Lab _2 - Sound Revised 2-9-2011

Lab _2 - Sound Revised 2-9-2011 - Revised February 2011...

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Revised February 2011 Page 1 of 6 2/9/2011 EXERCISE #2 MONITORING NOISE LEVELS The most common sources of excessive noise include the construction industry, transportation, airport runways, and urban areas, among others. Excessive noise is an environmental pollutant. It may seem strange to categorize noise as pollution like we would with smog or chemical spills, but if we consider polluted air or impure water as pollution because it harms our health, then loud noise that is damaging to our hearing would fall into the same category! Certain extremely loud noises are obviously bad for our ears and the instinctive response is to cover them. However, some noises are not painfully loud, and although we may consider them harmless, over time these can lead to permanent damage. According to the U.S. Environmental Protection Agency (EPA) in their "Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety," a 24-hour exposure level of 70 decibels is the maximum level of environmental noise that will prevent any measurable hearing loss over a lifetime. EPA also identifies maximum noise levels of 55 decibels outdoors and 45 decibels indoors as necessary to prevent activity interference and annoyance. The physical energy released on the hair cells in the ear by continuous day after day exposure to noise leads to irreversible damage to these hair cells, causing hearing loss. Thus, it is important to recognize in our environment, this noise pollution that can cause long-term damage to our health. Hearing is the interpretation by your brain of the intensity of sound waves. The sensation of loudness is related to the intensity of the sound waves and is measured in units of decibels (dB).
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This note was uploaded on 03/24/2011 for the course ENGR 0845 taught by Professor Markjohnson during the Spring '11 term at Temple.

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Lab _2 - Sound Revised 2-9-2011 - Revised February 2011...

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