| A typical high rise building in Beijing was chosen as a monitoring area for learning about the electromagnetic radiation level in high altitude environment.Wide band and narrow band monitoring instruments were used so as to estimate the general electromagnetic radiation environment level in monitoring area,and make clear of the sources from which the main electromagnetic energy was released as well.The results show that the general electric field intensity in this high altitude area is below the reference level for general public limited by national standard,though it is above the ground level.The monitoring area is mainly impacted by Medium wave Station,which is about 30 km away,and secondarily the Central TV Tower,which is about 9 km away.Medium wave signals from the frequency of 639 kHz have the biggest influence,taking up over 95% of the total energy in the frequency band of 100 kHz～300 MHz,and secondarily the medium wave signals from the frequency of 1.28 MHz.Some suggestions were also given based on the environmental protection perspective,such as,when sensitive buildings are constructed,the influence scope of medium wave should be taken into consideration because of its transmitting characteristics. |
