What is EMF and EMR

What is EMF and EMR?

EMF - Electro Magnetic Field is an invisible charge of force that is associated with the use of electricity. Voltage in any wire creates an EMF around it. EMF is intangible - you cannot feel it, touch it, smell it or see it. EMF is present wherever electricity is used - all electrical appliances emit some EMF.

EMR - Electromagnetic Radiation is the transfer of energy by electromagnetic waves.

Electromagnetic waves are part of everyday life They are emitted by natural sources such as Sun and Earth All Objects emit electromagnetic emission because of their temperature called as thermal radiation. Man made sources of electromagnetic waves commonly used are electrical sources like washing machines, mixers, ovens, dryers, televisions, computers, broadcasting towers, radio waves (RF Waves) etc.

The Sun is the biggest source of Electromagnetic Waves in the atmosphere.Human beings also emit Electromagnetic waves Even Human beings emit electromagnetic waves. Thus if we were to take a problem from the legendary book on Physics by Resnik and Halliday (or any high school Physics Book using the Wiens Displacement Formula) and compute the wavelength emitted by human body at normal temperature of 34C (which is 307K) and identify the region in the electromagnetic spectrum, the answer would be 9.4m and in the Infra Red region. - Thus there is nothing to be afraid of electromagnetic waves

Electromagnetic Waves emitted by the Sun, Stars and Human Being

What devices emit EMF?

Any device that uses electricity emits some EMF - the questions are whether the amount of EMF it emits is within recommended limits.

Radio waves are also electromagnetic waves like those emitted by other sources shown ( TV, Computers, Microwave Ovens, Sun Light, FM Radio, Satellite TV, Police Wireless etc).

What are some sources of radiofrequency radiation?

RF EMR is produced by both natural and artificial sources. Natural sources like the sun, the earth and the ionosphere all emit low level RF fields. Artificial sources of RF EMR are mainly used for telecommunications purposes. Radio and television broadcasting, mobile phones, pagers, cordless phones, police and fire department radios, point-to-point links and satellite communications all produce RF EMR. Other sources of RF fields include microwave ovens, radar, industrial heaters and sealers, and various medical applications.

Manmade Sources of Electromagnetic Waves.

How is radiofrequency radiation measured?

RF EMR has both electric and magnetic field components. It is often convenient to express the strength of the RF field in terms of each component. For example, the unit "volts per meter" (V/m) is used to measure the electric field strength, and the unit "amperes per meter" (A/m) is used to express the magnetic field strength. Another common way to characterize an RF field is by means of the power density. Power density is defined as power per unit area and is expressed in units of watts per square metre (W/m2) (or milliwatts per square centimetre, mW/cm2, or microwatts per square centimetre, W/cm2). The quantity used to measure how much RF EMR is actually absorbed by the body is called the Specific Absorption Rate or SAR. The SAR is usually expressed in units of watts per kilogram (W/kg) or milliwatts per gram (mW/g).

Energy of the Photon

As we studied in our Class 12th Physics, all Electromagnetic Waves are constituted by an elementary particle called as the Photon. Wavelength and frequency determine the characteristic of Electromagnetic Field. Photons of higher frequency Electromagnetic Waves carry more energy than that of lower frequency field. As per Plancks equation the energy of a Photon (E) is proportional to the frequency.

E = hf

where "h" is called the Plancks Constant and f is the frequency

The above equation tells us that the Energy of the Photon of RF Waves is 6,00,000 times lower than the Energy of the Photon of Visible Light which is in the ratio of their frequencies. In other words as can be seen from Table below the Photon of RF Wave has energy which is 0.0000021 times that of Sun Light.Energy of Photons in eV and Comparison with Visible Light

RF wavesVisible Light/M2)X raysGamma Rays

Energy of Photon0.00000371.771,241124,070

Ratio wrt Visible Light0.0000021170070,012

The Electromagnetic Spectrum

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The electromagnetic spectrum extends from below the low frequencies used for modern radio communication to gamma radiation at the short-wavelength (high-frequency) end, thereby covering wavelengths from thousands of kilometers down to a fraction of the size of an atom. The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length.

Electromagnetic Spectrum is characterized by the frequency of the Electromagnetic wave. Thus the electric supply in our homes and offices is at 50 Hertz (50 Hz). The unit of frequency is the cycles per second that the Electromagnetic wave experiences and is named after the legendry physicist Heinrich Rudolf Hertz (22 February 1857 1 January 1894), a German physicist who first conclusively proved the existence of electromagnetic waves theorized by James Clerk Maxwell's electromagnetic theory of light.

Higher units of frequency are Kilo Hz (103), Mega Hz (106), Giga Hz (109), Tera Hz (1012), Penta Hz (1015) and Exa Hz (1018).We must mention here that FM 101 is actually FM radio at 101 MHz frequency.

Electromagnetic waves are divided into two categories - Ionizing and Non-Ionizing Radiations

Ionizing Radiations: Some electromagnetic waves carry so much energy that they have the ability to break bonds between molecules. These are called Ionizing Radiation. Examples include gamma rays given off by radioactive materials, cosmic rays and X-rays. Thus when we go to any hospital for an X-Ray or for CT Scan we find a sign board stating that CAUTION: X-Rays. This is because X-Rays are ionizing radiations.

Non-Ionizing Radiations: Electromagnetic waves that do not carry sufficient energy to break bonds between molecules are Non-Ionizing Radiations. All man made sources of EMF generally fall under non ionizing radiations. Also Non-Ionizing radiation are used safely in medical applications like MRI (Magnetic Resonance Imaging) and Sonography. Both MRI and Sonography use radio waves.

Use of Radio Waves in Medical Application

Sonography Machine

MRI Scan

Body Area Network (BAN)

Photoelectric Effect

One of the classical ways of explaining the Energy of Photon is to study the Photoelectric Effect. The photoelectric effect is the observation that many metals emit electrons when light shines upon them. Electrons emitted in this manner may be called photoelectrons.

The photons of a light beam have a characteristic energy proportional to the frequency of the light as discussed earlier. Albert Einstein showed that the Photoelectric Effect is possible only above a threshold frequency above which the Energy of the incident Photon is adequate to dislodge an electron (typically in the Ultraviolet band). If the photon energy is too low, the electron is unable to escape the material. Since an increase in the intensity of low-frequency light will only increase the number of low-energy photons sent over a given interval of time, this change in intensity will not create any single photon with enough energy to dislodge an electron. Thus, the energy of the emitted electrons does not depend on the intensity of the incoming light, but only on the energy (equivalently frequency) of the individual photons.

The Solar Cell uses the Photoelectric Effect to generate electric current.

This theory explained to the World as how important is the frequency of the Electromagnetic Wave since the Energy of its Photons depends on the same. The Radio Waves have frequency as 6,00,000 times lower than that of Light Waves and are thus incapable of producing any such effects which breaks a bond.

The above explains that even light waves are not able to break a bond below a threshold frequency and thus the RF Waves which have energy 600000 (Six Lakh) times lower than light waves are harmless.

EMF and Mobile Telephony

Mobile Telephony uses radio frequency (RF) signals to transmit and receive information by using extensive network of base stations. These Radio Frequency Signals are electromagnetic waves. The Base Stations are further classified as Macro Cells or Mobile Towers as they are commonly referred to and as Small Cells or Micro Cells or FEMTO Cells. Macro Cells are typically installed outdoors on rooftops or on ground based towers for wider geographical coverage and thus emit higher powers. Small Cells are typically installed indoors or outdoors for limited coverage and thus have lower power. The Electromagnetic Spectrum consists in order of increasing frequency the following - Low Frequency Waves, AM/FM Radio Waves, TV Broadcast, RF Waves used by Mobile Towers or Cell Sites, Satellite TV, Infra Red Waves, Visible Light, Ultraviolet Waves, X rays and Gamma Rays. Thus RF waves have even lower frequency than Visible Light and the effect of RF waves is a small subset of Visible Light (Sun Light).

Type of Towers used in Mobile Telephony

As discussed earlier, Mobile Telephony uses Radio Waves to transmit and receive information by using extensive network of Base Stations. The Base Stations are further classified as Macro Cells or Mobile Towers as they are commonly referred to and as Small Cells (In Building Solutions, Micro Cells, Femto Cells). While the former are typically installed Outdoors on roof top or on ground based tower for wider geographical coverage and thus emit higher power, the latter are typically installed Indoor or Outdoors at lower height for limited coverage and thus have lower power.

Two types of Tower are generally used in Mobile Telephony for Macro Cells as also depicted in photographs below Ground Based Tower Roof Top Tower

Ground Based Tower (GBT)Roof Top Tower (RTT)

EMF Standards and EMF ComplianceA standard is a general term incorporating both regulations and guidelines and can be defined as a set of specifications or rules to promote the safety of an individual or group of people. The ultimate goal of health-based EMF standards is to protect human health.>

A number of national and international organizations have formulated guidelines establishing limits for occupational and residential EMF exposure. The exposure limits for EMF fields developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).

Exposure, Emission and Measurement Standards

Exposure standards are basic standards of personal protection that generally refer to maximum levels to which whole or partial body exposure is permitted from any number of EMF emitting devices. Emission standards set various specifications for electrical devices and are generally based on engineering considerations, e.g. to minimize electromagnetic interference with other equipment and/or to optimize the efficiency of the device. Measurement standards describe how compliance with exposure or emission standards may be ensured.

Adoption of ICNIRP Guidelines for Telecom Sector in India

World Map showing the EMF Standards followed (India has stricter Standard than Europe)

"Most of the World Follows the ICNIRP Standards"

Most of the countries in world follow the ICNIRP (International Commission for Non Ionizing Radiation Protection) and FCC (Federal Communications Commission USA).

ICNIRP is the International Commission on Non-Ionizing Radiation Protection. It is a publicly funded body of independent scientific experts consisting of a main Commission of 14 members, its Scientific Expert Group and its Project Groups. The expertise is brought to bear on addressing the important issues of possible adverse effects on human health of exposure to non-ionising radiation.

In the year 2008, India has adopted ICNIRP guidelines, but consequently, to be on safer side India has revised the Guidelines and adopted further stringent guidelines (which are 1/10th of ICNIRP Guidelines, as detailed below) and were made effective from 01/09/2012 and was applicable throughout the Union of India.a. f /2000 W / m2 for the range 400 MHz to 2 GHzb. 1 W / m2 for the range 2 GHz to 300 GHz with f as frequency in MHz,

Thus for 900 MHz the EMF limit is 0.45 W/m2 for India. The above Standards are applicable for all areas of Public Access. For Occupational Areas of exposure for Technical Staff of Cellular Operator the limits are set as 50 times higher than those for Public Access.

Therefore, India has adopted one of the safest EMF safety standards in the world with emission levels more than 500 times lower than safe limits for its people across all age-groups.

The ICNIRP guidelines (and similar IEEE Guidelines) are endorsed by WHO (World Health Organization), are internationally recognized, globally accepted and widely endorsed. A comparison of the International Exposure Standards for RF field in various countries is USA, Canada and Japan as 12 W/m2 , ICNIRP and European Union recommendation as 4.5 W/ m2, Australia as 9 W/m2 and India as 0.45 W/m2 (highest value for 900 MHz Band).This makes them as ten times more stringent than 90% countries in the world.

It is mandatory for all the Telecom Operators across India to comply with these Guidelines. All the Compliance to the EMF standards is ascertained using the following methods a. Calculation Method based on ITU T recommendations.b. Software Simulations Method for electromagnetic mapping.c. Broadband Measurementsd. Narrow Band for Frequency Selective measurements

Exposure Zones - the area surrounding a Base Station can be divided into 3 categories Compliance Zone where EMF Signals are below the Standards of public access, Occupational Zone for Employees and Technicians of Cellular operator and the Exceedance Zone where the EMF Signals exceed the Safety Standard. All areas of Public Access must fall in the Compliance Zone.

Energy of the Sun

The Power Density received from the Sun is 1300 Watts / m2. It reduces to 1000 Watts / m2 when it reaches the Earth Surface.

Thus the EMF Standards are 2200 times lower than the Power Density received from the Sun (1000 / 0.45).

Let us see a case study done in Mumbai on a building wherein 4 operators were sharing a Cell Site.

The Energy received from the Sun in one hour has been compared with the RF Energy in 3 combinations- At 20 m from the Antenna In the Floor below the Roof Top housing the Antenna At 100 m away from the Antenna

With an average human life of 80 years, the life time RF exposure at just 20 m in line of sight from the antenna is equivalent to 40 hours in Sunlight, in the floor below as less than five hours in Sunlight and at 100 m is less than two hours of Sunlight.RF Waves Properties RF Waves are like Sun Light, they decay very rapidly with distance and have very low energy RF signals decay very rapidly with distance. RF signals are inversely proportional to square of the distance & frequency and at just 1 meter away from the antenna are one- thousandth (1/1000) of the power emitted by the antenna and the RF signals at 10 meters away from the antenna are one-hundredth of the signals at one meter from the antenna. The results shown are for 900 MHz for which the Standards have the lowest limit (f/2000) - thus if the same is achieved then the limit for higher frequencies would automatically be achieved By the time it reaches the street below or the next building at 10 metres away, it is more than 1,00,000 times lower than the original emission value. Thus if the EMF Standards are complied with in front of the Antenna then at 10 metres away the compliance is achieved by a further factor of 1,00,000 times. All of us have experienced that as we go indoors the RF signals become weaker and weaker. Distance1m2m4m8m16m

RF Signal Decay Factor0.0011/4 th1/16 th1/64 th 1/256 th

The decay of RF Waves with distance can be thus shown as under at 10 m it is 0.00001 times emitted power RF POWER DECAY FOR 900 MHz BAND WITH DISTANCE

Distance from antenna1m2m4m8m10m16m

RF Signal Decay Factor wrt emitted power0.0010.000250.00006250.0000160.000010.000004

Thus while the Standards are important, more critical is to assess the Power Density in actual areas of Public Access wherein it falls below thousands of times lower than the Standard. As per measurements on the street in front of the Cell Sites the Power Density is more than 1000 times lower than the EMF Standards and is in the range of W/m2POWER DENSITY MEASUREMENTS ON STREET JUST BELOW THE CELL SITE

Site NameLatLongAntenna Height above Street Level in mNumber of Operators at Cell SitePower Density Measured (W/m2)Ratio of EMF Standard With Measurements

Rachana19.218572.95623040.000391148

Kasam Tower19.186773.04613340.000371233

Honey Bee Hives on Mobile Towers

Photographs of Bee Hives on our towers and bird nests on our towers to dispel the myths being circulated that Radio Waves impact Bees

Photo1 - Site address: Gat no. 313/5,GTL GBT, Village Chinchpada, Tal Navapur, Dist Nandurbar, MH

Photo2 - Tower at Pen in Raigad District of Maharashtra

Photo3 - Chindwara in MP

The above photographs clarifies abundantly the myth being circulated that Radio Waves impact Bees.

Mobile Phones are Essential

From Good to have and bare necessity, the mobile phones have become an essential part of our life, they provide us connectivity in times of emergency. As the World moves towards the next generation of Mobile Phones i.e. 5G, we need to ensure that we keep pace and ensure that economic and social growth system continue of which the Mobile technology is now an inherent part.

Protection against EMF - Can I protect myself from EMF?

Radio Waves have been on Earth since the day it was created. The Sun, Planets and the Stars all emit Electromagnetic waves of different frequencies. What is important for us is to understand that whether these Electromagnetic waves are harmful and what protection mechanism has been built for human beings.

The ICNIRP Standards set limits for human exposure to RF EMR in the frequency range 3 kHz to 300 GHz. The Standards also include requirements for protection of the general public and the management of risk in occupational exposure, together with additional information on measurement and assessment of compliance. Safety is achieved in three ways.

Known Effects of RF Exposure

When biological tissue is exposed to sufficiently high levels of RF exposure, the tissue is heated and damage may occur. The ICNIRP Radiation Protection Standard "FOR LIMITING EXPOSURE TO TIMEVARYING ELECTRIC, MAGNETIC AND ELECTROMAGNETIC FIELDS (UP TO 300 GHZ)" is based on the well-established thermal effects of exposure to RF fields and is followed across the world. The exposure limits are set well below levels where any significant heating occurs. The Standard also sets limits for pulsed radiation that are intended to eliminate possible effects where heating is not evident (non-thermal effects). Thus even if we stand right in front of the Antenna we do not feel any heating effect.

Some research has indicated that non-thermal effects resulting from low-level RF exposure may also occur. However, the existence of these effects and their implications has not been sufficiently established to allow for them in the Standard.

It is most important to understand that the EMF standards limit the power emitted by Cellular Antennae. These standards are applicable even on the roof top where the Mobile Towers are mounted. Thus even the roof top has to be compliant to the standard for the RF Waves of all Operators added together. While we must know the EMF Standards, what actually matters is the signal strength at the point of measurement which is mostly thousands of times lower than the Standard.Safety Standards

Safety standards have been enforced for all types of Radiation (Ionizing as well as Non-Ionizing). As long as the radiation levels are within the safety standards there is nothing to fear. Again it is emphasized that Electromagnetic waves are a part of our lives ever since life started on the Earth.Wi-Fi Routers and Safety

The Radio Waves being used have very low energy and fall in the Non Ionizing Band (even Sun Light also falls in the same band with much higher frequency and much higher energy than radio waves). The Sun radiates most of its energy in the visible band and part of its energy in the Radio Band thus Radio waves are a part of nature and have been on earth ever since it was created. The Sun is the largest source of Electromagnetic Waves in the atmosphere. Even human being emit electromagnetic waves (mostly in the infra red band).

All electromagnetic waves are classified in two categories Non Ionizing Band when their energy is not sufficient to break a bond and Ionizing Band when their energy is sufficient to break a bond. In the Non Ionizing category fall the AM Radio, Police Wireless, Sonography, MRI Scan, FM radio, TV (Doordarshan), Mobile Radio & WiFi, Body Area Networks used by Doctors, Satellite TV, Infra Red, Sun Light etc and in the Ionizing Band are the X-Rays and Gamma Rays.

The Power of these radio waves decays very fast with distance at just one meter away it falls to less than ten-thousandth of its emitted value for a frequency of 2.4 GHz used by WiFi Radios and then decays further inversely as square of the distance. This makes the power as minuscule in areas of public access.

The maximum power emitted is limited by the EMF standards issued by FCC (Federal Communications Commission USA) and ICNIRP(International Commission on Non-Ionizing Radiation Protection) and are followed across the world including India.

In Case of WiFi the maximum emitted power varies between +10 dBm to + 20 dBm (Radio Waves use the unit as dBm which is deci-Bell with reference to 1 milli-Watt) which corresponds to the range of 10 milli-Watt to 100 milli-Watt (average 50 milli Watt). This further decays with distance as per point number 3 above. Thus by the time it reaches one meter away it is lesser by a factor of 10000 times and at two meters it is lesser by a factor of 40000 times lower than the emitted value.

The ICNIRP standards put a limit on emitted power density as 10 W / sq m as the safe limit for the band greater than 2 GHz in which the WiFi devices Operate. Also ICNIRP specifies that sources with Power Less than 2 Watt are classified as inherently compliant to safety Standards. In this case the emitted power is 50 milli watt which falls in the inherently compliant category. Thus the emitted powers are 200 times lower than the safe limit ( = 10 W / 50 milli watt) and at just one meter away are 2,000,000 times lower than the safe limit (as the power decays by 10000 times further).

Thus while the radio waves due their non ionizing band and extremely low energy are harmless with their emitted power itself being 200 times lower than Safe Limit and as an extra precaution a distance of one meter would achieve safety by a further factor of 10000 times.DoT Complaint Redressal System

DoT has rolled out a Public Grievance Number for Mumbai wherein complaints regarding EMF Radiation can be registered at 99 695 55000. DoT would then arrange a field visit at a prescribed fee of Rs. 4000/- in addition, the Field Units of DoT (TERM Cells) carry out monthly audits and there are strict penalties for non-compliance. Penalty of INR 10 Lakhs per Technology per location is levied in case any Cell site exceeds the Safety Norms.Thus RF waves energy is so low that strict adherence to these norms ensures there are no health hazards.The ICNIRP Standard has a built in safety factor of ensuring that RF Waves Power Density is 50 times lower than safe limit. In India this Safety Factor has been made 500 times in the Standards itself.

The RF energy from a Cell Site installed on a building doesnt radiate vertically down towards the top floor and instead radiates horizontally in front of the antenna and doesnt cause adverse health effects on the residents of the buildings where mobile tower set up is installed as is also confirmed by actual measurements.

Department of Telecom (DOT) has made it mandatory that even the rooftops housing the antennas are compliant to the norms.

The RF field weakens very quickly as it moves away from the antenna and its power is minuscule (very low) even as compared to Sun Light and reduces by 100,000 times by the time it reaches the street below or the next building.This ensures that RF Power Density is lower by Lakhs of times than the Safe Limit by the time it reaches the next building.

The Energy Received from standing in the Sun for One Hour is equivalent to that received at 20 mtrs from antenna for Two years.

During night time with reduced voice and data traffic, the emitted power is generally half of that during the day which is another salient feature built by default in all equipment.

With the safety aspect taken care of, there is absolutely no need for restricting the installation of towers & Cell sites on schools and hospitals as the current guidelines provide added safety margins for all sections of the population at all locations.

In times of emergency, all of us need the mobiles to communicate with our loved ones.Please always think of the analogy with the Sun the next time we come across such misleading information linking Mobile Towers to cancer. Also it is learnt that certain vested interests after creating fear in the minds of the public then market their so called anti radiation products. We need to guard against such activities.

Mobile Communications is a boon to the society and the world is making great strides in the same. India has adopted more stringent standards than even European Countries and strict compliance is being ensured for them as well.

Lastly, in the recent Uttaranchal floods with the help of telecom infrastructure, the stranded people could communicate and many lives were saved due to the same. Some time back about 6 boys lost their way in a National Wild Life Park, after many hours of struggle in this leopard infested jungle, one of the boys could get some signal on his mobile and all of them got saved. No helpline numbers for fire/ safety/ medical help can be reached in emergency if we do not have mobile coverage. No internet site can be reached as well.

This list is endless and goes on to say that from Luxury, to Good to have to Bare necessitymobile phones have become integral part of our lives, as both life support and life management tool and these would not work if cell towers are removed .v