1988, China promulgated the national standard GB 8702-88 "electromagnetic radiation protection regulations". The applicable frequency range of the protection limit in this regulation is 100kHz~300GHz, which is the upper limit of the protection limit. According to the design requirements, "it is strictly forbidden to build new residential houses, schools and hospitals in noise-sensitive structures within 30 meters on both sides of the railway; In areas 30 meters away from the center line of the outer rail of the railway and within 200 meters, noise-sensitive structures such as schools, hospitals, nursing homes and concentrated residential areas shall not be built. "