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Abstract Electromagnetic Radiation Hazards and Protection Methods Ved Prakash Sandlas Principal Advisor, Cogent EMR Solutions Ltd, New Delhi Ex Distinguished Scientist and Chief Controller R&D, DRDO HQ,
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Abstract Electromagnetic Radiation Hazards and Protection Methods Ved Prakash Sandlas Principal Advisor, Cogent EMR Solutions Ltd, New Delhi Ex Distinguished Scientist and Chief Controller R&D, DRDO HQ, New Delhi Seriousness of electromagnetic radiation (EMR) hazards to biological systems has started getting noticed in the recent times. Several studies have demonstrated short term and medium term effects of these radiations on animals and human beings. While international standards have been evolved to maintain safe radiation levels in inhabited areas, no guidelines have been recommended for such purpose in India. It is better to take precautions and adopt measures and protection methods to save human beings from harmful effects of electromagnetic radiation. Protection methods such as radiation shielding of cell phones and microwave ovens; conducting paints and films for buildings and windows; filters and absorbers, etc. are now commercially available to control radiation effects. However, without strict laws and standards to control harmful radiation levels, the situation may become out of control. Key Words EMR Hazards, Health Effects of EMR, Electromagnetic Radiation Effects, Cell Phone Radiation, Microwave Radiation, EMI, EMC. Introduction Effects of harmful electromagnetic radiations on biological systems, particularly human beings, and sensitive electronic equipment have started engaging significant attention of general public during the last few years. Radio Noise, Electrical Noise, Radio Frequency Interference (RFI) and Electromagnetic Interference (EMI) are all kinds of environmental pollution or electromagnetic pollution, polluting the very limited natural resource: Radio Spectrum. Till recently, continuous exposure to radio waves was localized to areas near broadcasting stations, radars, radio communication terminals, etc. the related radiations were not adversely affecting general public in residential areas, hospitals, schools, etc. The situation has changed significantly during the last few years with the proliferation of cell phones, particularly due to the related tower-mounted base station nodes. Other elements of concern are microwave ovens, wireless networking of computers, Bluetooth, cordless phones, etc. Power transmission lines in residential areas are also sources of significant harmful radiation. Scientific studies have demonstrated short term and medium term effects of EMR on animals and human beings; children, weak, sick, or old persons and small animals are particularly vulnerable. Of course, debates are going on as to whether these effects are temporary or permanent. It is suspected that disappearance of butterflies and sparrows from Delhi and its gardens may be related to the high level of electromagnetic pollution. There is a strong feeling that even global warming may be related to excessive radiation levels. Safe levels of microwave radiations fields have been recommended by several studies; these vary from 1 µv/m 2 for sleeping areas and 10 µv/m 2 for other living and working areas to as much as 1000 µv/m 2. However, radiation levels even higher than 5000 µv/m 2 have been monitored at busy market places, main road junctions, near hospitals, office complexes, etc. In India, there are no laws to control electromagnetic radiation levels or any guide lines to maintain reasonable safe levels. It is very easy to understand water, air or noise pollution or contamination. However, electromagnetic pollution is very much esoteric; it is not easily seen, tasted, smelled or felt; but it can be more damaging, some thing like a silent killer. Radio is just 112 years old; its harmful impacts are now only visible. In May 1895, Sir J C Bose reported his legendary work at 50 GHz to the Asiatic Society of Bengal at Calcutta and demonstrated that 'electric (radio) waves possessed all the characteristic optical properties of light waves'. Subsequently, Marconi commercially exploited radio for long distance communications. However, use of electromagnetic waves for short distance wireless links, on continuous 24x7 basis, is a recent development, because of devices such as mobile phones, TV remotes, cordless phones, WIL, WiFi, WiMAX, Bluetooth, etc. Electromagnetic Spectrum Frequency Designation Abbreviation 3-30 Hz Sub-Audio Extremely Low Freq SAF ELF Hz Super Low Freq SLF Hz Voice Ultra Low Freq VF ULF 3-30 khz Very Low Freq VLF khz Low Frequency LF khz Medium Freq. MF 3-30 MHz High Frequency Short Waves HF MHz Very High Freq. VHF MHz Ultra High Freq Microwaves UHF 3-30 GHz Super High Frequency SHF C, X, Ku GHz Extremely High Frequency EHF MMW GHz Sub Millimetric Sub MMW THz Infra Red IR THz Visible λ = nm THz Ultra Violet (UV) λ = nm PHz X-Rays 3x Hz Gamma Rays Cosmic Rays Hz World Resonance Electromagnetic Radiation (EMR) Hazards It is normal to get irritated by nuisance created by buzzing or crackling radio noise generated by electric shaver, mixer or blender and vacuum cleaner; TV disturbance from an automobile idling just outside the house or apartment; or background sound from neighbor s telephone when using cordless phone. This kind of persistent EMI disturbance (or high EMR) is not good for sensitive electronic instruments, or health of humans (in fact all living things). It is advisable not to use cell phone in aircraft or near ICU (intensive care unit) in a hospital. Long duration use of cell phone by children, keeping it in the breast pocket or near genitals, is also not advisable. Yes, these are potential EMI Hazards or Electromagnetic Radiation (EMR) Hazards. Other Potential EMR Risks are: going near or peeping-in microwave oven when it is ON or within a few seconds of switching it OFF, radars, microwave or cell phone towers, high power radio stations, electrical power sub-stations or over-head transmission lines. In the ICU of a modern hospital, using all kinds of sensitive electronic equipment, EMI could be a potential killer unless appropriate precautions are taken. Pacemaker exposure to TV fields can be disturbing and risky. Regular electromagnetic exposure of lower animals, vegetation, some chemicals, paints, etc. have demonstrated degradation. In the aerospace field, EMI could lead to catastrophes; missiles may miss-fire; satellites may lose control; electro-explosives could get initiated at wrong times. There is an interesting case of a Sounding Rocket taking off, when the siren was switched ON. Inertial platform of Satellite Launch Vehicle SLV-3 demonstrated high drift because of RF interference from VHF telemetry transmitter. AGNI missile complex timing clock started jumping because of interference from communication systems and grounding configuration. Space and defence systems have evolved sophisticated EMI control and electromagnetic compatibility (EMC) protocols for their purposes. They have also set up facilities for related testing and certification. Most EMI problems can be solved by following standard electrical and electronic engineering principles and practices. Shielding, Grounding, Filtering, Transient Suppression and Surge Protection are some of the standard EMI control techniques. What about general public and environment? How to take care of their health related concerns and problems? How to save other living things and biological systems? Perhaps, lessons learned from the CNG introduction in Delhi, should help preparation of guide lines and drafting of laws for EMR control. In other countries, one standard way is to issue Declaration of Conformity, certifying that the concerned equipment will not cause harmful EMI or EMR to others, and will function satisfactorily in normal electromagnetic environment. Cell Phone Towers Since there are no laws in India to control EMR from things like cell phone towers, a PIL has been filed by an NGO, praying for suitable directions to all concerned. A committee has also been appointed by the Govt. of India to go into details of the issues and to draft laws and guide lines. In the recent times, overwhelming increase in the number of mobile phones and the number of service providers competing with each other, have created such a situation that we see cell phone towers every where; even on residential buildings, schools, hostels and hospitals. These towers are radiating high power radio waves, continuously exposing children, senior citizens and people needing health care to harmful electromagnetic radiations. These towers should be located away from residential and other such vulnerable areas and should use minimum essential radio power. Several operators could share towers, saving on space, rentals and costs. Vulnerability from EMR Most vulnerable are children, women during pregnancy, sick people, senior citizens, ATC (air traffic control) staff, radar operators, radio station staff, electrical power station staff, etc. Most vulnerable locations are hospitals, particularly ICUs, maternity homes, schools and nurseries; residential buildings, particularly sleeping areas; hotels and guest houses, old age homes, etc. Biological Effects Common biological effects are headache and Migraines; eye irritations and Cataracts; loss of appetite; fatigue and exhaustion; giddiness or dizziness; vomiting sensation; loss of temper and fluctuation in BP; altered concentration and memory loss; anxiety and depression; sleep disruption or Insomnia; reduced REM sleep altered EEG (brain wave), etc. Serious Biological Effects are brain tumors, Alzheimer s disease, Parkinson s disease, eye cancer, Epilepsy, Leukemia, stomach pain and digestive disorders; destabilization of the Lymphatic system; disturbances in the nervous system; interruption in the maintenance of hormones; brainwave disturbances in alpha, theta and delta wave signal patterns. Dr Soma Sarkar and the group from DIPAS have studied the effect of radiofrequency electromagnetic field on human DNA of army jawans (radar or radio operators), who worked 2 hrs daily, in the morning, for 1 month on radar working at GHz, 115 W, near field power density of 1.3 W/m2 at 10 m; and radio sets working at MHz, mw. They isolated DNA from 5 ml blood and used 5 µg DNA for digestion with different restriction enzymes. The study indicated DNA modulation in the lymphocytes of radar and radio operators exposed to radiofrequency electromagnetic fields. Prof Paulraj and Behari from JNU have reported low intensity microwave radiation effect on developing rat brain. Their study was on 30 days old Wistar Rats exposed 2 hrs/day, 6 days a week, for 35 days at 2.45 GHz (0.34 mw/cm 2 ) and at 9.9 GHz (0.125 mw/cm 2 ). They specially designed and used an anechoic chamber for this purpose. Study of brain tissue from the cranial cavity demonstrated affect on certain growth related enzymes. They observed significant decrease in PKC (protein kinase C) activity and significant increase in ODC (ornithine decarboxylase) activity. Earlier, the authors had also reported significant decrease in fertility in rats exposed to 200 MHz. Kaplan and group have reported biological and behavioral effects of prenatal and postnatal exposure to 2450 MHz electromagnetic radiation in the squirrel monkeys. Pregnant monkeys were exposed at second trimester 3 hr/day and 5 days per week and continued to be exposed for 6 months post-natally at 0.34 mw/g, and 3.4 mw/g. 3 of the 33 mothers died a few days after birth of fetuses and without any prior indication; 9 died during first few months after birth 2 of them were exposed only prenatally (at lowest exposure of 0.34 mw/g); 6 of the animals, that were exposed postnatally, also died (2 were from the 0.34 mw/g exposure limit group and 4 were from 3.4 mw/g group) In another study, blocking of Melatonin production by Hz EM Fields has been reported. Melatonin, basically a natural neurohormone helps healthy sleep, maintains body temperature reduces cholesterol, blood pressure, growth of breast cancer, and tendency for blood clots a scavenger of free radicals and is anti-cancerous. The study of 60 workers (exposed to power frequency fields) at a Finnish garment factory found melatonin levels on weekday nights less than on Sunday nights, when they were away from the factory. Tests at 12 mg or higher have demonstrated significant blocking of the inhibitory action of melatonin and Tamoxifen (a widely used anti cancerous medicine). Recently, several news papers and TV cannels have reported studies indicating EMR effects on sperm quality and damage to fertility of men. Natural Resonance Frequency of Human Beings RF energy is absorbed more efficiently at resonance. In adults, the resonance frequency is usually about 35 MHz, if the person is grounded, and about 70 MHz if insulated from ground. Different human body parts may be resonant from 30 to 3000 MHz. Adult head is resonant at around 400 MHz, while a baby's smaller head resonates near 700 MHz. Absorption is also dependent upon polarization. Microwave Oven Cooking Water molecules, being polar, develop torque when subjected to EM waves vibrate at 2.45 GHz and produce frictional heat, which is used for cooking. Because of leakages from door, particularly because of improper maintenance, and frequent openings to check cooking status, excessive EMR can propagate. This is specially dangerous for pregnant women; they should wear appropriate shielding aprons to protect themselves and the baby. Of course, there are views regarding harm done to food by microwave cooking; this should be seen in the light of the fact that cooking, in itself, may be considered unnatural, and may have some undesirable effects. There are reports about impaired & broken cells, which may make food easy pray for viruses and fungi; deformation of food molecules and creation of new synthetic compounds; conversion of amino acids and alkaloids in to carcinogens; decreased vitamin B, C, E and essential minerals. Specific Absorption Rate (SAR) for Mobile Phones SAR is a measure of the rate of energy absorbed by (or dissipated in) an incremental mass contained in a volume element of dielectric materials such as biological tissues. SAR is usually expressed in terms of watts per kilogram (W/kg) or milliwatts per gram (mw/g). Guidelines for human exposure to RF fields are based on SAR thresholds where adverse biological effects may occur. When the human body is exposed to an RF field, the SAR experienced is proportional to the square of the electric field strength induced in the body. Tests for SAR have to be conducted with mobile phone transmitting at the highest certified power. SAR limit recommended by ICNIRP (International Commission on Non- Ionizing Radiation Protection) is 2W/kg averaged over ten (10) gram of tissue. SAR limit recommended by IEEE (Institute of Electrical and Electronics Engineers) is 1.6W/kg averaged over one (1) gram of tissue. Other related reports are also available from Federal Communication Commission (FCC ), August 1996, USA; Radio Communications (Electromagnetic Radiation Human Exposure) Standard 1999, Australian Communications Authority (ACA), May 1999; Council Recommendation of 12 July 1999 on the limitation of exposure of the general public to electromagnetic fields, Official Journal of the European Communities, SAR ratings of about 0.5 W/kg (10g) are considered safe enough. Precautions for Cell Phone Use Precautionary approach has been recommended by WHO (Word Health Organization) in relation to the use cell phones and EMR protection, etc. While using cell phone, use speakerphone as much as possible; keep phone as far away from body as possible; use hands-free option, preferably with an air-tube; use ferrite beads on headset wires to filter RF; and limit use to the bare minimum and turn it off when not essential. Use of Bluetooth headset for hands-free operation can be worst than regular use; even though it uses very low power, its continuous or prolonged attachment to the ear can be unsafe. Concluding Remarks Electromagnetic waves are nature s gift to mankind. Its equitable and safe utilization is very important for the efficient sharing of the spectrum and health of all living things. It is essential that appropriate laws are enacted to protect this natural resource. The subject of radio spectrum utilization and electromagnetic pollution hazards has also been highlighted by the President India in his addresses on Dec 14, 2006 at New Delhi and Feb 23, 2007 at Chennai. References 1. Sandlas VP. Microwave and Millimeter Wave R & D in India. IETE Technical Review Golden Jubilee Special Issue on R & D in Electronics in India, Vol 20, Number 2, Mar- Apr Sandlas VP. Microwave and Millimeter Wave Developments in India', Vikram Sarabhai Memorial Lecture. Proceedings, IETE Symposium on Microwave and Millimeter Wave - Recent Trends, Dehradun, Sandlas VP. EMC Considerations for the Satellite Launch Vehicle SLV 3. Proceedings, All India Conference on Electromagnetic Interference and Compatibility. The Institution of Engineers, Calcutta, Sandlas VP. EMC in Aerospace Systems and Good Intra-system Design. Short-term course on EMI/EMC, IIT, Madras, Sandlas VP. Radio Frequency Interference or Electromagnetic Pollution. EDUSAT multicasting lecture, Vigyan Prasar, New Delhi, May 2, Soma Sarkar, et al. Effect of Radiofrequency Electromagnetic Field on Human DNA. DSJ, Vol. 56, No. 2, April pp Paulraj R, et al. Low Intensity Microwave Radiation Effect on Developing Rat Brain. Proceedings of National Conference: Microwave 2006, Jaipur 8. Kaplan J, et al. Biological and behavioral effects of prenatal and postnatal exposure to 2450-MHz electromagnetic radiation in the squirrel monkey. Radio Science, pp 135S-144S. 9. Abdul Kalam, Dr APJ, President of India. Connectivity for Billion People, Address at the Inauguration of 'India Telecom 2006 Mapping the Road Ahead, New Delhi, 14 Dec Abdul Kalam, Dr APJ, President of India. Research Enhances Global Competitiveness in Communications, Address at the Inauguration of International Conference on Signal Processing, Communications and Networking, Anna University, Chennai, 23 Feb Dhiraj Kumar Singh. Exposure Limits for Non-Ionizing Radiation. Proceedings, International Conference on Electromagnetic Interference and Compatibility (INCEMIC 2006), Society of EMC Engineers (India), Feb 23, 2006, Bangalore.
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