The Effect of Noise on Human Non-Hearing System

Many people now believe that noise causes diseases such as the cardiovascular system and the digestive system that are caused by uncontrollable noise emissions, which means that noise directly harms and damages the functions of these systems. Take daily exposure to strong noise, for example, if the noise level is in the 90-105dBA range, the sound intensity is still relatively small. Compared to the general use of ultrasound for human examinations, the sound intensity is small. With the mismatch between the air sound and the impedance of human skin, the sound energy that directly affects the organs in the human body is even smaller. This is different from the effect of noise on the human ear. Workers who have been exposed to 90-105dB(A) noise for a long period of time have severe hearing loss, and such damage is often not restored.
We believe that the impact of noise on the non-auditory system is largely caused by the emotional fluctuations caused by the sound and is an indirect effect. Then measures to protect hearing are also effective for non-auditory systems. Workers wearing ear protectors, such as ear plugs or ear muffs, can reduce the noise sensitization of the incoming central nervous system. This is a good way to kill two birds with one stone. Ordinary plastic earplugs can reduce the noise of 1000-8000Hz by 20 decibels (average), foam-type earplugs can be reduced by about 30 decibels (average), and the earmuffs have a slightly larger effect. Thus, the ear canal of textile workers is only exposed to noises below 75-90 dBA, and the incidence of cardiovascular and other systems is bound to be greatly reduced. The cost of such textile workers is extremely limited compared with the noise reduction of machines, and it is more realistic.
Therefore, to make noise protection, ear protectors are particularly important. However, due to the size of the human ear canal, if the ear canal cannot seal the ear canal, the noise reduction effect will be greatly reduced (at least a difference of 10 dB). Ordinary plastic ear plugs have this problem. Although it is also possible to produce large, medium, and small models to suit different ear canals, it is difficult to fit all people at the end and it is not easy to keep it closed. Foam ear plugs can overcome this disadvantage because it can naturally expand after being worn. The earmuff-type ear protector can utilize the elasticity of the shell edge and apply a certain pressure on the earmuff using the top bow that clamps the head, so that the edge is tightly attached to the cheek skin and the entire ear shell is covered. With particularly strong noise, it can also be used with earplugs, and its noise reduction effect can reach more than 45dB (average over the range of 1000-8000Hz). However, it is inconvenient for those who wear helmets and glasses, and the cost is much higher than that of earplugs.

It is often reported that the various ear protectors currently on the market are uncomfortable to wear, especially ear muffs, and workers are reluctant to use them. This is a specific issue to be considered in the promotion and application, but it cannot shake or relax the development, improvement and production of ear protection. We should use the ear protectors as a mandatory labor protection measure under strong noise, in order to effectively do a good job of workers' health protection work.