3-D printing is an additive manufacturing process involving the injection of melted thermoplastic polymers, which are then laid down in layers to achieve a pre-designed shape. The heated deposition process raises concerns of potential aerosol and volatile organic compounds (VOC) emission and exposure. The decreasing cost of desktop 3-D printers has made the use of 3-D printers more acceptable in non-industrial workplaces lacking sufficient ventilation. Meanwhile, little is known about the characteristics of 3-D printing fume emission. The objective of this study was to characterize aerosols and VOC emissions generated from various filaments used with a low-cost 3-D printer in an environmental testing chamber. A pre-designed object was printed in 1.25 hours using eight types of filaments. A scanning mobility particle sizer and an aerodynamic particle sizer were employed to measure the particle size distribution in sub-half-micron fraction (<0.5 µm) and super-half-micron fraction (0.5-20 µm), respectively. VOC concentration was monitored real-time by a photoionization detector and sampled with a tri-sorbent thermal desorption tube, and analyzed by thermal desorption gas chromatography mass spectrometry (TD-GC/MS). Results showed high levels of fume particles emission rate (1.0 × 107 to 1.2 × 1010 #/min) in the sub-half-micron range with mode sizes of 41-83 nm. Particle concentrations peaked during the heat-up and solid layer printing periods. Total VOC concentration in the chamber followed a first-order buildup, with predominant VOC species in the chamber were breakdown and reaction products of the filaments, such as styrene from ABS filaments. These findings and exposure scenario estimation suggest that although the VOC concentrations were much lower than occupational exposure limits, particles with size less than micron might be a concern for users of low-cost 3-D printers due to high respirablity, especially if used in settings without proper guidance and engineering control.
Keywords: 3-D printer; aerosols; volatile organic compounds.