Ultrasound at train stations, stadiums and other public places can be a serious health risk. So say experts from the University of Souhampton. They proved that there is a group of people, susceptible to ultrasound. Usually the noise source is a loudspeaker, public address system and door sensors.
Scientists have detected ultrasound using a special app on your phone. The information gathered they have handled and correlated with the well-being of the people who were at that time under the influence of inaudible noise. Receptive personality complained about the confusion, the emergence of health problems not only among themselves but also their children. This writes NDTV.
In humans, susceptible to ultrasound, the organ of hearing has some peculiarities: he perceives louder frequency of 20 kilohertz. The result is a barely audible noise becomes for the person in an Intrusive ultrasound, the source of which is very difficult to establish.