Ultrasonic Sensors FAQQDo Murata ultrasonic sensors cause health problems? Do ultrasonic waves affect the health of the human body or animals (pets)? 

There are no laws that regulate the “sound volume” of aerial ultrasonic waves. As a general guideline, it is reported that long exposure to ultrasounds of 105-115dB or more may cause buzzing in the ear and discomfort. It is recommended that the ultrasonic volume be kept below the above limit in the sensor range used.