The experimental study was conducted under extensively controlled conditions on a former barracks site near Flensburg. A total of 44 persons were exposed to four different types of infrasound within approximately eight hours. Each sound exposure lasted 30 minutes. The physiological parameters heart rate, blood pressure, cortical activity and balance perception were measured both during and after the noise scenarios. irradiation. No statistically significant changes due to infrasound were found. Acute feelings of annoyance were assessed by means of questionnaires. The infrasound sounds were in the frequency range from 3 Hz to 18 Hz with sound pressure levels between 105 and 85 dB. The sounds thus represented a spectrum below, close to and just above the currently defined perception threshold. One of the noises was amplitude modulated. Amplitude modulations can occur, for example, in the emission of infrasound from wind turbines.
Stationary devices such as refrigerators, heat pumps and technical equipment e.g. wind turbines or biogas plants emit low-frequency sound including infrasound. Infrasound is defined as sound waves in the frequency range below 20 Hertz and is not perceptible to most people through hearing.
There is little scientific knowledge about the negative effects of infrasound below the threshold of perception. The UBA experimental study addresses this question. However, the study was conducted as an experimental study with a small number of test persons and a comparatively short exposure time to synthetic pure infrasound signals. Therefore, the research results cannot be generalized and no possible long-term health effects of infrasound immissions in the residential environment can be derived. In order to identify possible as yet unknown long-term effects, an epidemiological long-term study in the residential environment is required. UBA therefore intends to conduct a preparatory research project on this topic in the coming year.