| With the rapid development of mobile communication technology,the way ofpeople's life got much better than before,however,the living circumstanceshas been affected inevitably to the different extent at the same time for theelectromagnetic radiation caused by communication device. The harm fromelectromagnetic radiation includes the heat effect,no-heat effect andcumulation effect. The electromagnetic radiation of mobile communicationstation is mainly from the electromagnetic leakage of the transmitter and thesignal emission of the antenna.The transmitters are generally set up in thetransmitter building ,and the intensity of transmitter radiation is much lower.The antenna of mobile communication station is put up on the 15 to 50 metreshigh tower or masion.But the power transmitted by the antenna is solimited,and it is gotten from the parallel electromagnetic waves,not the uprightwaves from which people under the buildings will suffer from the lowerradiation than state standard.These days the electromagnetic radiation hasbeing increased in our country,and there are more10,000 devices used byindustry and science research and medical treatment.In a few of yearsago,the increasing user had reached the number of 60,000,000 untill inJune,2000 with the development of mobile communication devices, thestations of mobile communication having more than 70,000.The 《The rules of electromagnetic radiation protection》(GB8702-88)was setdown by the State Environment Protection Bureau in 1998,meanwihle, 《Thesanitation standard of surrounding electromagnetic waves 》(GB9175-88)waspublished by the State Healthy Ministry.Since then the State EnvironmentProtection Bureau also established a series of the rules including 《Theinstrument and the method of electromagnetic radiation surveyed 》(HJ/T10.2-1996),《The method of the effection of electromagnetic radiationand the standard》(HJ/T10.2-1996) etc.During these years,the mobile communication has developped fast in ourcountry, it becomes the most mobile phone user 's country in the world,so themobile communication stations have set up everywhere in the cities.Butpeople feel more nervous about these stations so that many complaintsincreased year after year.Apparently,the construction of mobilecommunication stations have affected the social stabilization and peopleliving.So it is necessary and urgent for us to know aboout the affection of theelectromagnetic radiation from mobile communication station.The purpose in this paper is to research a kind of the situation ofelectromagnetic radiation pollution and its surrounding affection of BaiShancity according to the results of the electromagnetic radiation measured aroundthe mobile communication station in BaiShan city. This result will be applied tocontrol the electromagnetic radiation pollution of BaiShan area for improvingthe electromagnetic surrounding quality and protecting people's safety.Themain content includes the surrounding investigation of BaiShan city, theinvestigation and measure of the original electromagnetic radiation, theprediction and calculation of mobile communication net radiation ,and theactual results of mobile communication net radiation.The radiant point inBaiShan city came from the TV station as well as the broadcast station beforethe mobile communication net setting up.First all, test area would be set offthe many of small area,then the 42 points in th four main streets of city wouldbe disposed. The measuring instrument is a HP8591A frequency analyst thatmeasures every point by the different frequencies surveying way.Whilemeasuring the different frequencies the stable higher 35dB frequency wouldbe taken as the final data.The frequency analyst displays DB measuring thefield intensity,compared with the state standard,so DB has to be convertedinto V/m,then we would get the integrated field intensity.The most highestresult of field intensity at every point is 0.0348V/m,and it is far lower than the12V/m standard result of public irradiation dosage, 《 The rules ofelectromagnetism protection》(GB8702-88). The emission power of mobilecommunication station is 25w .According to the rule of electromagnetismprotection,value method and standard of electromagnetic radiation(HJ/T10.3-1996),we should take the each station as the center with 500 metrerange. The results of the electromagnetic radiation from the each mobilecommunication station plus the most highest original electromagneticradiation of 0.0348V/m in formulas would get the forecast results.As the resultof calculation,after the run of mobile communication station,the field intensitywas 8.991V/m at a10-metre distance to the antenna.That result was a little bitmore higher than the standard of 5.4V/m,the result of 《The rules ofelectromagnetic radiation protection》,and safety standard of 《The sanitationstandard of surrounding electromagnetic waves 》.The field intensity that was4.496v/m at a 20-metre distance would fit the standard,and it 's lower than thesafety standard of 《The sanitation standard of surrounding electromagneticwaves 》 .At a 500-metres distance, the field intensity decreased by0.1798V/m.Therefore,concerning a single station area,the intensities ofelectromagnetic radiation caused by the stations meet the requirement of thestandard outside the 20 –metre radius.For the area of many of centralizedstations,the intensities of electromagnetic radiation had increased a little bitmore than the single station. Its intensity inside 100-metre radius rangeincreased less because the radiation intensity of the close distance waspowerful when they were added together.At the range of 100-300 metreradius,the radiation intensity of many of the stations would be addedmore,and it would be from 0.3V/m to 0.9V/m,lower than the standard result of5.4V/m,which also meets the standard requirement of 《The sanitationstandard of surrounding electromagnetic waves 》 (GB9175-88).Accordingly,the safety distance between the buildings around the mobilecommunication stations and the antennae has to be 30 metres.The powerdensity at this distance only accounts for 6% of the public result of 《The rulesof electromagnetic radiation protection》,and also meets the requriement of《 The sanitation standard of surrounding electromagnetic waves 》(GB9175-88). People like infant, pregnant woman,the elder and the sick etc,under this circumstance, living and working here for a long time has notsuffered from any danger affection.In conclusion,the most highest integratedfield intensity in the actual situation of 4.02V/m and the average integratedfield intensity of 1.46V/m that are far lower than the state standard of 12V/mmeet the requirement of environment protection. |
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