Consumer-level 3D printers emit ultrafine and fine particles, though little is known about their chemical composition or potential toxicity. We report on chemical characteristics of the particles in comparison to raw filaments, and assessments of particle toxicity. Particles emitted from polylactic acid (PLA) appeared to be largely composed of the bulk filament material with mass spectra similar to the PLA monomer spectra. Acrylonitrile butadiene styrene (ABS), extruded at a higher temperature than PLA, emitted vastly more particles and their composition differed from that of the bulk filament, suggesting that trace additives may control particle formation. In vitro cellular assays and in vivo mice exposure all showed toxic responses when exposed to PLA and ABS-emitted particles, where PLA-emitted particles elicited higher response levels than ABS-emitted particles at comparable mass doses. A chemical assay widely used in ambient air-quality studies showed particles from various filament materials had comparable particle oxidative potentials, slightly lower than those of ambient particulate matter (PM_2.5). However, particle emissions from ABS filaments are likely more detrimental when considering overall exposure due to much higher emissions. Our results suggest that 3D printer particle emissions are not benign and exposures should be minimized.

Electronic nicotine delivery systems (ENDS) aerosols are complex mixtures of chemicals, metals, and particles that may present inhalation hazards and adverse respiratory health risks. Despite being considered a safer alternative to tobacco cigarettes, metal exposure levels and respiratory effects associated with device aging and vaping frequency have not been fully characterized. In this study, we utilize an automated multi-channel ENDS aerosol generation system (EAGS) to generate aerosols from JUUL pod-type ENDS using tobacco-flavored e-liquid. Aerosol puff fractions (1–50) and (101–150) are monitored and sampled using various collection media. Extracted aerosols are prepared for metal and toxicological analysis using human primary small airway epithelial cells (SAEC). ENDS aerosol-mediated cellular responses, including reactive oxygen species (ROS), oxidative stress, cell viability, and DNA damage, are evaluated after 24 h and 7-day exposures. Our results show higher particle concentrations in later puff fractions (0.135 mg/m³) than in initial puff fractions (0.00212 mg/m³). Later puff fraction aerosols contain higher toxic metal concentrations, including chromium, copper, and lead, which elicit increased levels of ROS followed by significant declines in total glutathione and cell viability. Notably, a 30% increase in DNA damage was observed after 7 days because of later puff fraction exposures. This work is consistent with ENDS aerosols becoming more hazardous across the use of pre-filled pod devices, which may threaten respiratory health.

Particles and volatile organic compounds (VOCs) have been detected emitting from material extrusion 3D printing, which is widely used in nonindustrial environments. However, vat polymerization 3D printing that is also commonly used has yet to be well-characterized for its emissions. In this study, we measured particle and VOC emission rates from stereolithography (SLA) 3D printing during print and post-processing wash and cure processes individually using a standardized testing method for 3D printer emissions in an exposure chamber. We observed minimal particle emissions and identified 30 to over 100 individual VOCs emitted from each operating phase, some of which accumulated after the printing ended. The total VOC emissions from SLA processes were higher than typical levels from material extrusion 3D printing, and the emission rate could be over 4 mg/h. Major VOCs emitted were associated with the resin and chemicals used in print and post-processing procedures, which included esters, alcohols, aldehydes, ketones, aromatics, and hydrocarbons. Emissions from post-processing units were lower than those from printing but also included chemicals with health concerns. The emitted mixture of sensitizers, carcinogens, irritants, and flammable chemicals may present a hazard for indoor air quality and human health. The estimated personal exposure to total VOC and some specific VOCs of concern to human health, like formaldehyde and naphthalene, exceeded the recommended indoor levels (e.g., California Office of Environmental Health Hazard Assessment), potentially causing irritation and other health impacts for 3D printer users.

Material extrusion 3D printing has been widely used in industrial, educational and residential environments, while its exposure health impacts have not been well understood. High levels of ultrafine particles are found being emitted from 3D printing and could pose a hazard when inhaled. However, metals that potentially transfer from filament additives to emitted particles could also add to the exposure hazard, which have not been well characterized for their emissions. This study analyzed metal (and metalloid) compositions of raw filaments and in the emitted particles during printing; studied filaments included pure polymer filaments with metal additives and composite filaments with and without metal powder. Our chamber study found that crustal metals tended to have higher partitioning factors from filaments to emitted particles; silicon was the most abundant element in emitted particles and had the highest yield per filament mass. However, bronze and stainless-steel powder added in composite filaments were less likely to transfer from filament to particle. For some cases, boron, arsenic, manganese, and lead were only detected in particles, which indicated external sources, such as the printers themselves. Heavy metals with health concerns were also detected in emitted particles, while their estimated exposure concentrations in indoor air were below air quality standards and occupational regulations. However, total particle exposure concentrations estimated for indoor environments could exceed ambient air fine particulate standards.

Chemical emissions from building materials may significantly impact indoor air quality and potentially human health, since individuals spend most of their time indoors. With rising global temperatures and more frequent heatwaves, building materials’ resilience becomes more crucial for indoor air quality and structural integrity. However, the effects of temperature rise on building material emissions are not systematically studied. This study investigates the effect of a moderate temperature rise on the volatile organic compound (VOC) and aldehyde emissions of eighteen commonly used building materials, such as engineered hardwood, nylon carpet, terrazzo flooring, and acoustic tile, at two elevated yet realistic temperature points. The chemical emissions were collected using a micro-chamber setup and analyzed using thermal desorption/gas chromatography/mass spectrometry and high-performance liquid chromatography. The results showed that 78% of the materials tested demonstrated increased chemical emissions at higher temperatures. Wood-flooring materials showed statistically significant increases in formaldehyde at elevated temperatures, which could be associated with health risks. Eight of the tested materials, particularly those used in large surface area applications, showed significant increases in emissions at increased temperatures, and half of these were labeled as “low-VOC”. These findings may inform the updating of building standards and third-party certification with respect to temperature variation when assessing building material emissions. This research aims to provide a comprehensive understanding of VOC and aldehyde emissions at emerging indoor environmental conditions due to extreme heat climate scenarios.