Various risk factors in industrial environments can affect hearing status and healthy in today’s modern society. Noise control and hearing conservation program is very crucial in preventing workers exposed to high levels of noise in the work places.In the current article we are going to discuss issues such as industrial noise control, noise characteristics and standards and techniques for noise control. Then the methods for individual hearing conservation and medical care will be described in details.

Objectives: we were aimed at studying the difference in the effect of noise and pure tone on the residual inhibition in patients suffering tinnitus.
Method: patients were selected among whom referred to audiology clinic in Ran faculty of rehabilitation sciences and aged between 20-70 years old. Our method in studying patients was experimental- masking with pure tone was performed in patients who had experienced partial residual inhibition with noise.
Results the differences between the masking methods was not statistically significant.
Conclusion: it seems that no significant differences exist between the two mentioned methods in masking tinnitus.

Today, sound is one of the detrimental factors in the workplace and its harmful impact has been so important that scientists have named it "Noise Pollutions".Hearing is one of the five senses of human being which is also a medium for communicating with other s and enjoying the pleasant feeling of listening to a piece of music. In spite of this, changes in the intensity and frequency of sound can make it annoying. Using Sound Level Meter to measure the dB of noise in the workplace and noise control principles will be discussed here.

Exposure to noise is a one of the common problems in any industrial places. Many solutions have been introduced to overcome the deleterious effects of noise pollution maintaining and repairing systems in the equipments, environmental control and hearing conservation systems are some of these solutions that could be mentioned.
There are various types of Hearing protection devices and each one is useful under special circumstances. Commonly, different Hearing protection devices have a particular brochure to introduce information about the manufacturers and the quality of noise reduction in that special production.
Three different methods are commonly used to determine the noise reduction factor in various Hearing protection devices. All these methods have been presented based on the mathematical evaluations and according to the spectral features of the sound existing in the environment and then the sound pressure level is determined in dBA. In the current article we will have a look on the mentioned arithmetic models and their special characteristics.

There are some insufficiencies in the Hearing Conservation Program that are exponentially exacerbated by lack of the standard and observation for this program and little interest in team work activities. Regarding the noise measurement instruments, limitation in the measurement lack of the equipments and also incomplete evaluation are clearly detected.The performed investigations have demonstrated that most of the industrial centers have no baseline auditory curve and sometimes do not intend in hearing screening evaluations. that is mainly because of the need for sound protected environment and calibrated instruments and also 14 hours of sound rest before the experiment.Her the problems in performing hearing conservation program is discussed in more details.

Noise pollution is the problem of the industrial world that along with noised induced by traffic has become a problem in human life.This is more problematic in Tehran because of the traffic and the accumulation of small or large industries. People are profoundly exposed to the high level noises and there are increasing demands to solve the problem of noise in Tehran or at least alleviate it.In the current article we will have a brief and quick look to the noise making industries, the reason behind the noise pollution and the strategies for facing the disturbing industries.

Noise pollution is one of the major problems for the present time and it can affect the life of human being. Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life. Researchers have mentioned a lot of devastating effects of noise that can disrupt the physical and psychological health of human beings. Noise pollution has also been considered as an important issue which needs to be solved in industrial countries and also as a main factor that is required to be minimized in factory construction and also in producing machinery. In the current article we are aimed at discussing some solutions that natural environment can bring to mankind regarding the reduction of noise pollution.

Introduction: Several animal studies have been performed that demonstrates a relationship between the amount of magnesium ion in the plasma and the hearing thresholds following exposure to noise, Mg++ has been considered as an effective factor in  prevention of noise induced hearing loss in animals.The aim of this study was to discover whether Mg for a long period of time have a protective effect on occurrence of Noise Induce Hearing loss.
Method: The subjects were randomly chosen among individuals who were under training in army service for two months. The subjects were treated in a double-blind manner by placebo and magnesium ion. Threshold estimation and blood examination was performed for all subjects before and after treatment. All subjects were exposed to noise during 8 weeks training in the army.
Results: The statistical difference between two groups which was treated with placebo and magnesium ion was significant.
Discussion: This study is compatible with previous in vivo observations and animal studies demonstrating the protective effects of magnesium on noise-induced impairment of inner ear.

Industrialization has had many complications for human beings and has been a threat to social mental and physical health. Vibration induced noises in the workplace is one of the main devastating factor in producing hearing loss in workers.Recently, several investigations on the issue of noise pollution and noise dosimetry and also Noise induced hearing loss have been developed. In the current article we will have a look and sometimes reconsideration on the results and of these studies and will discuss the findings in regard to noise control and management in details.

The word of "Ergonomics "is composed of two separate parts: "Ergo" and" Nomos" and means the Human Factors Engineering. Indeed, Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. It has applied different sciences such as Anatomy and physiology, anthropometry, engineering, psychology, biophysics and biochemistry from different ergonomics purposes.Sound when is referred as noise pollution can affect such balance in human life. The industrial noise caused by factories, traffic jam, media, and modern human activity can affect the health of the society.Here we are aimed at discussing sound from an ergonomic point of view.

Technology has made people to be exposed to a lot of sources of noise because of the instruments they use at workplace or at home. Dentists are a group of such people who are especially subject to different sources of noise such as high-speed air-turbine headpieces, operated at 300,000 to 400,000 revolutions per minute In the current study we were aimed at measuring noise at the dentists&apos office estimating hearing thresholds in dentists and determining the reason of hearing loss and finally determining the role that work experience e play in the hearing loss occurred.Dentists have been divided into groups based on the work experience and subjects were randomly selected from the dentists of various groups. Sound levels were measured in clinical settings and in a pre-clinical laboratory for estimation of hearing-damage risk among dentists,The findings demonstrated that all dentists regardless of age and gender suffered a notched hearing loss at 6000 Hz. Additionally hearing loss was worse in right ear.Since sound energy of high-speed air-turbine headpieces is mostly concentrated in high frequencies, it can lead in the most possible hearing loss at 6000Hz.

Material and method: by using a dosimeter we tried to study the amount of noise exposure each worker is exposed to the microphone was connected to the collar of the shirts and the dosimeter to the belt. The audiometric evaluations were performed before starting work in the factory.
Results: the years of experience in the factory has a significant correlation with amount of hearing loss in the workers of the noisy environments (based on the findings of the dosimetric measurements)
Conclusion: the findings of the current study demonstrated that workers of the door and window construction factory were exposed to high level of noises and their hearing thresholds were largely affected by the noise pollution. This is in accordance with results of the similar studies. This impact was mostly revealed in the forgers.

Sound is an inseparable part of human life and provides us with lovely experiences such as listening to music. Musicians from classical orchestras to rock groups are exposed to high decibel of sounds. Musicians playing percussion musical instruments are exposed to high level of impact noise and players of Brass musical instruments are highly exposed to noise peaks higher than 100dB. Woodwind players are enduring the risk of posing directly in front of Brass players. Based on the above-mentioned risks for hearing loss clinical consideration of noise induced hearing loss in musicians is highly required.In the current study we were aimed at examining hearing stratus of classic and traditional musicians by means of pure tone audiometry in Islamic Republic of Iran Broadcasting. 33 subjects were evaluated aged between 22 to 59 years old. Their musical experience was variable between 6 to 45 years.The study demonstrated that most of the musicians in this study suffered bilateral high frequency hearing loss with a notch in the frequency range of 4-8 KHz.

Introduction: We estimated the noise in an industrial shoe factory to determine the effect of noise in the workplace on the hearing status of the workers in such environments.
Materials and method: the intensity of noise in dB in different parts of the factory was estimated. Then working people in each part was selected randomly and their hearing thresholds were evaluated by Conventional audiometry.
Results: The results demonstrated that 23% were required to estimate thresholds more precisely and 95 needed close examination by Otolaryngologist. Besides, 10% of the workers suffered sensory neural hearing loss whose 2% of them diagnosed as NIHL.
Discussion: Since the mentioned factory has good hearing conservation program for the workers, it seems that promoting the program can decline the number of noise induced hearing losses to the least numbers.

Background: workers in the spinning company were audiologically evaluated to estimate the impact of industrial noise of the factory on their hearing status.
Material & Method: subjects were 185 workers of the spinning post in the first flat of yarn. Hearing thresholds were compared at the beginning of their employment and after 1 to 19 years of work experience.
Results: the percent of hearing deficit was lower than the data reported by WHO.
Discussion: efficient application of hearing conservation devices has had a remarkable effect on hearing status of workers.

Background: Many Endogenic and exogenic factors can affect the individual&aposs susceptibility to noise exposure, for instance middle and outer ear characteristics, the amount of oxygen transmission, skin color, medical history, mental state and the patient&aposs attention, age, cigarette smoking and many otjher factors affect the amount of noise induced hearing loss and acoustic trauma.The current study was aimed at investigate the impact of various Endogenic and exogenic factors on the amount of PTS and TTS in veterans in Hamedan province.
Results: The results of the study manifested that:- Veterans with tinnitus suffered more hearing loss than patients without this symptom.- Extended intensity of noise and exposure time to war noises can exacerbate the amount of hearing loss in veterans who had fight more.- The degree of hearing loss in patients who had previously suffered middle ear infections or otitis or the familial history of hearing loss was more than people without such history
Discussion: The findings of our study in compatible with the results of other similar studies and confirms the effect of different pathologic and non-pathologic factors on the degree of noise induced hearing loss.

As the industry develops in the societies, human being is more likely to exposed to high level of noises and be at risk of hearing loss. Urbanism and working in the situation which are not in accordance with the personal nature make people even more susceptible to risk factors of hearing loss.   Exposure of workers to industrial noise has been the subject to several studies and it seems that reconsidering the situations in both society and nature can be a key to change environment for decreasing noise in the society.For example in Tehran, geographically, the slope of the earth from north to south is 5-10% which is a main factor contributing in noise pollution.Moreover, the source of most outdoor noise worldwide is mainly construction and transportation systems including motor vehicles, air craft noises and rail noises. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area.In the current article we have examined both conditions in the hearing condition of workers with high levels of noise exposure.

Workers in the Municipality of Tehran expose to high level of noises. The major sources of noise are the vehicles for garbage collection, Asphalt production and its usage in construction of pavements, Repairing motor vehicles, technical and constructive implementation including road and building construction , Forging, Concrete planning, Welding, Building structure and  etc.Although most of such activities are performed by Contractors, many workers are exposed to high levels of noise during such processes. Since hearing conservation program is a duty for the Municipality, we have managed to use some new protocols to prepare a convenient and quiet environment for workers that is going to be discussed here in the present article

Prescription of hearing aid is an extensive special category of knowledge in the field of audiology. This article is aimed at discussing the function of hearing aid and also management of patients in the noisy environments and presenting solutions to overcome problems regarding to this issue along with taking a look to the equipments prepared nowadays to cope with noisy situations.

We designed this study to measure the Percussion caused by pneumatic drill( 32gram) which is used commonly in different in city services. this study have been performed in the summer of 1375 in Hamedan. The results demonstrated that the average background noise level (including environment and compressor) was 92.4 with standard deviation of 5.4 dBC, the average background noise level of the drills while working was 109.6 dBC with the standard deviation of about 2.2dBC and the average peaking factor was 18.6 with a standard deviation of 3.7dBC. the average background noise level of the drills while working in a distance of 5m, 10m and 20m from the source respectively were 98.6 dBA(with a standard deviation of 2.8dBA), 91.5dBA(with a standard deviation of2.6dBA) and 86.8dBA with a standard deviation of 2.8dBA).Based on the obtained results and the potential effects of exposure to noise which mainly can be summarized to damage to auditory system, interference with the communication skills, neural excitation, Hypertension and tachycardia the side effects of noise should be taken in to account seriously.Based on the mounting evidences regarding the adverse impact of working in the noisy environment and the damaging consequences of living in such atmospheres and the findings of the current study which confirms that the noise exposure level is more than allowed limit, the health of the workers and citizens is threaded by the noise pollution factors mentioned in the current study and serious considerations should be taken in to account.