Barbara J. Turpin

O ₂ ⁻ as a CIMS reagent ion enables safer usage and fingerprint ion peaks for PFAS compound confirmation while providing higher sensitivity and lower limits of detection for real-time gas-phase measurements of several PFAS compared to current methods.

This review aims to summarize the effects of per- and poly-fluoroalkyl substances (PFAS) exposures on the lung, emphasizing data coverage across steps of human health risk assessments. There is expansive literature characterizing PFAS contamination in water, but recent studies have identified PFAS as a component of air pollution, thus impacts on the lung have been an increasing point of inquiry. Mounting evidence from human clinical/epidemiological, animal, and in vitro investigations supports relationships between PFAS exposures and adverse pulmonary outcomes including asthma, allergies, infections, and cancer. Focusing on toxicology studies using animal and in vitro lung cell models, exposures to PFAS modulated inflammation/immune responses, oxidative stress, mucus production, surfactant properties, and epithelial barrier integrity, representing important mechanisms impacting pulmonary health. There are expanding datasets linking PFAS exposures to adverse pulmonary outcomes; however, these data originated from mostly oral/ingestion exposure and not from volatilized or aerosolized PFAS exposure designs. Furthermore, there is a general lack of data informing dose-response modeling and risk characterization, representing gaps needed to characterize pulmonary health risks. The online version contains supplementary material available at 10.1007/s11882-026-01273-6.

Healthcare Associated Infections (HAIs) pose a significant public health risk. Hospital sinks and associated plumbing are one likely source. This study investigates bioaerosol emissions from sink P-traps during faucet operation to assess their potential role in pathogen transmission in the hospital context. We designed an aerosol chamber system with adjustable air change rate and a functioning sink meeting hospital standards. We quantified bioaerosol and large droplet emission factors from the sink, using FAmpEscherichia coli as a model for Enterobacteriaceae such as Klebsiella pneumoniae. We cultured Andersen Cascade Impactor and BioSpot sampler aerosol samples and deposition plates using MI agar, which is selective for E. coli. Across five experiments, deposition plate counts were substantial, while air samples were close to detection limits. We estimated PM5.0 bioaerosol emissions factors of 1.3 x 10-10 to 1.9 x 10-10 CFU emitted per CFU in P-trap. Large droplet emission factor was one order of magnitude larger, at 4.3 x 10-9 ± 2.8 x 10-9 CFU per CFU. Results were used to predict Klebsiella pneumoniae inhalation dose (0.78 to 1.12 CFU day-1) and inhalation infection probability (∼10-5) for 5.5 day hospital stay with colonized plumbing (air change rate 6 h-1). This translates to ∼1 infection per year for a hospital with a severe plumbing system colonization affecting ∼2000 continuously occupied rooms. For pathogens with different dose response curves, we demonstrate how infection probability via inhalation depends on dose response.

2-Methyltetrol sulfate diastereomers (2-MTS) form from acid-driven multiphase chemical conversion of inorganic sulfate (Sulf_inorg) aerosol by isoprene-derived epoxydiols (IEPOX). Studies have explored 2-MTS sinks within aerosols, but observations of 2-MTS in atmospheric waters indicate a need to understand the fate of 2-MTS in clouds and fogs. In batch reactor experiments, we oxidized 2-MTS in 30, 300, and 3000 μM solutions to understand 2-MTS fate in cloud, fog, and aerosol water. Ion chromatography (IC) revealed production of acetate, oxalate, and Sulf_inorg with 2-MTS oxidation. Our 30, 300, and 3000 μM experiments revealed a 5%, 20%, and 32% gap in the sulfur mass balance, respectively, suggesting organosulfates (OSs) formed from 2-MTS oxidation. OSs produced by 2-MTS oxidation were detected by hydrophilic liquid interaction chromatography interfaced to electrospray ionization high-resolution tandem mass spectrometry at mass-to-charge ratios 139 (C₂H₃O₅S^–), 169 (C₃H₅O₆S^–), 185 (C₃H₅O₇S^–), 199 (C₄H₇O₇S^–), 211 (C₅H₇O₇S^–), 213 (C₅H₉O₇S^–), 227 (C₅H₇O₈S^–), and 229 (C₅H₉O₈S^–). 2-MTS oxidation was then accurately predicted with a rate constant of 1.5×10⁹ M⁻¹s⁻¹. Results emphasize the utility of 2-MTS for sulfur cycling in the atmosphere, and the potential for IC to measure 2-MTS in atmospheric waters.

Per- and polyfluoroalkyl substances (PFAS) are emerging pollutants of concern, primarily due to their terminal degradation products, which exhibit environmental persistence and mobility. Several groups of PFAS, including hydrofluoroolefins (HFOs), perfluoro olefins (PFOs), perfluoro vinyl ethers (PVEs), and hydrofluoroalkanes (HF-alkanes), are volatile and reside predominantly in the gas phase. PFAS such as HFOs, PFOs, and PVEs are considered reactive and may generate short-chain degradation products that persist in the environment. Despite the importance of these gaseous PFAS, there is a lack of analytical techniques capable of providing high-resolution temporal measurements of potential precursors to terminal degradation products. This study presents the first real-time method for detecting and quantifying atmospheric HFOs, PFOs, PVEs, and HF-alkanes using a high-resolution chemical ionization mass spectrometer (HR-CIMS). Using NO⁺ mixed with O₂⁺ (NO⁺/O₂⁺), and O₂⁺ as reagent ions, the CIMS was able to identify and quantify PFAS via fluoride abstraction (M - F)⁺, hydride abstraction (M - H)⁺, or charge transfer (M⁺) mechanisms. The method achieves 10-s limits of detection (LOD) ranging from 2 to 40 ppt, enabling online monitoring in ambient air, especially near emission sources or in indoor environments. The use of NO⁺/O₂⁺ and O₂⁺ reagent ions with HR-CIMS provides a novel and sensitive approach for real-time detection of PFAS via positive reagent ion modes, especially for emerging gas-phase PFAS that currently lack suitable online measurement techniques to better constrain their atmospheric emissions and concentrations.

At fixed aerosol acidity, we recently demonstrated that dimers in isoprene epoxydiol-derived secondary organic aerosol (IEPOX-SOA) can heterogeneously react with hydroxyl radical (^·OH) at faster rates than monomers. Aerosol acidity influences this aging process by enhancing the formation of oligomers in freshly generated IEPOX-SOA. Therefore, we systematically examined the role of aerosol acidity on kinetics and products resulting from heterogeneous ^·OH oxidation of freshly generated IEPOX-SOA. IEPOX reacted with inorganic sulfate aerosol of varying initial pH (0.5, 1.5, and 2.5) in a steady-state smog chamber to yield a constant source of freshly generated IEPOX-SOA, which was aged in an oxidation flow reactor for 0-22 equiv days of atmospheric ^·OH exposure. Molecular-level chemical analyses revealed that the most acidic sulfate aerosol (pH 0.5) formed the largest oligomeric mass fraction, causing the slowest IEPOX-SOA mass decay with aging. Reactive uptake coefficients of ^·OH (γ_OH) were 0.24 ± 0.06, 0.40 ± 0.05, and 0.49 ± 0.20 for IEPOX-SOA generated at pH 0.5, 1.5, and 2.5, respectively. IEPOX-SOA became more liquid-like for pH 1.5 and 2.5, while exhibiting an irregular pattern for pH 0.5 with aging. Using kinetic and physicochemical data derived for a single aerosol pH in atmospheric models could inaccurately predict the fate of the IEPOX-SOA.