studies, which, in order to be effective, require an accurate evaluation of the internally induced field (Burgi et al. 2010;
Khurana et al. 2010).
5.4.4. Wi-Fi Systems
Wireless fidelity (Wi-Fi) is a term used to describe the way user terminal equipment (e.g.,
computers, PDAs, pocket PCs, cellular phones) can wirelessly connect to a network in the
absence of a cable infrastructure. Instead, the connection is made using RF EM waves, along
which the data are sent in pulses. This is a relatively new wireless access technology that has
taken off at a rapid pace. The first wireless systems were developed in the early 1990s (e.g.,
WaveLAN). However, it was not until 1999 that wireless technologies were widely accepted.
The most common 802.11g protocol has only been around since 2003. The network device
providing the bridge between the wireless and wired networks is called the Wi-Fi access
point, which is a radio transceiver itself. The user terminal equipment should be equipped
with a wireless network interface card for communication with the access points.
All Wi-Fi wireless products are required to be evaluated to ensure conformance with
the RF emission safety guidelines (ICNIRP 1998; IEEE 2005). These evaluations are done
in accordance with the various regulations and guidelines adopted or recommended
by regulatory agencies around the world. The Wi-Fi Alliance is conducting additional
studies to confirm, in a variety of settings, that RF exposure to Wi-Fi products consistently falls well below the international exposure limits. In addition, the organization is
sponsoring an independent review of the scientific studies that may be relevant to Wi-Fi
products. At the same time, the Mobile Manufacturers Forum and the GSM Association