Date of Graduation
School of Public Health
Occupational & Environmental Health Sciences
M. Abbas Virji
Introduction: Toxicology and epidemiology studies have observed an association between ultrafine particles (UFPs) and respiratory, cardiovascular, and neurological health effects. While there is a paucity of data in the literature on the potential toxicity and health effects from indoor UFP exposure, more exposure assessment studies and research evaluating the efficacy of controls is merited. An increased demand for efficiency, productivity, and manufacturing has led to conception of laser and 3- dimmensional (3-D) printers in various indoor workplaces. The indoor environment is one of the most important determinants of personal exposure. Introducing laser and 3-D printers to indoor workplaces, introduces a potential indoor source of UFP emissions. Given the current knowledge on the potential health effects from exposure to UFPs, Further research is needed to fully characterize occupational exposures to printer emissions and evaluate factors influencing exposures to better guide control strategies. Methods: The source-receptor model was used to identify relevant factors that may affect emissions and worker exposure. Mixed-effects regression modeling was used to identify sources of variability in exposure to laser printer emissions. UFP and copollutant emissions from laser printers were measured in a laboratory chamber to test the hypothesis that device-specific factors (e.g. make-model, technology, print speed, voltage) influence printer emission profiles. Results are described in Chapter 2. Realtime air samples for UFPs were collected at a laser printing facility. Emission rates for laboratory and real-world exposures were calculated using a one-box model and compared to emission rates calculated using the test method for hard copy devices to determine if results were significantly different. Results are described in Chapter 3. Real-time and time-integrated personal and area air sampling was performed to characterize indoor UFP and co-pollutant exposures to 3-D printer emissions during industrial printing. Personal and area air levels were characterized during industrial 3-D printing and post-processing tasks to determine if exposures were above occupational exposure limits. Results are described in Chapter 4. Conclusions: Device-specific factors such as, copy rate and printer voltage affect exposure. Laser printers evaluated in this study had higher between-device variance. Control strategies should focus on device-specific factors (e.g. copy rate). Future research will focus on other factors potentially influencing exposure (e.g. toner type, paper type). The test method for hard copy devices emission rates differed significantly differed from the one-box model emission rates. Continued research will use exposure and dose modeling to provide estimates and distributions that are meaningful or comparable to previously published data. Occupational exposures to metals and organic vapors during industrial 3-D printing were below respective occupational exposure limits. Further research is needed to fully characterize exposure and understand determinants (e.g. materials, tasks) of higher or lower exposure.
Johnson, Alyson R., "Laser and 3-Dimensional Printers: Characterizing Emissions and Occupational Exposures" (2018). Graduate Theses, Dissertations, and Problem Reports. 5893.