• Annoyance of infrasounds

At the present developed procedures of evaluation of annoyance of low frequency noise (LFN) on human and occupational health are based on international standards, ISO 7196 and ISO 9612. These standards are based on levels of thresholds of the human auditory system and subjective observations of vibrations of human body impacted by infrasound waves. In 1998 the first limits of exposure to infrasound and low frequency sounds were introduced to the guidelines of the American Conference of Governmental Industrial Hygienists (1999). Recent discoveries resulted significant sensitivity of the central nervous system on infrasonic waves especially below 10 Hz and the observed follow‐up effects in the brain. New obtained results showed the impact of LFN on the electrical potentials in the brain accordingly to pressure of waves on the human body. Signals recorded in industrial workplaces were used for further studies with typical LFN spectra with 5 Hz in chamber at laboratory. External noise, electromagnetic fields, temperature, dust and other elements were controlled. Results show that follow‐up effect is observed for 70% of the population. Multi‐channel system of acquisition of signals was used for sound pressure levels, EEG‐potentials, blood pressure monitoring, temperature, and pulse. Laboratory test included 45 volunteers of healthy people.