Dynamic Analysis of Particle Emissions from FDM 3D Printers through a Comparative Study of Chamber and Flow Tunnel Measurements.

Ultrafine particle emissions originating from fused deposition modeling (FDM) three-dimensional (3D) printers have received widespread attention recently. However, the obvious inconsistency and uncertainty in particle emission rates (PERs, #/min) measured by chamber systems still remain, owing to different measurement conditions and calculation models used. Here, a dynamic analysis of the size-resolved PER is conducted through a comparative study of chamber and flow tunnel measurements. Two models to resolve PER from the chamber and a model for flow tunnel measurements were examined. It was found that chamber measurements for different materials underestimated PER by up to an order of magnitude and overestimated particle diameters by up to 2.3 times, while the flow tunnel measurements provided more accurate results. Field measurements of the time-resolved particle size distribution (PSD) in a typical room environment could be predicted well by the flow tunnel measurements, while the chamber measurements could not represent the main PSD characteristics (e.g., particle diameter mode). Secondary aerosols (>30 nm) formed in chambers were not observed in field measurements. Flow tunnel measurements were adopted for the first time as a possible alternative for the study of 3D printer emissions to overcome the disadvantages in chamber methods and as a means to predict exposure levels.