Date Thesis Awarded

4-2018

Document Type

Honors Thesis

Degree Name

Bachelors of Science (BS)

Department

Biology

Advisor

John Swaddle

Committee Members

Matthias Leu

Randolph Chambers

Abstract

Noise is a pervasive pollutant with documented exposure consequences such as elevated stress, decreased survival, and decreased reproductive success for a variety of organisms. Most studies addressing the effects of noise pollution on organisms have focused on noise within the range of human hearing (20 Hz to 20 kHz). Ultrasound noise (≥ 20 kHz) is high frequency noise above the range of human hearing. Although inaudible, intense (high dB, high frequency) ultrasound has been documented in industrial settings with workers suffering from symptoms such as fatigue, nausea, and vertigo. In addition, intense ultrasound can cause decreased cell proliferation and altered animal development in some systems. Preliminary studies have suggested that ultrasound noise may be present in human occupied spaces outside of industrial settings with the public suffering from unintended exposure. In this study, we performed the first systematic survey of ultrasound noise outside of an industrial setting. Specifically, we determined the frequency range, intensity (amplitude), and sources of terrestrial ultrasound noise pollution in human occupied spaces on a U.S. university campus (William & Mary, Williamsburg, Virginia) to assess the degree to which people are chronically exposed to ultrasound. Our results indicate that on the William & Mary campus, ultrasound noise exists between 20 to 55 kHz and at an intensity between 13 to 78 dB SPL. In addition, we identified motion sensors as the primary source of ultrasound noise. Based on student use of surveyed campus spaces, we concluded that William & Mary students are chronically exposed to ultrasound noise pollution and are potentially suffering from the symptoms associated with industrial ultrasound exposure. The prevalence of motion sensors in public spaces outside the William & Mary campus suggests that ultrasound noise pollution may be ubiquitous.

Available for download on Monday, May 03, 2021

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