Noise, is a combination of many different frequencies and different intensities of cluttered sound. Noise hazards have become one of the major occupational hazards in the world today, the harm of noise to humans is multifaceted, the damage to the auditory organs is the most obvious. Whether exposed to a brief strong pulse of noise or long-term repeated noise exposure caused by hearing loss, collectively referred to as noise hearing damage, also known as noise deafness. Noise deafness is common in people who work in noisy environments, such as naval turbines, tank drivers, airport ground crews, people who work under industrial noise in textile factories, and people who often wear headphones to listen to Walkman music and frequent karaoke rooms and disco halls! The degree of hearing damage is related to many factors such as exposure to noise time, noise intensity and nature. The mechanism of noise deafness is not clear, but there are several possible mechanisms: 1) mechanical damage theory; 2) microcirculatory disorders theory; 3) metabolic loss theory. There is no effective treatment for noise-induced deafness, so prevention should be the main focus. How to prevent the occurrence of noise deafness and reduce the degree of auditory damage has become an important issue of concern and research for scholars from various countries. I. Causes of noise deafness When noise exceeds 85-90dB, it causes damage to the cochlea, and the degree of damage is related to the following factors: 1. 2.Noise spectrum characteristics: Under the same conditions of intensity, high-frequency noise is more damaging to hearing than low-frequency; narrow-band noise or pure tone is more damaging to hearing than broad-band noise. 3, the type of noise: impulse noise is more harmful than steady-state noise. 4, exposure time and mode: continuous contact than intermittent contact damage; the longer the period of exposure to noise hearing damage is more serious; the closer to the noise source, the more likely hearing damage. 5.Individual susceptibility: Elderly and weak people, people who have suffered from sensorineural deafness, are susceptible to noise damage; while there are divergent views on the effects of middle ear diseases, some think that noise damage is relatively light in people with tympanic membrane perforation and interrupted auditory bone chain. The clinical manifestations of noise deafness 1.Progressive hearing loss: When you start to be exposed to noise, your hearing is slightly dull, if you leave the noise, your hearing will recover after a few minutes, this phenomenon is called auditory adaptation. If in the persistent, strong noise effect, hearing is obviously dull, after several hours hearing to recover, this phenomenon is called auditory fatigue. If further noise stimulation, it will lead to hearing damage, which is not easy to recover on its own. Generally, the curves of both ears are symmetrical, and those who are asymmetrical have other ear diseases or individual special conditions. 2. Tinnitus: It may appear earlier than deafness, or develop at the same time with deafness, and is high pitched, often annoying day and night. 3. Systemic reaction: headache, dizziness, insomnia, fatigue, memory loss, slow reaction, depression, palpitation, elevated blood pressure, nausea, loss of appetite, indigestion, etc. may occur. Third, how to do a good job in the prevention and treatment of noise deafness and health education of ship personnel First, strengthen the education of knowledge related to noise deafness. Let more people know the hazards and causes of noise deafness, and master the methods to control noise and prevent noise deafness. Secondly, the national noise health standards should be strictly observed in work and life, and the “Regulations of the People’s Republic of China on Prevention and Control of Environmental Noise Pollution” was published on September 26, 1989, which provides legal and technical guarantee for the management of noise and prevention of noise deafness. Regulations stipulate: 8 hours of work noise tolerance standard is 85dB (A), if temporarily can not reach the appropriate relaxation, but shall not exceed 90dB (A). Noise exposure time of less than 8 hours, that is, the contact time is halved, the noise may be allowed to increase by 3dB, but shall not exceed 115dB (A). Third, the most active and fundamental method to prevent noise deafness is noise control. To achieve the national noise health standards, so that the noise is reduced to the safe limit (85 ~ 90dB (A)), we must take appropriate measures to improve the engine room machinery and technical operations, such as the installation of anechoic, sound insulation, sound absorption and anti-vibration facilities in the engine room. Fourth, do a good job of personal protection, usually try to stay away from strong noise, such as must be exposed to noise of 90dB SPL (sound pressure level) or more, should use ear protection. Ear protection is an economical and effective measure for individual noise protection. According to their working principle, ear protectors can be divided into two categories: active and passive; according to the structure, they can be divided into four categories: ear plugs, earmuffs, anti-sound caps and communication headsets. The average sound insulation value of earplugs in the frequency range of 250Hz~8000Hz is 20~25 dB, and the good performance can reach 25~30 dB. The noise reduction of traditional earmuffs mainly relies on the sound insulation effect of earmuffs, which is ideal for the medium and high frequencies, but the noise reduction effect is poor for the low frequency band. The active anti-noise earmuffs introduced in the 1980s applied the active noise control technology to the traditional earmuffs, using the active sound from the headphones to offset the residual low-frequency noise in the earmuffs, thus making up for the shortcomings of the traditional earmuffs in terms of insufficient noise reduction in the low-frequency band, so that the earmuffs get uniform noise reduction effect in all frequency bands. Anti-noise helmet is the whole head cover protective gear, generally by the helmet shell, inner liner, earmuffs and other components, often in the helmet to introduce communication systems, and therefore complex structure, large and bulky, wearing uncomfortable, inconvenient to use, but because it has a very high sound insulation, high-frequency sound insulation value of up to 40 ~ 50 dB, not only to prevent air-conducted noise, but also attenuate bone-conducted noise to the inner ear, while It can prevent head impact. When there is no professional protective gear, even if the outer ear canal is stuffed with cotton, it can also play a certain role in preventing sound. A short break in the daily working hours in a noisy environment can reduce the noise damage to the hearing. The ship’s personnel should try not to use any Walkman and MP3 or CD, because the sound intensity is at least 85 to 87 dB SPL, and people will unconsciously increase the volume of the Walkman in a noisy environment, and the sound intensity will be even higher. Fifth, hearing examinations should be done regularly for workers in noisy environments for early detection. The main symptom of noise-induced deafness is progressive hearing loss, which can be accompanied by tinnitus. The early pure tone hearing curve is characterized by a “V”-shaped cut at 4000 Hz, and as the lesion progresses, hearing decreases to different degrees at each frequency. The early hearing loss is at 4000Hz, while the main frequency of people’s speech is 500-2000Hz, so the impact of speech communication is not significant and is only found during the hearing examination. That’s why it is necessary to have annual hearing check for living and working in noisy environment. Strive for early detection and early treatment to avoid further hearing loss. Individuals have different sensitivity, and it is best to adjust the working environment for those who are sensitive to noise. Application of vasodilators, nerve nutrients, antioxidants and drugs to promote cellular metabolism may be helpful in preventing and treating noise-related deafness. Sixth, drug prevention and treatment: At present, the main types of drugs for prevention and treatment of noise-related deafness are: drugs to improve microcirculation, including carbogen (which is a mixture of 95% oxygen and 5% carbon dioxide), corticosteroids, ATP, sodium nitroprusside, low molecular dextran, ginkgo biloba preparations, Chuanxiong, Salvia, and ginseng; drugs to promote neurotrophic metabolism, including neurotrophic factor, vitamin Seventh, hyperbaric oxygen therapy: Hyperbaric oxygen therapy can rapidly improve the oxygen supply to the inner ear, correct the cochlea’s hypoxic state, avoid hypoxic damage to the cochlea, and facilitate the recovery of the cochlea’s function; in addition, hyperbaric oxygen can improve the oxygen supply to the vertebral artery, thus increasing the blood and oxygen supply to the auditory artery of the inner ear, effectively In addition, hyperbaric oxygen can improve the oxygen supply to the vertebral artery, thus increasing the oxygen supply to the auditory artery of the inner ear and effectively changing the hypoxic state of the auditory system. Eighth, noise hearing damage susceptibility screening: In recent years, domestic and foreign research on noise hearing damage susceptibility has become a new hot spot in noise protection research. Population studies have shown that noise auditory damage is mainly proportional to the amount of noise exposure, the greater the intensity, the longer the exposure time, the more severe the hearing loss. Many studies have also shown that there are great individual differences in noise auditory damage, the same noise exposure, some individuals quickly develop noise auditory damage, or even noise deafness, while another part of the individuals have considerable tolerance, screening out these susceptible individuals, can be used as a criterion when the ship’s personnel are selected, so as to fundamentally achieve the protection of such people. In conclusion, the prevention of noise-induced deafness focuses on strengthening the propaganda of related knowledge, teaching to raise people’s awareness, strictly abiding by the national noise hygiene standards, strengthening personal protection, and conducting regular hearing examinations.