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.

SUMMARY: Upholstered furniture remains a consumer fire hazard. Flame retardant technologies are necessary but may present a health risk from chemical exposure. This study developed methodologies for measuring exposure to flame retardants and flammability performance, comparing the effectiveness of differing flammability reduction strategies on upholstered chairs with and without added flame retardants and the use of a barrier material. The chemical analysis focused on volatile organic compounds (VOCs) and flame retardants. Open flame tests were conducted on chair assemblies, and smolder resistance tests were conducted on chair materials. Results showed that VOC inhalation exposure during consumer use was low for all chair types. However, VOCs were significantly elevated during the chair burns. The organophosphorus flame retardant used in this study was found in air, settled dust and dermal transfer samples. The chairs with a barrier material demonstrated significantly lower flammability hazards when compared to the other chair types. All assembled chairs did not meet the criteria for smolder testing, suggesting a lack of correlation with open‐flame performance. This study demonstrated that combined human health and flammability advantages may be achieved for upholstered chairs constructed with an effective fire barrier material without any added flame retardants.

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.

Three-dimensional (3D) printer usage in household and school settings has raised health concerns regarding chemical and particle emission exposures during operation. Although the composition of 3D printer emissions varies depending on printer settings and materials, little is known about the impact that emissions from different filament types may have on respiratory health and underlying cellular mechanisms. In this study, we used an in vitro exposure chamber system to deliver emissions from two popular 3D-printing filament types, acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), directly to human small airway epithelial cells (SAEC) cultured in an air–liquid interface during 3D printer operation. Using a scanning mobility particle sizer (SMPS) and an optical particle sizer (OPS), we monitored 3D printer particulate matter (PM) emissions in terms of their particle size distribution, concentrations, and calculated deposited doses. Elemental composition of ABS and PLA emissions was assessed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). Finally, we compared the effects of emission exposure on cell viability, inflammation, and metabolism in SAEC. Our results reveal that, although ABS filaments emitted a higher total concentration of particles and PLA filaments emitted a higher concentration of smaller particles, SAEC were exposed to similar deposited doses of particles for each filament type. Conversely, ABS and PLA emissions had distinct elemental compositions, which were likely responsible for differential effects on SAEC viability, oxidative stress, release of inflammatory mediators, and changes in cellular metabolism. Specifically, while ABS- and PLA-emitted particles both reduced cellular viability and total glutathione levels in SAEC, ABS emissions had a significantly greater effect on glutathione relative to PLA emissions. Additionally, pro-inflammatory cytokines including IL-1β, MMP-9, and RANTES were significantly increased due to ABS emissions exposure. While IL-6 and IL-8 were stimulated in both exposure scenarios, VEGF was exclusively increased due to PLA emissions exposures. Notably, ABS emissions induced metabolic perturbation on amino acids and energy metabolism, as well as redox-regulated pathways including arginine, methionine, cysteine, and vitamin B3 metabolism, whereas PLA emissions exposures caused fatty acid and carnitine dysregulation. Taken together, these results advance our mechanistic understanding of 3D-printer-emissions-induced respiratory toxicity and highlight the role that filament emission properties may play in mediating different respiratory outcomes.

Evaluating vaping parameters that influence electronic nicotine delivery system (ENDS) emission profiles and potentially hazardous exposure levels is essential to protecting human health. We developed an automated multi-channel ENDS aerosol generation system (EAGS) for characterizing size-resolved particle emissions across pod- and mod-type devices using real-time monitoring instruments, an exposure chamber, and vaping parameters including different ventilation rates, device type and age, e-liquid formulation, and atomizer setup. Results show the ENDS device type, e-liquid flavoring, and nicotine content can affect particle emissions. In general, pod-type devices have unimodal particle size distributions and higher number emissions, while mod-type devices have bimodal size distributions and higher mass emissions. For pod-type devices, later puff fractions emit lower aerosols, which is potentially associated with the change of coil resistance and power during ageing. For a mod-type device, an atomizer with a lower resistance coil and higher power generates larger particle emissions than an atomizer with a greater resistance coil and lower power. The unventilated scenario produces higher particle emission factors, except for particle mass emission from pod-type devices. The data provided herein indicate the EAGS can produce realistic and reproducible puff profiles of pod- and mod-type ENDS devices and therefore is a suitable platform for characterizing ENDS-associated exposure risks.