Noise indused hearing loss Control ppt presentation

Noise – Induced Hearing Loss (NIHL) : 

Noise – Induced Hearing Loss (NIHL) Every day we experience sound in our environment such as sounds from television and radio, house hold appliances and traffic. Normally we hear these sounds at safe levels that do not affect our hearing. When exposed to harmful noise i.e. sounds that are too loud or, loud sounds that last a long time the sensitive structure in our inner ear can be damaged, causing Noise-Induced Hearing loss (NIHL), these sensitive structures, called hair cells, are small sensory cells that convert sound energy into electrical signals that travel to the brain once damaged, our hair cells can not grow back.

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WHAT SOUNDS CAUSE NIHL ? This can be caused by a one time exposure to an intense “Impulse” sound viz Explosion or by continuous exposure to loud sounds on extended period of time, such as noise generated in a wood working shop. Sound is measured in units called Decibels on the decibel scale, an increase of 10 means the a sound is 10 times more intense or, powerful. Sounds of less than 75 decibels even after long exposure, are unlikely to cause hearing loss.

EFFECTS OF NIHL : 

EFFECTS OF NIHL Auditory Effects: a) Auditory fatigue:- Appears in 90 dB region and greatest at 4000Hz. May be associated with side effects such as whistling, buzzing, ringing or roaring sounds in the ears. b) Deafness :- In early stages victim is unaware of it. Hearing loss may be temporary or permanent

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- Temporary hearing loss results from specific exposure to noise. Occurs in frequency range of 4000 to 6000 Hz. - Permanent hearing loss repeated or continuous exposure to noise around 100 decibels. There may be partial or complete loss or destruction of the organs of corti. - When occurs due to occupation it is called occupational hearing loss. - Exposure to noise above 160 dB may rupture the Tympanic membrane and cause permanent loss of hearing.

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Non-Auditory Effects:- They can be: 1) Interference with speech Annoyance:- Is a psychological response. Neurotic people are more prone to noise then balanced people. Efficiency:- Where mental concentration is required them low level sound is required. Physiological Changes:- Many temporary physiological changes occur is body as a direct result of noise exposure. These can be: Rise in Blood pressure Rise in Intracranial pressure Increase in Heart Rate. Increase in breathing Rate

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Increase in breathing Rate Sweating General symptoms viz Nausea and fatique may also occur. Visual disturbance viz narrowing of pupils, reduced night vision. Economic losses:- Potential cost of noise induced hearing loss to industry is quite great.

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PREVENTION:- Control of noise source in Industries. Special areas must be earmarked. Protective green belts must be laid down between installation and residential areas Protection of exposed persons:- hearing protection is recommended for all workers who are constantly exposed to noise louder than 85 decibels in frequency bands above 150 Hz. Regular rotation of workers is expected in the workplace who are exposed to loud noise. Periodical audiogram check ups and use of ear plugs, ear muffs

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NIHL is a preventable hearing disorder that affects people of all ages and demographics. It primarily affects the working population. TWO TYPES OF NIHL:- NIHL caused by acoustic trauma. Gradually developing NIHL 1) NIHL by Acoustic trauma refers to permanent cochlear damage from one time exposure. 2) Gradually developing NIHL:- There is permanent cochlear damage from repeated exposure to loud sounds over a period of time. This can be caused by multiple exposures to musical concerts, nightclubs, loud noise in workplace etc. It is said that exposure to 90 dB(A) of noise for more then eight hours per day can result in permanent hearing loss.

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Controls of pollution:- The direct effect of air pollutants on plants, animals and soil can influence the structure and function of ecosystems affecting the quality of life. Source:- Automobiles – Major source Industries – They emit large amount of pollutants in to atmosphere petrochemical industries generate hydrogen fluioride, hydrochloric acid and organic halides some industries discharge carboimonoxide, Co2, Ozone, Hydrogen sulphide and sulphur dioxide and nitrogen oxides

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Domestic source:- combustions of coal wood or oil is a major source of smoke,dust, So2 and No2. Miscellaneous – Burning of refuse incinerators, pesticide, spraying, natural sources and nuclear energy programmes. All of these contribute to air pollution. Meteorological factors – Level of atmospheric pollution at any one time depends upon meteorological factors e.g. topography, air movement and climate. Winds help in the dispersal and dilution of the pollution

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Air Pollutants:- More than 100 substances which pollute air have been identified. Important ones are carbon monoxide, carbon Dioxide, Hydrogen sulphide, nitrogen oxide and fluorine compounds etc.Pollutions may be in the from of solids, liquids or gases. Combination of smoke fog is called smog. Monitoring of Air Pollution:- Best indicators of air pollutions are sulphur dioxide, smoke and suspended particles. There are monitored on daily basis at many sites. The result is collected by a central agency. Smoke or, soiling index:- known volume of air is filtered through white filter paper & stain is measured by Photo electric meter.

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Grit and dust measurement. Coefficient of haze – To know amount of smoke or other aerosol in air the regulatory approach to control Air pollutions differs from country to country as several sources. Of air pollutions having unique national component.

POLLUTION CONTROLS IN INDIA : 

POLLUTION CONTROLS IN INDIA The national Air Quality Monitoring programme sponsored by the central pollution control board (CPCB) since 1990 has generated database over last 14 years in 10 major Indian cities. viz Ahemedabad, Kanpur, Kochi, Chennai and Nagpur. The trend analysis showed that suspended particulate matter (SPM) exceeds the CPCB standard in all cities most of the time throughout the year.

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The concentration ration of <P10 fraction (human respirable particles) to the total SPM varies between 30 to 60% with coastal cities showing higher percentages. At Industrial sites the concentrations of human respirable suspended particulate matter is high Wet deposition of air pollution has also been evaluated by analysing rain water. First rain event has the maximum concentration of pollutants with low ph values and higher sulphate and nitrate contents.

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Protecting our environment does not have to put an end to economic programes. Free markets in permits to pollute, like free markets for other resources, can ensure that pollution is controlled at the lowest cost possible. WHO has recommended the following procedure for pollution control & prevention. a) Containment:- Prevention of toxic air substances into the ambient air. b) Replacement:- Replacing a technological process causing air pollution by a new process that does not. c) Dilution:- To the extent that it is within the self cleaning capacity of the environment. It has its own limitation.

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d) Legislation:- In many countries this is the control method i.e. clean Air Acts covering height of chimneys, research & educations. e) International Action:- WHO has established an international network of laboratories for the monitoring and study of air pollutions