Low-frequency noise refers to sound with a frequency below 200 Hz (octave). There are five main types of low-frequency noise sources in residential quarters: elevators, transformers, water pumps in high-rise buildings, central air conditioning (including cooling towers) and traffic noise. The sound that ordinary people can hear is between 20Hz and 20000Hz, below 20 Hz is infrasound, and above 20000 Hz is ultrasonic.
Hazards of low-frequency noise:
The direct impact of low-frequency noise on physiology is not as obvious as that of high-frequency noise, but it will have a long-term impact on human health.
1. Harm to pregnant women and fetuses:
Medical researchers at home and abroad have done a lot of research in this field, which proves that low-frequency noise will have many adverse consequences for pregnant women and fetuses. If you are disturbed by low-frequency noise for a long time, it is easy to cause neurosis such as neurasthenia, insomnia and headache, and even affect the fetus in the pregnant woman's abdomen, resulting in fetal malformation and so on. Living in such noise for a long time has a great influence on people's hearing and nervous system, which is an organic and irreversible change.
2. Impact on humans and animals:
Low-frequency noise has many effects on people's physiology and psychology. Psychological influence is mainly annoyance, and physiological influence is mainly intense infrasound stimulation, which can cause middle ear compression, earache, tympanic membrane injury, tinnitus, headache, nausea, vomiting, imbalance, blurred vision and so on.
3. Harm to human hearing and cardiovascular system:
Through the investigation of a thermal power plant, medical researchers learned about the impact of low-and medium-frequency noise exposure on the health of power producers. The results showed that the hearing loss of workers exposed to low-frequency noise of 0.5 ~ 6 kHz was significantly higher than that of the control group (P0.0 1), and the detection rate of high-frequency hearing loss and speech frequency hearing loss of workers exposed to noise was significantly higher than that of the control group (P0.0 1). The detection rate of neurasthenia syndrome, tinnitus and digestive system symptoms in noise exposure group was significantly higher than that in control group.
Low and medium frequency noise exposure is harmful to human auditory system, nervous system, cardiovascular system, digestive system and metabolic function.
4. Influence on blood sugar and blood lipid:
Low-frequency noise stimulation is introduced into cerebral cortex and hypothalamus through auditory pathway, which can affect the regulation of endocrine. The influence of noise on blood lipid is manifested by the increase of serum triglyceride and cholesterol content. People exposed to low-frequency noise have higher blood lipid and blood glucose levels.
5. Chronic damage caused by low-frequency noise:
Xuanwu hospital Otolaryngology Doctor of Medical University said that noise pollution has ranked first among the seven public hazards in the world. Low-frequency noise can directly reach people's ear bones, and make people nervous, tachycardia, hypertension and endocrine disorders. People are forced to accept this kind of noise, and they are easy to get upset, excited, fidgety and even lose their minds. If you are disturbed by low-frequency noise for a long time, it is easy to cause neurosis such as neurasthenia, insomnia and headache.
Through the above introduction, I believe everyone has a certain understanding of the harm of low-frequency noise. Attach importance to the protection of urban acoustic environment, strengthen all aspects of protective measures, protect women and children, protect urban residents, and protect the health of enterprise employees.