Because infrasound and ultrasound are difficult to hear, they do not cause noise nuisance in the ordinary sense of this word. Yet they can cause physical complaints such as pain, nausea, dizzy spells, pressure in the ears. Read here more concerning nuisance from infrasound and ultrasound and guidelines concerned, as well as ultrasonic products for the consumer.
While reading, you may come across technical words you do not know. Then, by all means, take a look at the page “Explanation of technical terms concerning sound”.