Safety
Professor Tim Leighton from the Institute of Sound and Vibration Research, University of Southampton, United Kingdom produced an 83 page paper entitled "What is Ultrasound" which was published in 2007. In the paper Leighton expressed concern about the growth in commercial products which exploit the discomforting effects of in-air ultrasound (to pests for whom it is within their audible frequency range, or to humans for whom it is not, but who can experience unpleasant subjective effects and, potentially, shifts in the hearing threshold). Leighton claims that commercial products are often advertised with cited levels which cannot be critically accepted due to lack of accepted measurement standards for ultrasound in air, and little understanding of the mechanism by which they may represent a hazard.
The UK's independent Advisory Group on Non-ionising Radiation (AGNIR) produced a 180 page report on the health effects of human exposure to ultrasound and infrasound in 2010. The UK Health Protection Agency (HPA) published their report, which recommended an exposure limit for the general public to airborne ultrasound sound pressure levels (SPL) of 70 dB (at 20 kHz), and 100 dB (at 25 kHz and above).
Read more about this topic: Electronic Pest Control
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