Survey on Effect of EMF Emitted by CRT Computer Monitors in Bangladesh

As the world is being industrialized and technological revolution continues, there has been an unprecedented increase in the number and diversity of electromagnetic sources. While all these devices have made our lives richer, comfortable and easier, they have been accompanied by concerned possible health risks due to their electromagnetic field (EMF) emission. Electro-Magnetic Fields commonly known as Non Ionizing Radiation is emitted from high power transmission lines, computer monitor/video display unit, radio waves of different frequencies (extremely low frequency to microwaves), telecommunication, satellite, radar etc. which causes health hazards to living system and environment. CRT monitors are still being used in various computer composing shops, photocopy machine shops. Their EMF health effects have not been studied in Bangladesh. The data were collected from various places in Dhaka, Bangladesh: Banani Super Market, Mohakhali, Farmgate Green Road, Nilkhet and Uttara. Both Electric and Magnetic fields were measured for CRT monitors. These results showed that in many cases the magnetic field radiated from the different sources are greater than the threshold limit.


Introduction
It is obvious that electricity is the main tool for the advancement of modern civilization. At the same time, we are also informed about the adverse effects of varying degrees of Electro-Magnetic Fields (EMF) commonly known as non-ionizing radiation (NIR) which do not ionize the media like that of ionizing radiation (i.e. α, β and γ, etc.) It is reported that high power transmission lines [1] [2], computer monitor/video display unit, radio waves of different frequencies in (extremely low frequency to microwaves) telecommunication, satellite, radar etc. also cause harm to living systems [3] [4], especially in human beings for example. It is known that high power transmission lines cause human health hazards rather than a common electrocution. Even there are evidences that the cause of clinical depression and commitment of suicide are related with the emission from the power lines [5] [6]. A significant percentage of miscarriage is recorded among women using electric blankets, electrically heated waterbeds and video display unit or computer monitor. There are instances that occupational hazards like risk of developing Acute Myeloid Leukemia (AML) may occur among the people working in the field of telecommunication. Cancerous thyroid tumor, suppression of T-lymphocyte cell etc. are also found to occur among the persons exposed to non-ionizing radiation. Nancy Wertheimer was the first scientist responsible for identifying the association between magnetic fields and childhood leukemia [7].
At the same time lower animals are reported to very much sensitive to electromagnetic fields. It is observed that animals like rats make their living brooding holes away from the high electric field and bees block-up their hives in the chronic presence of NIR/EMF. As a consequence, scientists and health physicians in developed countries have become aware of the effects of NIR [8]. Their research and observations have brought out some remarkable results linking low level alternating electromagnetic fields with serious health hazards. The 50 Hz and 60 Hz power lines fields (low frequency), pulsed radar systems and high power Extremely High Frequency (EHF) communication systems are genuine concerns for mankind.
It is suspected that the cause of Sudden Infant Death Syndrome (SIDS) may have some relation with EMF. There is also evidence that biological effect like immune deficiency, sensitive lymphocytes, disrupting DNA, cellular breakdown is being affected by NIR.
It is also known that several hundred kilometers of high power transmission lines (National Power Grid) run through the villages, fields and residential areas of Bangladesh. The length of these is extending day by day to meet the increasing power demand even in the rural areas. Besides several radio, 150 Survey on Effect of EMF Emitted by CRT Computer Monitors in Bangladesh television transmission and relay stations are radiating radio waves continuously. The numbers of these stations are bound to increase in the near future.
Bangladesh has many ground satellite stations and more will be installed soon for the commercial broadcasting of television programs. These will receive and transmit high frequency, high power radio waves in Giga Hertz range. Uses of PC's are increasing rapidly in offices, industries, research laboratories, banks and commercial houses even in schools, colleges and universities in our country. Use of mobile/cellular phones which uses very high frequency radio waves (800 MHz -2100 MHz) are also increasing worldwide. The total number of Mobile Phone subscriptions has reached 121.860 million at the end of January 2015 [9]. Considering these facts, it can be assumed that we are always exposed to non-ionizing radiation in our daily life mainly from artificial sources like radar, satellite, telecommunication, radio and television transmissions, microwave communications, high voltage power lines etc.
Much research has been performed in this regard. Most recently, Epidemiological survey of people working in EMF field exposed to high frequency have been investigated [10]. Also, research was performed for epidemiological survey on effect of EMF emitted by photocopy machines generally used in Dhaka city Bangladesh [11]. Survey was done on EMF emitted by Lab equipments in various labs of Southeast University in Bangladesh for possible health hazards [12]. A case study was done on EMF near high voltage transmission line [13]. Also, a review was done on Non Ionizing Radiation (NIR), its harmful effects especially from Mobile/Cell Phone and Towers [14] Non-ionizing radiation (NIR) from a varying Electromagnetic Field (EMF) not only causes health hazards but also causes various problems or disturbances in electronic equipments. These problems or disturbance caused by EMF is called interference, commonly known as Electro-Magnetic Interference (EMI). The EMI may be defined as unintentional generation of either radiated or conducted energy that interferes with the normal operation of other electronic equipment or system. Scientists and engineers from all over the world are very much concerned about it and trying their best to overcome or at least to minimize the problem.

Materials and Methods
A magnetic Science International MF meter (Serial No 624335) was used for measuring the magnetic field values for the various CRT monitors. A Cughill Field Mouse for Biohazard Awareness was used for measuring the threshold values for both electric field and magnetic field around the machines. This Cughill Field Mouse instrument was designed by Dr. Roger Coghill of UK. The students visited physically at various locations and filled the prescribed form for the CRT monitors.

Epidemiological Survey
Findings at different EMF sources: All the readings were taken from various parts of Dhaka, Bangladesh. In Table 1, epidemiological survey data were collected from the Banani Super Market Dhaka from 3 CRT monitor operating shops. Reading number 4 was taken from Digital Logic Design Lab (DLD lab), A.R. Tower, Southeast University, Banani, Dhaka. All these data were taken on 12.12.2013. The operators were asked questions form questionnaire forms regarding their age, working years, number of hours working per day, smoker/non-smoker, various symptoms of their health and other comments. He is NOT aware of any health effects due to EMF. He is fit compared his age.
In Table 2, epidemiological survey data were collected from Uttara Dhaka from 10 CRT monitor operating shops. The operators were asked questions form questionnaire forms regarding their age, working years, number of hours working per day, smoker/non-smoker, various symptoms of their health and other comments. In Table 3, epidemiological survey data were collected from Nilkhet Dhaka from 17 CRT monitor operating shops. The operators were asked questions form questionnaire forms regarding their age, working years, number of hours working per day, smoker/non-smoker, various symptoms of their health and other comments.

EMF Measurements
In Table 4, EMF readings 1-3 were taken from Banani Super Market. The readings of 4.1-4.8 were taken from DLD (Digital Logic Design) labs, A.R. Tower, Southeast University, Banani, Dhaka. These data were taken on 12.12.2013. A table was completed with the following information: PC company name, model number and the following data were taken using the Coghill mouse: Threshold distance in front of the screen measured from the centre of the screen cm, threshold distance at 45 o angle from the normal drawing at the centre in cm, threshold distance at the top of the monitor in cm. The maximum magnetic field was measured using the MF meter. Observations if any were also noted.  In Table 5, EMF readings were taken from Uttara. Of the 10 readings, serial number 1 was taken on 8-3-2014, reading numbers 2-4 were taken on 9-3-2014, and readings 5-10 were taken on 22-7-2013. Similar to table 4, all the same parameters were noted and measured for EMF reading.

Discussions
From epidemiological studies given in tables 1-3 it has been found that common diseases from among the workers are indigestion, vomit, insomnia, pain in hands and legs, stomach ache, mental depression, skin disease, cataract, sexual problems, hairs turning white etc. In many of the photocopier shops the operators were working in congested space with lots of machineries around. There are many devices and power lines around them, having a congested environment and low circulation of air. Most of these CRT monitor operators are not aware of any adverse health effects due to its use. Some of the operators are smokers and have been for a couple of years, which might have had some negative effects on their health.
From the EMF measurement studies given in tables 4-6, it was found from the results that the magnetic field values are much higher than the threshold level. Because of the nature of the wiring both in the ceiling and floor, all the rooms had higher magnetic field than threshold value. There were many electrical machines in the shop at a small distance, so did not get magnetic field threshold values. Most of the places under study were dingy, and in most cases lots of electrical devices placed in the shops, some near the switchboards. Operators work on an average of 10-13 hours a day in those shops. We have in mind to include other regions for the study to continue. In rural areas in Bangladesh, these CRT monitor shops still prevails due to less expensive purchase of CRT PC monitors.
EMF measurement studies given in tables 7-10, these monitors were taken from as early as year 2002. In table 7, some of the threshold distances are must higher. In table 8, it is seen that only within 10 days time, the KOBIAN monitor has a higher magnetic field reading increasing to 143.4 mG with starting at only 0.8 mG when powered on. In tables 9 and 10, the FLATRON PC monitors and LG Studioworks monitors show higher magnetic field values at the back of the instrument. These data indicates that at that period, the CRT monitors were extensively used but most of the models have now become obsolete or not being used anymore.
A potential hazard to health can be produced either as a result of the exposure of the human body to NIR, or by interaction with technical devices, which are themselves affected by NIR and they give rise to health hazards (e.g. interference with electro medical devices, unintentional triggering of electrically activated detonator and ignition of flammable materials). This is especially true if the individuals concerned are not aware of the potential hazard to be unable to identify it.

Conclusions
From the above lab results, it has been found that in most cases the magnetic field has crossed threshold value. The electric field also has a higher threshold value in some of the equipemnts. Also, the magnetic field maximum exposure was nearly 200 mG in many cases. Wiring must be done according to the building code 2012.It is hoped that this survey will be helpful as a preventive measure for photocopier operators who might get affected tomorrow. Same kind of experimental data on epidemiological survey can be done in other parts of Bangladesh. There are couple of factors for occurrence of these illnesses, amongst them excessive smoking, exposure to radioactive elements, fire hazards etc. NIR may be one of the factors for causing or enhancing these illnesses. It might have direct or indirect effect for affecting the overall health issues. Although it cannot be said that NIR is the direct cause for the illnesses, rigorous studies needs to be carried out in order to arrive at this conclusion. For this further works in broad area and time periods are required.
In order to get rid of the health hazards caused by all those systems, people should be aware of them and accordingly precautionary measures should be taken. It is necessary to be acquainted with the harmful effects of non-ionizing radiations on living systems and also on the environment that we are living in and to find appropriate corrective measures for minimizing or controlling the hazards of NIR as far as practicable. Also, the power consumption of a CRT monitor is more than 10 times than a LED or LCD monitor. The general public should be educated regarding the harmful effects of CRT monitors and replace them by LED/LCD ones, which are becoming much cheaper nowadays even in Bangladesh within the financial capabilities of general public. That's why many typing/editing shops in Dhaka city which are now well off have replaced their CRT monitors with LED/LCD monitors. It is to be noted that LED/LCD monitors also take less space in the shop, which is a win-win situation.
Since magnetic field is more harmful than electric field, there must be a limit both in the residential and occupational levels between 0.2 to 0.3 µT or 2.5 mG. (This value is internationally recognized as standard limit in many countries). However, for the staff working at very high frequency transmitting stations, safe precautions such as wearing of special clothing, screened helmets and secured goggles should be taken. The duration of exposure must be kept to the minimum possible. It must be ensured that intensity of radiation in the body does not exceed the recommended maximum level (10 mW/cm 2 , 195V/m in U.S.A. and 0.1 mW/cm 2 , 20 V/m in CIS).