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Harmful emissions including particulates, volatile organic compounds, and aldehydes are generated during three‐dimensional (3D) printing. Ultrafine particles are particularly important due to their ability to penetrate deep into the lung. We modeled inhalation exposure by particle size during 3D printing. A total of six thermoplastic filaments were used for printing under manufacturer's recommended conditions, and particle emissions in the size range between 10 nm and 10 μm were measured. The inhalation exposure dose including inhaled and deposited doses was estimated using a mathematical model. For all materials, the number of particles between 10 nm and 1 μm accounted for a large proportion among the released particles, with nano‐sized particles being the dominant size. More than 1.3 × 109 nano‐sized particles/kgbw/g (95.3 ± 104.0 ng/kgbw/g) could be inhaled, and a considerable amount was deposited in respiratory regions. The total deposited dose in terms of particle number was 3.1 × 108 particles/kgbw/g (63.6% of the total inhaled dose), and most (41.3%) were deposited in the alveolar region. The total mass of particles deposited was 19.8 ± 16.6 ng/kgbw/g, with 10.1% of the total mass deposited in the alveolar region. Given our findings, the inhalation exposure level is mainly determined by printing conditions, particularly the filament type and manufacturer‐recommended extruder temperature. [ABSTRACT FROM AUTHOR]

Ultrafine particles and other hazardous materials are emitted during 3D printing, but the effect of temperature on such particles has not been studied systematically. The aim of this study was to evaluate the effect of temperature on the emission rate of particulate matter during fused deposition modeling (FDM) three‐dimensional (3D) printing using different filament types. The number concentration of particles was measured with direct‐reading instruments in an exposure chamber at various temperatures while using four filament materials during 3D printing. The temperature was increased from 185 to 290°C in 15°C increments, while incorporating the manufacturer‐recommended operating conditions. The emission rate increased gradually as the temperature increased for all filament types, and temperature was the key factor affecting the emission rate after filament type. For all filaments, at the lowest operating temperature, the emission rate was 107‐109 particles/min, whereas the emission rate at the highest temperature was about 1011 particles/min, that is, 100‐10 000 times higher than the emission rate at the lowest temperature. To reduce particle emissions from 3D printing, we recommend printing at the lowest temperature possible or using low‐emission materials. [ABSTRACT FROM AUTHOR]