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.

The occurrence of thermal runaway (TR) events continues to rise as the need for lithium-ion batteries (LIB) for energy storage increases. However, the inhalation risks associated with LIB TR events remain widely unknown. The objective of this study was to evaluate the impact of LIB TR particulate emission exposures on primary small airway epithelial cells (SAEC). TR was triggered by subjecting lithium-ion cells to thermal abuse at different states of charge (SOC). Two different battery cathode chemistry compositions, namely, nickel manganese cobalt (NMC) or lithium iron phosphate (LFP) were evaluated. Aerosol monitoring and sampling instrumentation were employed followed by physicochemical particle characterization and inhalation dosimetry modeling. SAEC were treated with TR particulate emission extracts for 24 h and 7 days at doses representing a cumulative 1- and 5-year inhalation exposure. Following treatment, cellular viability, reactive oxygen species (ROS) production, and protein expression of DNA damage and epithelial mesenchymal transition (EMT) markers were assessed. TR particulate emissions consisted of ultrafine particles containing a variety of heavy metals. Cellular senescence was induced by NMC-derived TR extracts, but not LFP-derived TR extracts. SAEC treated with the 5-year dose of NMC-derived TR extract, induced significant ROS production. In cells treated with NMC-derived TR extract, regulators of DNA repair and cell cycle arrest were perturbed. Oxidative stress subsequently induced EMT, as SAEC treated with NMC-derived TR particulate emissions reduced E-cadherin expression and upregulated Fascin and Vimentin expression. This study reveals the respiratory implications of TR particulate emissions and the role of battery chemistry.

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.

Material extrusion 3D printing has been widely used in industrial, educational and residential environments. However, the associated emissions and exposure health impacts need to be evaluated, especially for the new and emerging filament materials. This study characterized particle and chemical emissions from 3D printing using five different metal composite filaments, which contain over 90% (by weight) of metal powder blended with polymer binders. The emission characterization was conducted using an exposure chamber following a standard testing method. Real-time particle measurements showed that particle emission rates ranged from 8 × 10⁹ to 2 × 10¹¹ particles/h for particle number and 200 to 1400 µg/h for particle mass. Over 98% of the emitted particles were smaller than 1 µm, which poses an inhalation hazard. Inductively coupled plasma–mass spectrometry analysis detected manganese, copper, zinc, and selenium in emitted particles from all filaments. However, metal powder in raw filaments tended not to be transferred into particle emissions, resulting in the total metals (and metalloids) accounting for 0.07% to 0.95% of emitted particle mass. Sorbent tube sampling and analytical analyses showed various volatile organic compounds emitted during printing, including hydrocarbons, alcohols, aldehydes, and aromatic compounds. Overall, metal composite filaments generated lower levels of volatile organic compounds (VOCs) compared to thermoplastic polymer filaments; in addition, the emitted VOC compositions differed. Organic chemicals associated with metal composite filament emissions included formaldehyde, benzaldehyde, acetaldehyde, naphthalene, and trimethylbenzene, exposure to which may cause irritations or other adverse health impacts. This study estimated personal exposure to hazardous components assuming a person is close to the printer with low ventilation to represent an acute worst-case exposure scenario. Modeled personal exposure to emissions showed potential exceedances of exposure to fine (PM_2.5) and coarse (PM₁₀) particulate matter, arsenic, manganese, formaldehyde, caprolactam, acetaldehyde, and naphthalene compared to reference levels. A modeled office room with ventilation showed reduced exposure levels by up to two orders of magnitude, assuming the same emission source. Users can avoid close proximity to an operating printer and increase dilution through larger room volumes and higher air change rates to reduce potential inhalation exposures at given printing conditions.

This study evaluates the effectiveness of fire barrier solutions for upholstered furniture to enhance passive fire protection and reduce chemical exposure risks during regular use. Upholstered furniture ignition accounts for 22% of fatalities in reported home fires, often due to rapid flame spread and high heat conditions. Given the substantial fuel load presented by upholstered furniture, implementing targeted fire protection strategies to limit fire growth and spread is critical in helping to reduce fatalities. Research suggests that incorporating a fire barrier between the foam cushion and outer textile can delay foam ignition without requiring added flame retardants. This approach not only improves fire safety but also mitigates concerns about chemical exposure from flame retardants detected in dust, air, and burn emissions. This comparative study assessed upholstered cushions with and without a fire barrier using standardized testing methods, including the Smolder Test, elemental analysis, flame retardant testing, and a small‐scale open flame test. Sixteen commercially available barriers were initially evaluated but were eliminated due to deficient performance. A novel fire barrier, developed in collaboration with a fabricator, was tested and found to meet flammability and chemical safety criteria. Full‐scale open flame testing of upholstered cushions revealed that those without a fire barrier burned completely, while those with the barrier textile prevented foam combustion, exhibiting only minimal smoldering. These findings demonstrate that using a fire barrier on upholstered furniture offers an effective solution for reducing fire risks without increasing chemical exposure and highlights an integrated approach to improving fire safety and health outcomes in residential environments.