Date of Award
12-22-2023
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
An average adult inhales 13,500 to 17,500 L of air each day. As oxygen and carbon dioxide are exchanged, the respiratory tract also uptakes a portion of particles and other gases. While this exposure route can be exploited for benefit in drug delivery applications, inhalation of some constituents of ambient air can be detrimental to human health. These health effects are established in some cases, such as for carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and pathogen-laden particles. In contrast, while exposure to certain volatile organic compounds (VOCs) has been associated with pulmonary disease, reproductive disorders, and cancer, health effects for many members of this diverse compound class have not been studied in part due to challenges in acquiring the measurements to inform epidemiological studies. Even for species with established health effects, indoor or outdoor measurements may be required to identify at-risk populations, investigate sources, and motivate interventions. Finally, interventions should be tested for effectiveness. This dissertation has three themes which span instrument development, indoor and outdoor measurements, and evaluation of interventions for a range of gas and particle species with potential or established health effects: 1. Development of a novel instrument to enable investigation of volatile organic compound (VOC) exposure and health effects: Chapter 2 describes the development and characterization of the Multichannel Organics In situ enviRonmental Analyzer (MOIRA), which is designed for mobile measurements of VOCs by thermal desorption – gas chromatography – mass spectrometry with electron ionization. The four measurement channels of this new instrument continuously measure VOCs in the pentane to pentadecane range at 10 min time resolution with detection limits < 100 ppt. The instrument is characterized under different environmental conditions in the laboratory as well as in a pilot study of indoor air in a single-family residence and pilot mobile measurements of ambient air in an urban environment, which are described in more depth in Chapter 3. 2. Air quality measurements to assess ambient concentrations of CO and PM in Haiti and PAHs in Mongolia: In Chapter 4, mid-cost integrated low-cost sensor systems are deployed to two sites in Cap Haitien, Haiti for ambient measurements of PM and CO. Chapter 5 describes measurements of speciated PAHs and other organic molecular markers from filter samples collected at four sites in Ulaanbaatar, Mongolia by collaborators in 2013. 3. Evaluation of interventions for reducing inhalation exposure to pathogen-laden particles: In Chapter 6, a simple model explains elevated CO2 levels within the patient compartment of a stretcher transport isolator, which is designed to protect healthcare workers from hazards which include pathogen-laden particles emitted by the patient. Chapter 7 evaluates the filtration, fit, and breathability of open-source improvised respiratory protection designs and materials, including 3D-printed designs, which were proposed in response to shortages of commercial personal protective equipment during the COVID-19 pandemic. Finally, Chapter 8 considers the relevance of material filtration measurements in a filter holder for the filtration efficiency of a sewn mask mounted to a mannequin head. Throughout this work, aerosol and gas measurement technologies ranging from low-cost sensors to a new custom mass spectrometry instrument are used to further the investigation or mitigation of a species’ impact on human health.
Language
English (en)
Chair
Brent Williams