WIFI and Your Health

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Gordon Davis
6 years ago
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1 WIFI and Your Health WIFI Operation: WIFI Networking equipment operates within the unlicensed 2.4 and 5.0 GHz frequency bands. These frequency ranges (bands) are available for use in 100+ countries worldwide and are subject to restrictions on power output and antennas that can be utilized to legally operate without a license in each country. Canada Limits on Radio Frequency (RF) Emissions: In Canada, the maximum- allowable RF power transmission for WIFI equipment is 100 Milliwatts (or 1/10 th of a watt). Related to this value is the -maximum- allowable electromagnetic field density that any RF device may emit, which is 1,000 microwatts per square centimeter (1000 uw/cm2) in Canada. Both of these limits are tested prior to products being certified for sale in Canada (and in other countries with their respective limits). RF Emissions Received by Students: Aruba s WIFI networking equipment operates at or below the Canadian Government regulations of RF Emissions at all times, and is certified by Industry Canada for operation throughout the country. Examples of RF Emissions that would be received by students from a WIFI network deployed within a given school are illustrated in the table below. Two power levels of the WIFI network are assumed within the analysis: Maximum of 100 milli-watts (mw), as well as, half that power level (50mW). Further discussion of the relevance of these power levels is provided in the Discussion section of this paper. Distance of a Student from Aruba Access Point RF Emissions received from a WIFI Network at maximum power (Transmit Power = 100mW / 20 dbm) RF Emissions as a Percentage of Canadian Government Regulations (1000 uw/cm2) RF Emissions received from a typical Aruba WIFI Network (Transmit Power = 50mW / 17 dbm) Fraction of Government of Canada Guidelines (1000 uw/cm2) 1 Foot 7.2 uw/cm % 3.6 uw/cm % 1 Meter 0.8 uw/cm % 0.4 uw/cm % 2 Meters 0.2 uw/cm % 0.1 uw/cm % 10 Feet / uw/cm % uw/cm % Meters 10 Meters uw/cm % uw/cm % 20 Meters uw/cm % uw/cm %

2 Discussion on Results: From the table above, it can be noted that: a) the RF emission levels that students receive as a result of being in any proximity of the Wireless LAN (WLAN) network are well within the Canadian government guidelines. Example #1: A student sitting directly under a WIFI access point at a distance of conservatively 1 meter (9 foot ceiling and sitting at desk underneath access point) This student would experience up to 0.08% of the Canadian Government maximum allowable RF emissions exposure, which equates to 0.8 uw/cm2. point was operating at full power. assuming the access If the access point was an Aruba Networks device, the student would receive closer to 0.04%(~half as much RF exposure),, or 0.4 uw/cm2. Other students within the class environment would experience even less RF emissions, as their distance from the access point (Transmitter) would be larger. b) It can be further noted that as distance from the wireless network (which typically is mounted on the ceiling, in the ceiling or 8 feet up on a wall in school settings) exposure diminishes rapidly-. This means the contribution of RF energy from adjacent classrooms (as would be the case when several access points are located within a given school building) is a negligible component in overall exposure. Example #2: Same student sitting directly under a WIFI access point at a distance of conservatively 1 meter (9 foot ceiling and sitting at desk underneath access point) and taking into consideration an access point in the classroom adjacent is also active at a distance of 10 meters from this student at the same time. This student would experience 0.08% of the Canadian Government maximum allowable RF emissions exposure from the access point overhead and worst case an additional % from the WIFI network emanating from the classroom next-door (@ 10 meters distance). The total exposure can be calculated as: : = % of f the Canadian government regulated emissions level,, which equates to uw/cm2. In practice, at least some RF energy would actually be blocked by the wall materials separating the classrooms, reducing the students net- exposure even further. Aruba Network s Advanced RF Capabilities: Aruba s WIFI networking equipment is well respected within the Wireless LAN (WLAN) industry as a leader in adaptive RF management. One of the most important features that Aruba has implemented into it s product is the ability for every- Aruba WIFI access point, including those deployed throughout the school district, to automatically and dynamically adjust RF power levels based on an as-needed basis.

3 The net-result, is that an Aruba Networks WIFI deployment rarely- will actually transmit at the limits described above as the Canadian government maximum (100mW). Instead, the Aruba WIFI network will auto-adjust itself and in the vast majority of cases to operate on average at 50% of the maximum power level (50 milliwatts). This is in contrast to many other vendor solutions in the market today that operate at high (maximum) power levels on a routine basis. These vendors include those touting single cell technologies, and those that endeavor to focus beams of RF energy directly at users/students. Conclusions: As the school district deploys the Aruba Networks WIFI solution exclusively, it can thus take full advantage of the intelligent adaptive RF algorithms Aruba has developed to minimize RF exposure to the lowest levels in the industry. The RF emissions from the Aruba WIFI network,, as illustrated above, are well under 0.08% ( <0.8 uw/cm2) of Canadian Government Regulatory Levels(1000 uw/cm2) at distances as close as 1 meter from the WIFI network, and diminish very rapidly as distance from an access point increases.

4 Emissions and Common Consumer Device Types iphone Perspective Health & Safety Guidelines rtant_product_information_guide.pdf ipad Perspective Health & Safety Guidelines

5 BlackBerry Perspective Health & Safety Guidelines Android Perspective Health & Safety Guidelines DROID_ERIS_Verizon_English_UM_11_5.pdf

6 REFERENCES Government of Canada -- Safety Code 6 Guidelines. 1mW/cm2 = 1000uW/cm2 d_2009.pdf

R ICHARD T ELL A SSOCIATES, INC.

R ICHARD T ELL A SSOCIATES, INC. Supplemental Report on An Analysis of Radiofrequency Fields Associated with Operation of the PG&E SmartMeter Program Upgrade System October 27, 2008 Prepared for Pacific