There's been some work in the past to show a correlation between power lines and cancer which has been questioned. However, the research is heavily funded by the Department of Energy and the Electric Power Research Institute, an industrial research organization.
Infrasound has been an interest for weapon designers:
[QUOTE author=http://crab.wordpress.com/2008/01/14/a-short-history-of-sound-weapons-pt2-infrasound/]Infrasound is low frequency audio beneath the human range of hearing. Infrasound constantly surrounds us, generated naturally; wind, waves, earthquakes and by man; building activity, traffic, air conditioners and so-on. Low frequency sound is used by marine mammals to communicate over vast distances and by birds to determine migration patterns.
At higher volumes infrasound of around 7-20hz can directly affect the human central nervous system causing disorientation, anxiety, panic, bowel spasms, nausea, vomiting and eventually unconsciousness (supposedly 7-8hz is the most effective being the same frequency as the average brain alpha wave). The effect is unintentionally (or not?) generated by the extreme low frequencies in church pipe organ music, instilling religous feelings and causing sensations of “extreme sense sorrow, coldness, anxiety, and even shivers down the spine.”(1) in the unsuspecting congregation. Low frequency sound generated naturally or by building work and traffic is said to be the cause of reported apparitions and hauntings (2) – blamed on the ghostly 19hz frequency which matches the resonating frequency of the human eyeball:
Frequency & effects:
7 Hz: Supposedly the most dangerous frequency corresponding with the median alpha-rhythm frequencies of the brain. It has also been alleged that this is the resonant frequency of the body’s organs therefore organ rupture and even death can occur at prolonged exposure.
1-10hz: “Intellectual activity is first inhibited, blocked, and then destroyed. As the amplitude is increased, several disconcerting responses have been noted. These responses begin a complete neurological interference. The action of the medulla is physiologically blocked, its autonomic functions cease.” (Gavreau )
43-73hz: ” lack of visual acuity, IQ scores fall to 77% of normal, distortion of spatial orientation, poor muscular coordination, loss of equilibrium, slurred speech, and blackout”.(Gavreau )
50-100hz: “intolerable sensations in the chest and thoracic region can be produced – even with the ears protected. Other physiological changes that can occur include chest all vibration and some respiratory rhythm changes in human subjects, together with hypopharyngeal fullness (gagging). The frequency range between 50 and 100 Hz also produces mild nausea and giddiness at levels of 150 – 155 dB, at which point subjective tolerance is reached. At 150 to 155 dB (0.63 to 1.1 kPA), respiration-related effects include substernal discomfort, coughing, severe substernal pressure, choking respiration, and hypopharyngeal discomfort.” (Davies)
100hz – At this level, a person experiences irritation, “mild nausea, giddiness, skin flushing, and body tingling.” Following this, a person undergoes “vertigo, anxiety, extreme fatigue, throat pressure, and respiratory dysfunction.”(Gavreau )
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Light strobing has neurological effects, seizures for one. It is claimed that modern techniques for mind control combines it with color modulation.
Excessive sound has pathological effects.