1772044ce45dd636f38fbc3059bf53aa.ppt
- Количество слайдов: 17
Challenges of Mobile Phone SAR Enforcement in Africa Dr. Ally Y. Simba Tanzania Communications Regulatory Authority
Introduction ØMany people want to know: ØAre mobile phones safe? ØAre base station safe? ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 2
EMF Exposure Safety Ø General Conclusion of Expert Scientific Reviews v According to International guidelines, the only scientifically established adverse health effect of RF energy in the human body is thermal, and its safety limits are given based on Specific Absorption Rates (SARs) v No credible evidence that RF exposure within Internationally accepted limits causes any adverse health effects ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 3
SAR Basics ØSpecific Absorption Rate (SAR) is the rate at which RF energy is absorbed per unit mass of a biological body where s, r are conductivity and density [W/kg] of the material, respectively and Et is the total electric field in a biological body u SAR and Temperature Relationship Pennes bio-heat equation Here T represents the temperature of the tissue in degrees Celsius, ρ is the material density (kg/m 3), c is the heat capacity (J/kg/o. C), k is thermal conductivity (W/m/°C), w is the perfusion by blood (m. L/g/s), and Qm is the heat generated by metabolism(W/m 3). The term Tcore represents the core, or arterial, temperature of the body.
SAR Basics q SAR depends on the following üIncident field parameters - frequency, intensity, polarization source-object configuration (near- or far-field) üCharacteristics of the exposed body - size, internal and external geometry electrical properties of various tissues üGround effects and reflector effects of the objects in the field near the exposed body q Averaged SAR üSAR is usually averaged over a certain weight ü 10 -g Averaged SAR ü Whole Body Averaged SAR (WBA-SAR) 14: 23 ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 5
Mobile SAR Limits According to ICNIRP Guideline Ø Localized Exposure § Mobile phone exposure is categorise as localized exposure, i. e. , only part of the body is exposed during use § The safety limit of the localized exposure, according to ICNIRP is given: General Public: 10 -g averaged SAR = 2 W/kg u Occupational: 10 -g averaged SAR = 10 W/kg u ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 6
Mobile SAR Limits According to ICNIRP Guideline ü The limits were obtained based on the eye experiment – Human eye is about 10 -g – Because of the lack of blood flow in the eye, there is low heat dissipation – Considered to be a part that is most affected in body ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 7
Mobile Phone SAR Enforcement üMobile phone manufacturers are required to ensure that their phones comply with these objective limits for safe exposure üManufactured phones, before put in to market they must under go a compliance test üPhone considered safe to be legally sold in the US and EU have FCC ID and EC mark in the phone case, usually below the battery üThe SAR values of mobile phones are available on the internet or you can find them on the specification sheet when you buy it ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 8
SAR Enforcement in Africa Ø Enforcement base on manufacturer compliance test and FCC or EU marking in the SAR the phone works fine in US, America and other country where strong legal systems exist, and illegal importation is almost impossible Ø However, this approach is not effective in most of the African countries ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 9
SAR Enforcement in Africa u The case of Counterfeit Phone üThe cell of counterfeit phone is growing problem in Africa üThese fake handsets are manufactured in a back office some where in Asia and make their way to Africa countries üDue to this fact, manufacturer compliance test cannot be used as an enforcement mechanism because even SAR value indicated in these phone may be also fake üThis problem has increased public anxiety to the public on the safety of mobile phones üIt should be noted here that, the SARs of counterfeit phones do not necessarily exceed the safety limits ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 10
Possible Solution ü The regulators should provide measured SAR of phones in the market annually ü This can be done by taking sample phone in the market ü Compare the SAR values in the phone manual and measured ones ü Inform the public of this information through seminar, workshop and stake holder meeting and by publishing them in the website for public to access ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 11
SAR Measurements Approach I ü Regulators need to build Type Approval Laboratories (TAL) with mobile phone SAR testing capabilities ü This is very expensive project, you will need at least the following facilities and equipments. Most of these equipments are very expensive - EMC Chamber - Mobile Phone Base Station Simulator - SAR Measurement System ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 12
SAR Measurements Approach I Taken from EMF Explained Series ü For example; SAR testing System alone cost up to € 400, 000 EU and annual cost of € 100, 000 for maintenance and calibrations depending on the number of accessories
SAR Measurements Approach I ü Good news is less expensive testing system are developed. ü Some of this do not required expensive industrial-sized robot like those used in the conventional system, hence less expensive SARA – C (Index SAR, UK) i. SAR system (SPEAG, Switzerland) ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 14
SAR Measurements Approach II ü SAR measurements foreign laboratory ü In this case the regulator will collect sample phones from the market and send them to foreign country for measurements ü Although the cost for SAR measurement per phone has not been determine yet, this may be the short solution as the regulators are building long term solution of building long term capacity in equipment and human resource ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 15
Conclusion Ø The issue of mobile phone generate a lot of anxiety to public in many African Countries v v In order to minimize the public anxiety, the SAR of of the mobile phone should be measured and the values made available to the general public There is no short cut in the SAR measurements in Africa, Regulatory bodies should buy and install SAR Measurements Systems or outsource the exercise in foreign countries for few phones sampled in their market so that to satisfy the public ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 16
Thank you for your kind attention contact: simba@tcra. go. tz ITU Workshop on tackling climate change and SAR Measurement: Benin, July 19, 2011 17
1772044ce45dd636f38fbc3059bf53aa.ppt