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
Above the Influence funding and oversight of Above the Influence ceased, and it transitioned to become a program of the not-for-profit Partnership for Drug-Free Kids. In 2006, the Government Accountability Office released the results of a five-year study, concluding that the previous "My Anti-Drug" campaign was ineffective, and likely counterproductive, leading those exposed to an increased perception that others use marijuana, stating, "analysis also indicated that among current, non-drug-using youth, exposure to the campaign had unfavorable effects on their anti-drug norms and perceptions of other youths’ use of marijuana — that is, greater exposure to the campaign was associated with weaker anti-drug norms