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3D Printer Particle Emissions: Translation to Internal Dose in Adults and Children
Citation:
Byrley, P., W. Boyes, K. Rogers, AND Ann Jarabek. 3D Printer Particle Emissions: Translation to Internal Dose in Adults and Children. JOURNAL OF AEROSOL SCIENCE. Elsevier Science Ltd, New York, NY, 154:1-12, (2021). https://doi.org/10.1016/j.jaerosci.2021.105765
Impact/Purpose:
This manuscript describes potential consumer exposures to airborne particles while using 3D printers and the translation of those exposures using dosimetry modeling to predict inhaled dose metrics in the respiratory system. Fused Deposition Modeling (FDM) 3D printers have been shown to produce airborne particles that are released from the heated feedstock material as it is pushed through the printer's nozzle to create a 3D object. A 3D printer was operated in a 2 m3 chamber using two separate feedstocks: acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA). Ultrafine particle emissions were measured in real-time using a scanning mobility particle sizer. The deposition of these particles in the respiratory system was then predicted using the Multiple-Path Particle Dosimetry (MPPD) model (version 3.04) for Caucasian adult males versus females and children of various ages. 3D printing using ABS was found to produce greater particle exposure concentrations than PLA. As shown for ultrafine particles from other sources, the majority of particle mass was predicted to deposit in the pulmonary (PU) region. Differences were predicted in the total inhaled mass and surface area of particles deposited in the 3 major regions of the respiratory tract, and across different age groups and between male and female adults. Prediction of cumulative retained mass burden in the PU region revealed there was a potential risk for repeated exposure from 3D printer use. These results demonstrate that translation to internal dose should be carefully evaluated when characterizing exposure concerns for 3D printer emission particles, especially when considering the potential exposure for young users. Predicted internal dose should influence the design of in vitro and in vivo type experiments using 3D printer emission particles.
Description:
Desktop fused deposition modeling (FDM) three-dimensional (3D) printers are becoming increasingly popular among home hobbyists. FDM 3D printers have been shown to release ultrafine airborne particles in large amounts, indicating the potential for inhalation exposure and consequent health risks among FDM 3D printer users and other home occupants including children. These particles are generated from the heating of thermoplastic polymer feedstocks during the FDM 3D printing process, with the most commonly used polymers being acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA). Risk assessment of these exposures demands estimation of internal dose, especially to address intra-human variability across life stages. Dosimetry models have proven to effectively translate particle exposures to internal dose metrics relevant to evaluation of their effects in the respiratory tract. We used the open-access multiple path particle dosimetry (MPPD v3.04) model to estimate inhaled particle deposition in different regions of the respiratory tract for children of various age groups from three months to eighteen years old adults. Mass concentration data for input into the MPPD model was calculated using particle size distribution and density data from experimental FDM 3D printer emissions tests using both ABS and PLA. The impact of changes in critical parameters that are principal determinants of inhaled dose, including: sex, age, and exposure duration, was examined using input parameter values available from the International Commission on Radiological Protection. Internal dose metrics used included regional mass deposition, mass deposition normalized by pulmonary surface area, surface area of deposited particles by pulmonary surface area, and retained regional mass. Total mass deposition was found to be highest in the 9-year-old to 18-year-old age groups with mass deposition by pulmonary surface area highest in 3-month-olds to 9-year-olds and surface area of deposited particles by pulmonary surface area to be highest in 9-year-olds. Clearance modeling revealed that frequent 3D printer users are at risk for an increased cumulative retained dose.
URLs/Downloads:
DOI: 3D Printer Particle Emissions: Translation to Internal Dose in Adults and Children