Building acoustics and sick building syndrome.

The acoustic environment was examined in an office building with a high prevalence of symptoms typical of the sick building syndrome (SBS). Levels of ventilation noise exceeded 70 dB in many rooms. The peak was often found in the region below 20 Hz, which is the infrasound region and generally regarded as inaudible at these levels. Symptoms attributed to exposure to low frequencies include nausea, headache, choking, coughing, visual blurring and fatigue, which appear to overlap with some of the symptoms of SBS. Reducing fan speeds provided reductions in noise levels mainly in the audible region. Closing windows and doors to the rooms gave more effective reductions, but interfered with working routines.