About

James Samet is a faculty member at the UNC School of Medicine, specializing in cell and molecular mechanisms of inflammatory responses induced by inhalation of ambient air pollutants. His research focuses on understanding how air pollution impacts respiratory health through inflammatory pathways, contributing to the broader field of environmental health and toxicology. Based at the 145 Medical Drive location, he is actively involved in investigating the biological responses to environmental pollutants, aiming to elucidate mechanisms that could inform public health interventions and policies.

Research topics

• Immunology
• Biochemistry
• Biology
• Chemistry
• Internal medicine
• Medicine

Selected publications

• Evaluating real time intracellular redox toxicology using live-cell imaging approaches

  Redox Biochemistry and Chemistry · 2026-01-07 · 1 citations

  articleOpen accessSenior author
  PublisherDOI

• Can disposable masks be worn more than once?

  UNC Libraries · 2025-04-24

  articleOpen accessSenior author
  PublisherDOI

• Does personalization in exposure assessment change ambient air pollution exposure-response relationships? A panel study

  Ecotoxicology and Environmental Safety · 2025-11-01

  articleOpen access

  Accurate exposure assessment is crucial to understand linkages between ambient air pollution and cardiopulmonary disease. Air quality monitors (AQM) are widely used, but do not account for personal behaviors. We compare the exposure-response relationships between ambient air pollution (PM 2.5 and O 3 ) and cardiopulmonary biomarkers in a panel study using both stationary AQM and Exposure Model for Individuals (EMI). Participants (n = 28) underwent 3–5 sessions totaling 134 visits. Participants underwent spirometry and blood sampling. PM 2.5 and O 3 concentrations were calculated for each visit (lag0) and 4 preceding days (lag1–4) using AQM and EMI. A mixed-effects model was applied to examine the associations between exposure and outcomes. AQM and EMI were strongly correlated for PM 2.5 (ρ = 0.89) and moderately correlated for O 3 (ρ = 0.46). Exposure-response relationships for PM 2.5 were similar, with PM 2.5 associated with increased oxLDL at lag1 (12.2 % (95 %CI: 4.5, 20.2) AQM, 17.9 % (95 %CI: 8.1, 27.8) EMI), increased vWF at lag0 (4.27 % (95 %CI: 0.15, 8.39) AQM, 7.12 % (95 %CI: 2.57, 11.67) EMI) and decreased vWF at lag3 −6.5 % (95 %CI: −11.4, −1.6) AQM, −5.6 % (95 %CI: −10.6, −0.7) EMI) and lag4 (-5.4 % (95 %CI: −10.2, −0.7) AQM, −6.7 % (95 %CI: −12.1, −1.3) EMI). O 3 showed more variability, with positive associations with vWF at lag0 (12.9 % (95 %CI: 6.1, 19.7) AQM, −2.77 % (95 %CI: −8.1, 2.6) EMI) and D -dimer at lag1 27.0 % (95 %CI: 0.9, 53.0) AQM, −6.86 % (95 %CI: −26.3, 12.6) EMI), for AQM only, and negative associations with tPA at lag3 for EMI only (-10.0 % (95 %CI: −21.5, 1.4) AQM, −11.2 % (95 %CI: −19.6, −2.8) EMI). Our findings suggest that exposure-response associations to short-term PM 2.5 and oxLDL and markers of coagulation are consistent between the AMQ and EMI methods, implying increased risk for cardiovascular disease. For O 3 , AQM and EMI were less consistent, highlighting the challenges of estimating and modeling O 3 exposure. • AQM and EMI showed strong similar exposure-response associations for PM 2.5 . • PM 2.5 exposure was associated with increased oxLDL and altered levels of vWF. • AQM and EMI were less consistent for O 3 , highlighting challenges estimating and modeling O3 exposure. • O 3 exposure was associated with markers of endothelial activation and coagulation. • Findings suggest increased risk for CVD even at low level PM 2.5 exposure.

  PublisherDOI

• Aerosolized vitamin D attenuates ozone-induced inflammation and transcriptional responses via membrane antioxidant effects in human bronchial epithelial cells

  American Journal of Physiology-Lung Cellular and Molecular Physiology · 2025-09-12 · 2 citations

  articleOpen access

  Vitamin D aerosols have the potential to protect against exposure to ozone and other inhaled oxidants and prevent the development and exacerbation of lung disease. Here, we show that aerosolized vitamin D treatment decreased ozone-induced oxidative stress and inflammatory responses, as well as decreased production of an oxysterol, β-epoxycholesterol, indicating vitamin D may act as a membrane antioxidant in the airway epithelium.

  PublisherDOI

• A novel method for the quantitative assessment of the fitted containment efficiency of face coverings

  UNC Libraries · 2025-03-25

  articleOpen access

  BACKGROUND: Face masks reduce disease transmission by protecting the wearer from inhaled pathogens and reducing the emission of infectious aerosols. Although methods quantifying efficiency for wearer protection are established, current methods for assessing face mask containment efficiency rely on measurement of a low concentration of aerosols emitted from an infected or noninfected individual. METHODS: A small port enabled the introduction of 0.05 µm sodium chloride particles at a constant rate behind the mask worn by a study participant. A condensation particle counter monitored ambient particle numbers 60 cm in front of the participant over 3-minute periods of rest, speaking, and coughing. The containment efficiency (%) for each mask and procedure was calculated as follows: 100 × (1 - average ambient concentration with face covering worn/average ambient concentration with a sham face covering in place). The protection efficiency (%) was also measured using previously published methods. The probability of transmission (%) from infected to uninfected (a function of both the containment efficiency and the protection efficiency) was calculated as follows: {1 - (containment efficiency/100)}×{1 - (protection efficiency/100)}×100. RESULTS: The average containment efficiencies for each mask over all procedures and repeated measures were 94.6%, 60.9%, 38.8%, and 43.2%, respectively, for the N95 mask, the KN95 mask, the procedure face mask, and the gaiter. The corresponding protection efficiencies for each mask were 99.0%, 63.7%, 45.3%, and 24.2%, respectively. For example, the transmission probability for 1 infected and 1 uninfected individual in close proximity was ∼14.2% for KN95 masks, compared to 36%-39% when only 1 individual wore a KN95 mask. CONCLUSION: Overall, we detected a good correlation between the protection and containment that a face covering afforded to a wearer.

  PublisherDOI

• Metadata GAPDH inhibition mediated by thiol oxidation in human airway epithelial cells exposed to an environmental peroxide

  Open MIND · 2025-01-01

  datasetOpen accessSenior author

  Metadata for GAPDH inhibition mediated by thiol oxidation in human airway epithelial cells exposed to an environmental peroxide

  Publisher

• Omega-3 Fatty Acid Intake and Oxylipin Production in Response to Short-Term Ambient Air Pollution Exposure in Healthy Adults

  Toxics · 2025-12-09

  articleOpen access

  Oxylipins are specialized lipid mediators that can have dual functions, either promoting inflammation or supporting resolution. Exposure to air pollution is associated with systemic inflammation that may be modified by oxylipins derived from polyunsaturated fatty acids (FA). In this study, we examined whether short-term air pollution exposure is associated with changes in circulating oxylipins in healthy adults, who were on high- or low-dietary omega-3 fatty acid (n-3 FA) intakes. We measured 56 oxylipin species from participants’ plasma samples and employed mixed-effects models to assess the associations, stratified by n-3 FA groups. Plasma concentrations of oxylipins derived from n-3 FA [e.g., 14-hydroxydocosahexaenoic acid (14-HDHA) & 11-hydroxydocosahexaenoic acid (11-HDoHE), and 12-hydroxyeicosapentaenoic acid (12-HEPE)] were significantly higher in the high n-3 FA group compared to the low group. Conversely, selected oxylipins derived from n-6 FA [e.g., 15-hydroxyeicosatetraenoic acid (15-HETE) and 14,15-Dihydroxyeicosatrienoic acid (14,15-DiHETrE)] were significantly lower in the high n-3 group. Exposure to PM2.5, O3, and NO2 was associated with reductions in pro-inflammatory oxylipins produced by lipoxygenase in the high n-3 FA group, but not in the low group; for example, 12-HETE. Furthermore, participants in the high n-3 group exposed to PM2.5, O3, and NO2 had elevated levels of n-3 FA-derived pro-resolving oxylipins compared to those in the low n-3 group; for instance, 12-HEPE and 14-HDHA & 11-HDoHE. In conclusion, short-term air pollution exposure was associated with lower pro-inflammatory and higher pro-resolving oxylipin levels in the high n-3 FA group. These findings suggest n-3-derived lipid metabolites may promote inflammation resolution induced by air pollution.

  PublisherOA PDFDOI

• A positive pressure system for selective human exposure to gas and particulate mixed atmospheres

  Inhalation Toxicology · 2025-09-14

  articleSenior author

  INTRODUCTION: Exposure to air pollution containing particulates (PM) and gas-phase volatile organic compounds (VOCs), is a leading cause of human morbidity and mortality globally. Devising effective protective public health strategies requires an assessment of the relative contribution of PM and VOCs to the health effects of air pollution exposure. METHODS: To enable studies of VOCs isolated from mixed atmospheres, we developed a positive air pressure exposure system that permits the subject to breathe unimpeded by the pressure drop imposed by filtering respirators. This system uses pumps to draw air through respirator filters and delivers it to a modified positive pressure respirator at a flow rate that exceeds the ventilatory requirements of the wearer, while preventing infiltration of the surrounding atmosphere. RESULTS: Tests showed negligible leaks (<5% flow reduction) and minimal VOC losses (95% recovery) to the system. When tested using an atmosphere containing woodsmoke, PM filters showed effective exclusion of particulates but minimal losses of VOCs, while activated carbon based cartridges effectively removed gaseous compounds and PM. A team member exercising moderately in a woodsmoke atmosphere for 2-hours reported no perveivable odors and experienced no discomfort during an exposure using charcoal filter cartridges. DISCUSSION: We report the development and validation of a novel human exposure system that allows selective exposure to the gaseous fraction of a mixed atmosphere. This system allows for moderate to vigorous exercise of the study subject and can be used in place of an exposure chamber, making it compatible with clinical and field studies.

  PublisherDOI

• Field emission image of wood smoke

  Open MIND · 2025-01-01

  datasetOpen accessSenior author

  Electron microscope image of wood smoke

  Publisher

• Craniometric determinants of the fitted filtration efficiency of disposable masks

  Frontiers in Public Health · 2024-08-20 · 2 citations

  articleOpen accessSenior authorCorresponding

  Introduction: Exposure to harmful aerosols is of increasing public health concern due to the SARS-CoV-2 pandemic and wildland fires. These events have prompted risk reduction behaviors, notably the use of disposable respiratory protection. This project investigated whether craniofacial morphology impacts the efficiency of disposable masks (N95, KN95, surgical masks, KF94) most often worn by the public to protect against toxic and infectious aerosols. This project was registered with ClinicaltTrials.gov (NCT05388201; registration May 18, 2022). Methods: One-hundred participants (50 men, 50 women) visited the Environmental Protection Agency's Human Studies Facility in Chapel Hill, NC between 2022-2023. Craniometrics and 3D scans were used to separate participants into four clusters. Boosting and elastic net regression yielded five measurements (bizygomatic breadth, nose length, bizygomatic nasal arc, neck circumference, ear breadth) that were the best predictors of filtration efficiency based on overall model fit. Fitted filtration efficiency was quantified for each mask at baseline and when tightened using an ear-loop clip. Results: The mean unmodified mask performance ranged from 55.3% (15.7%) in the large KF94 to 69.5% (12.3%) in the KN95. Modified performance ranged from 66.3% (9.4%) in the surgical to 80.7% (12.0%) in the KN95. Clusters with larger face width and neck circumference had higher unmodified mask efficiency. Larger nose gap area and nose length decreased modified mask performance. Discussion: We identify face width, nose size, nose shape, neck circumference, and ear breadth as specific features that modulate disposable mask fit in both unmodified and modified conditions. This information can optimize guidance on respiratory protection afforded by disposable ear-loop masks.

  PublisherOA PDFDOI

Recent grants

• NIH Grant R01HL043153

  NIH · $744k · 1995

• NIH Grant K04HL000951

  NIH · $104k · 1986

• NIH Grant R01CA027187

  NIH · $96k · 1986

Frequent coauthors

• Philip A. Bromberg

  University of North Carolina at Chapel Hill

  102 shared

• Robert B. Devlin

  Environmental Protection Agency

  91 shared

• Andrew J. Ghio

  Environmental Protection Agency

  78 shared

• Steven E. Prince

  Environmental Protection Agency

  58 shared

• Kirby L. Zeman

  University of North Carolina at Chapel Hill

  58 shared

• Lisa A. Dailey

  57 shared

• Emily Sickbert-Bennett

  Oregon Medical Research Center

  56 shared

• David J. Weber

  University of North Carolina at Chapel Hill

  54 shared