Ultrasound independent Advisory Group on Non-ionising Radiation (AGNIR) produced a report in 2010, which was published by the UK Health Protection Agency (HPA). This report 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). Ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz (20,000
Radio in the Republic of Ireland commercially in Ireland, and the first attempt to license such since 2002; as well as what will amount to four stations easily receivable in most of Dublin city and county. It is expected these may be the last commercial analogue services to be licensed, as the FM band will be highly saturated in Dublin and the midlands of Ireland. Digital Radio Mondiale (DRM) on Ireland's many unused ITU-allocated medium wave frequencies is expected to be the next round of licensing, particularly as some of these allocations are 15 to 20 kHz wide, which is enough for FM-alike quality with the