Islamabad, October 08 (Online): Have you ever experienced nausea while waiting for your train? Or developed a sudden headache while out shopping? While there are likely numerous explanations for such occurrences, a new study suggests exposure to airborne ultrasound could be one.
The study suggested that the general public are unaware that they are being exposed to very high-frequency (VHF) sound and ultrasound (US) at levels over the current guidelines.
Such exposure could be putting people’s health at risk, a UK researcher claims, causing headache, nausea, dizziness, migraine and tinnitus – ringing in the ears. These are symptoms that have been reported in occupational settings among workers exposed to high sound frequencies through drilling, for example, or industrial cleaning devices.
However, study author Prof. Tim Leighton, of the University of Southampton in the UK, notes that such guidelines are only applicable to workplaces in which employees are aware of their ultrasound exposure, enabling them to protect themselves against any possible health implications.
“The guidelines are also based on an insufficient evidence base, most of which was collected over 40 years ago by researchers who considered it insufficient to finalize guidelines, but which produced preliminary guidelines,” notes Prof. Leighton.
“This warning of inadequacy was lost as regulatory bodies and organizations issued ‘new’ guidelines based on these early guidelines, and through such repetition, generated a false impression of consensus.”
Sound frequencies were recorded in a variety of public buildings in the UK, including train stations, libraries, museums, schools and sports stadiums – places where there had previously been reports of people experiencing symptoms that could be related to ultrasound exposure.
Prof. Leighton notes that there are a variety of ultrasound sources present in public places, including loudspeakers and door sensors.
The buildings assessed in the study were occupied by hundreds of people at the time of recording, he notes.
Data showed that the general public occupying the buildings were being exposed to VHF/US at levels over 20 kHz, which Prof. Leighton says has the potential to be a public health concern.
Prof. Leighton also calls for new guidelines that address the potential harms of ultrasound exposure among the general public.