A. Background of the Study
Because their wheels clattered on paving stones, chariots in ancient Rome were banned from the streets at night to prevent the noise that disrupted sleep and caused annoyance to the citizens. Centuries later, some cities in Medieval Europe either banned horse drawn carriages and horses from the streets at night or covered the stone streets with straw to reduce noise and to ensure peaceful sleep for the residents.(Berglund & Lindval 2:1-195) In more recent times in Philadelphia, the framers of our Constitution covered nearby cobblestone streets with earth to prevent noise-induced interruptions in their important work. These examples pinpoint two major effects of noise from which men in all ages have sought relief: interruption of sleep and interference with work that requires concentration. It is interesting that noises emanating from the various types of roadways of today are still among the most important sources of environmental noise, even though the types of noise are not those that existed in Rome, Medieval Europe, or 18th century Philadelphia. Our modern roadways (including road, rail, and air) and the products of modern technology produce increasing levels of unwanted noise of varying types and intensities throughout the day and night that disturb sleep, concentration, and other functions.(Lee & Fleming ) This noise affects us without our being consciously aware of it. Unlike our eyes, which we can shut to exclude unwanted visual input, we cannot voluntarily shut our ears to exclude unwanted auditory input. Our hearing mechanisms are always “on” even when we are asleep.(Babisch 113:A14-15)
The noise problems of the past pale in significance when compared with those experienced by modern city dwellers; noise pollution continues to grow in extent, frequency, and severity as a result of population growth, urbanization, and technological developments. For example, within the European Common Market, 65% of the population is exposed to unhealthy levels of transportation noise.(Carlos 318:1686-1689) In New York City, maximum noise levels measured 106 dB on subway platforms and 112 dB inside subway cars. These levels have the potential of exceeding recommended exposure limits given sufficient duration of exposure.(Gershon et al. 83:802-812) In 1991, it was estimated that environmental noise increased by 10% in the decade of the 1980’s. ( Suter ) The 2000 United States Census found that 30% of Americans complained of noise and 11% found it to be bothersome. Among those who complained, noise was sufficiently bothersome to make nearly 40% want to change their place of residence.(U.S. Census Bureau, Housing and Economic Statistics Division.) That noise pollution continues to grow in scope, variety, and magnitude is unquestioned; it is only the extent of the growth that remains unknown.
In comparison to other pollutants, the control of environmental noise has been hampered by insufficient knowledge about its effects on humans and about dose-response relationships, but this seems to be changing as more research is carried out. However, it is clear that noise pollution is widespread and imposes long-term consequences on health.(Committee on Environmental Health, American Academy of Pediatrics) In 1971,
3a World Health Organization (WHO) working group concluded that noise is a major threat to human well-being. That assessment has not changed in the intervening 30-plus years; if anything, the threat has intensified.
The various sounds in our environment (excluding all those sounds that arise in the workplace) to which we are exposed can be viewed as being either necessary (desirable) or unnecessary (undesirable). One might consider the sounds produced in and around our homes by garbage disposals, dishwashers, clothes washers and dryers, refrigerators, furnaces, air-conditioners, yard...