| French scholar, Gavreau, first reported the nature and biologic effect of infrasound in 1966. for the first time, whose frequency ranges from 0. 0001 to 20Hz There are all sorts of sound in the nature. Sound whose frequency ranges from 20 to 20, OOOHz is audible. Infrasound can' tbe heard. Over decades of years, with the development of industry, traffic, environment protection, and scientific technique, and under military requirement, the effects of infrasound on living things, especially human body have received great attention. Relative studies have been carried out in many countries. Part IInfrasound exists widely in nature, industrial production, traffic and transportation, and military environment. It has been important part of manufacturing noise and public noise, so it is significant to survey environment infrasound. In Russia, Japan, England and Australia, measurement of environment infrasound was ever performed. There 're few reports about overall measurement of environment infrasound in our country.We surveyed environment infrasound by using "convenient intelligence analyzing system to test low infrequency signal outdoors" which is manufactured by aerospace industrial head office and rehabilitation and physical department of Xijing hospital. This system consisted of signal perceiving transformation part, signal wave filtration and magnification part, signal collection and analysis part.There were four groups: bus group, train group, subway station group and seashore group. Data were collected for 30 seconds from every site in each group and 15 data were chosen randomly from each group to calculate mean value. Statistical analysis was performed by using SPLM application software, provideded by statistical department of the 4th Military Medical University. Results were expressed as X + S and t-test was used to determine if the difference was significant.We found that: the infrasound frequency in running bus (speed 90Km/h) was about 16Hz, and intensity was about HOdB. The frequency was significantly different between experimental group (speed 90Km/h) and control group (speed 40-50Km/h), (p<0.05), but intensity was not. The infrasound frequency in carriage was about THz, and intensity was about 98dB while the train was running. The difference of frequency was significant between experimental group and control group (p<0.05), and intensity were more significant (p<0.01). In subway station without subway locomotive passing, the intensity of low frequency noise also was rather high, 80.733 ?.824. In subway station with subway locomotive passing, the intensity was 81.933+3.674. The difference was significant (p<0.05). And the difference in frequency was significant too (pO.Ol). The results at Dalian seashore showed that when wave was striking (the height difference between waves was about 30-50cm visualized by naked eyes), the main frequency was 4Hz, intensity was 69.450 ?4.536dB; while sea was comparatively calm, the main frequency was 4Hz too, intensity was 66.200 ?3.488HZ.Taking all reports about infrasound together, we assumed that, with industrialization progress in the world, the tendency that proportion of low frequency noise, including infrasound, in work and life environment, increases, is more and more obvious. Infrasound, as a special physical factor, exerts great effects on body, which deserves close attention and further studies.Part nScholars all over the world reported that influence of infrasound on cortex, hippocampus and mutual action between other structures in CNS played important roles in obvious physiological changes following exposure to infrasound. In our study, BALB/C mice were exposed 2h per day to infrasound of 16Hz, 90dB and 130dB. After 1,7,14,21 and 28 days , the changes of Bcl-2mRNAx P53mRNA. IL-6, EL-6mRNA and GFAP in hippocampus of mice we observed by using immunohistochemistry and hybridization in situ. For the first time, we reported some biologica...
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