Community-based infrasound investigation

Abstract

Infrasound is not only associated with wind turbines and volcanoes. Low levels of disturbing infrasound that can have long term adverse impact on residents are also associated with sources such as bridges, transportation, barges, mechanical equipment and entertainment sound systems. This paper describes measurements to identify potential infrasound sources impacting a residence in a Mississippi River town in Minnesota. Initial monitoring was performed in a second floor room over a 24 h period with five samples up to 30 min using an Apollo sound analyzer. Supplemented with sound level meter readings, an average peak at 12.5 Hz appears to be associated with a nearby river crossing bridge. Peaks at this frequency peaks can not be attributed to room dimensions. Subsequent readings were taken in several rooms and outside with a micro-barometer system. These data supported earlier readings but showed differences between rooms and indoor and outdoor spectra. Unfortunately there are no standards or guidelines for indoor infrasound levels and only limited solutions for addressing these community infrasound sources. Whether or how infrasound could be incorporated into community noise ordinances that could possibly prevent adverse residential exposure to infrasound will be discussed.