Environmental Engineering Reference
In-Depth Information
variety of emotional responses. Learned helplessness may also explain why too few
of them complain despite the growing numbers of community residents who are dis-
turbed by noise [6]. Without a fuller understanding of the psychological factors to
predict annoyance across communities, Staples [34] believes that government agen-
cies, e.g., FAA, are unable to set standards to protect community groups affected by
surrounding noises.
Low frequency noise, though not necessarily loud, e.g., the music coming from a
downstairs bar, a passing boom car, an entertainment center; nearby ventilation and
air conditioning units; industrial machinery, or vehicles whose mufflers no longer
muffle, are especially annoying to people living in urban environments [3, 35].
These lower frequency sounds, below 200 Hz, are often accompanied by vibrations.
Individuals begin to hear their doors or windows rattle or feel some movement in
their beds. Annoyance to low frequency noises are exacerbated by these accom-
panying vibrations [36]. Leventhal [35] noted that regulatory agencies generally
measure noise levels on the A weighted dB scale, which is not sensitive to low fre-
quency sounds; he concludes that the contribution of low frequency noise is ignored
because of the way sound is measured.
4.5 Effects of Noise on Physical Health and Well-Being
The human ear responds directly to sound and sound that is too loud, as discussed
earlier, can damage the ear resulting in a loss of hearing. However, unwanted sound
can affect other organs and systems in the body in an indirect way. Sound, which is
not necessarily loud, e.g., footsteps of upstairs neighbor or a dripping faucet, may
still be deemed bothersome because it is unwanted sound. The body responds to
unwanted, uncontrollable, and in some cases unpredictable noise through a complex
set of physiological changes typically identified as stress or arousal. The various
adverse health effects of noise, many of which are stress induced, has recently
been reviewed [36]. Stress leads to an outpouring of so-called stress hormones
(epinephrine, norepinephrine, and cortisol). These hormones produce an increase
in blood pressure, an increase in heart rate, an increase in respiratory rate, and a
slowing of digestive activity. A single stressful noise exposure is followed by a
return of these hormones to baseline levels. However, with repeated stressful noise
exposures, there may not be time for all the various affected systems to return to
normal or baseline levels. Thus, repeated exposure to noise can bring about long-
lasting physiological changes in the cardiovascular system and other systems. We
can safely say that noise, like other forms of stress, can adversely affect physical
health.
The Office of Noise Abatement and Control (ONAC) in the EPA recognized noise
as a health issue when it published its 1978 document
Noise: A Health Problem
[5].
This document stated that noise may contribute to heart and circulatory disease even
though more studies were called for to validate the link between noise and heart and
circulatory ailments. The document concluded that there was enough information
