Ultrasonic humidifiers use sound vibrations at frequencies higher than can be heard by humans (> 20,000 Hz) to generate aerosolized water also have potential for inducing sonochemical reactions for chemicals present in water. This research focuses on examining oxidants formed within ultrasonic humidifiers, as well as the oxidants effects of contaminants in water used in the systems. Hydroxyl radicals were found using DMPO as a spin trap. Caffeine and 17β-estradiol, as pharmaceutical contaminants of drinking water, were both emitted from the humidifier when present in the water reservoir and would enter breathing air. Emitted 17β-estradiol was found at 60% of the initial concentration filled in the ultrasonic humidifier after 480 minutes. Caffeine exhibited less degradation than 17β-estradiol. Degradation of both pharmaceuticals was attributed to ultrasonic processes, most likely oxidation with hydroxyl radicals produced. Bromide as a contaminant of the fill water was found to remain constant over time. / MS / Ultrasonic humidifiers carry health benefits from humidified air, but also have potential for chemical reactions within the systems that can impact human health. This research focuses on examining oxidants formed in ultrasonic humidifiers, as well as the degradation of contaminants in water used in the ultrasonic humidifiers. Hydroxyl radicals were found to be generated within the humidifier system. Caffeine and 17β-estradiol, a common estrogen, are possible contaminants in drinking water, which may be used to fill a humidifier. Both were introduced and emitted from the ultrasonic humidifier. Emitted 17β-estradiol was found at 60% of the initial concentration filled in the ultrasonic humidifier at the start of 8 hours. Degradation of both pharmaceuticals was attributed to ultrasonic processes, most likely oxidation with hydroxyl radicals produced.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/95935 |
| Date | 12 June 2018 |
| Creators | Altizer, Chase Duncan |
| Contributors | Environmental Science and Engineering, Dietrich, Andrea M., Isaacman-VanWertz, Gabriel, Tanko, James M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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