About

Professor Coty Jen joined the chemical engineering department at Carnegie Mellon University in the Fall of 2018 after completing her postdoctoral research with Dr. Allen Goldstein at The University of California, Berkeley, and earning her PhD with Dr. Peter McMurry at the University of Minnesota-Twin Cities. Her research focuses on atmospheric new particle formation and the development of novel instrumentation to measure freshly nucleated particles in diverse environments. Additionally, her work investigates sources of organic nitrogen emissions and the health impacts of wildfire smoke. Outside of her professional work, Professor Jen enjoys a variety of activities including woodworking, cooking, attending musicals and plays, visiting museums, canoeing, sailing, swimming, hiking, biking, gardening, traveling around the world, reading books, and writing short stories. She is described as always working on some interesting topic.

Research topics

• Environmental science
• Chemistry
• Environmental chemistry
• Atmospheric sciences
• Thermodynamics
• Astrobiology
• Meteorology
• Physics
• Astrophysics
• Geology
• Organic chemistry
• Photochemistry

Selected publications

• Measurements of H2SO₄ and SO₃ in Pittsburgh, PA, Fall 2023 and 2024

  KiltHub Repository · 2026-03-10

  datasetOpen accessSenior author

  This dataset includes timelines for Observations of Nocturnal Sulfuric Acid Formation in Pittsburgh, PA. The measurements were taken from Doherty Hall using a chemical ionization mass spectrometer and particle sizing devices. The dataset includes full timelines of H₂SO₄, SO₃, (H₂SO₄)₂, and condensation sink and limited timelines of particle size distributions.

  PublisherDOI

• UCB-GLOBES: An open-access mass spectral database of identified and unidentified atmospheric organic compounds

  2026-02-05

  articleOpen access

  Abstract. Chemical characterization of atmospheric organic aerosols using gas chromatography with 70 eV electron ionization mass spectrometry (GC/EI-MS) has been used for decades in advancing molecular marker detection and identification, though primarily through suspect screening and/or targeted analyses. To advance non-targeted analyses of environmental samples, we have catalogued approximately 27,000 mass spectra (MS) of semi-volatile organic aerosol (OA) analytes observed in ambient samples from the U.S. and the Central Amazon and/or laboratory simulations of secondary OA (SOA) formation in the open-access University of California Berkeley Goldstein Library of Organic Biogenic Environmental Spectra (UCB-GLOBES). These samples are representative of OA under urban and biomass burning influences as well as SOA derived from biogenic precursors (e.g., isoprene, monoterpenes, sesquiterpenes) and biomass burning intermediates. MS are documented in UCB-GLOBES without regard to known chemical identity, annotated with extensive metadata such as sample source/experimental conditions, structural information gained from MS analyses, and predicted chemical properties such as average carbon oxidation state and carbon number. UCB-GLOBES MS are compatible for importing into NIST MS Search program, and we have also provided a Jupyter Notebook for MS visualization and comparisons. We demonstrate the utility of UCB-GLOBES through MS reanalyses of prior analytes observed in ambient data, finding a 20 % reduction in the number of analytes assigned to OA source categories reliant solely on time series correlation and an overall 11 % increase in new MS-based OA source categorization for the Southeast U.S. For 1,513 analytes observed previously in the Central Amazon, we found 375 MS matches using UCB-GLOBES vs. 136 MS matches during prior analyses, representing a 14 % gain in newly confirmed or newly categorized OA species. While OA from laboratory oxidation experiments in UCB-GLOBES are highly diverse chemically, on average only 29 % of UCB-GLOBES MS have a mass spectral match to another MS entry in UCB-GLOBES and/or in the NIST MS Database. This indicates that roughly 70 % of UCB-GLOBES MS are unique thus far, not observed more than once among the laboratory oxidation samples and ambient data in UCB-GLOBES MS. Further, only 18 % can be positively identified in the NIST MS database or with known authentic standards. This points to a large gap between these laboratory simulations and ambient OA. Overall, the UCB-GLOBES database can be utilized for improving confidence in OA source categorization and/or identification, novel chemical marker discovery, tracking chemical diversity, de novo structure and properties prediction, and improving MS search and matching algorithms. inform future research priorities for the chemical characterization of atmospheric organic samples.

  PublisherOA PDFDOI

• Observations of Nocturnal Sulfuric Acid Formation in Pittsburgh, PA

  Environmental Science & Technology · 2026-04-10

  articleOpen accessSenior authorCorresponding

  Measurements of sulfuric acid (H2SO4) and sulfur trioxide (SO3) were conducted in Pittsburgh, Pennsylvania, during field campaigns in Fall 2023 and Fall 2024. These measurements identified nocturnal concentrations of H2SO4 comparable to those of daytime values. Nocturnal H2SO4 concentrations were observed to increase by 5 × 105 to 5 × 107 molecules cm–3 above background on 16 of the 31 measurement nights. The median peak concentration during events was 6.5 × 106 molecules cm–3, with a maximum of 1.0 × 108 molecules cm–3, exceeding previously reported nighttime concentrations. Increases in H2SO4 concentrations were positively correlated with the anomalously high SO3 concentrations and condensation sink rates, indicating that the formation of H2SO4 increased to overcome the loss rates to particles. Increases in particulate mass and the mass fraction of metals commonly emitted from coal combustion and steel production were also observed. The air masses were traced back to the southeast of Pittsburgh, a region home to a steel mill, coke plant, and a steel processing plant. The observations indicate a previously unrecognized nighttime formation pathway for H2SO4, potentially from heterogeneous catalysis with metal or black carbon, originating from steel and coke plant emissions. Further measurements are needed to identify key compounds and chemical processes driving these increases in nocturnal H2SO4 concentrations.

  PublisherDOI

• Supplementary material to "UCB-GLOBES: An open-access mass spectral database of identified and unidentified atmospheric organic compounds"

  2026-02-05

  article
  PublisherDOI

• Comment on egusphere-2026-116

  2026-04-06

  peer-reviewOpen access

  <strong class="journal-contentHeaderColor">Abstract.</strong> Chemical characterization of atmospheric organic aerosols using gas chromatography with 70 eV electron ionization mass spectrometry (GC/EI-MS) has been used for decades in advancing molecular marker detection and identification, though primarily through suspect screening and/or targeted analyses. To advance non-targeted analyses of environmental samples, we have catalogued approximately 27,000 mass spectra (MS) of semi-volatile organic aerosol (OA) analytes observed in ambient samples from the U.S. and the Central Amazon and/or laboratory simulations of secondary OA (SOA) formation in the open-access University of California Berkeley Goldstein Library of Organic Biogenic Environmental Spectra (UCB-GLOBES). These samples are representative of OA under urban and biomass burning influences as well as SOA derived from biogenic precursors (e.g., isoprene, monoterpenes, sesquiterpenes) and biomass burning intermediates. MS are documented in UCB-GLOBES without regard to known chemical identity, annotated with extensive metadata such as sample source/experimental conditions, structural information gained from MS analyses, and predicted chemical properties such as average carbon oxidation state and carbon number. UCB-GLOBES MS are compatible for importing into NIST MS Search program, and we have also provided a Jupyter Notebook for MS visualization and comparisons. We demonstrate the utility of UCB-GLOBES through MS reanalyses of prior analytes observed in ambient data, finding a 20 % reduction in the number of analytes assigned to OA source categories reliant solely on time series correlation and an overall 11 % increase in new MS-based OA source categorization for the Southeast U.S. For 1,513 analytes observed previously in the Central Amazon, we found 375 MS matches using UCB-GLOBES vs. 136 MS matches during prior analyses, representing a 14 % gain in newly confirmed or newly categorized OA species. While OA from laboratory oxidation experiments in UCB-GLOBES are highly diverse chemically, on average only 29 % of UCB-GLOBES MS have a mass spectral match to another MS entry in UCB-GLOBES and/or in the NIST MS Database. This indicates that roughly 70 % of UCB-GLOBES MS are unique thus far, not observed more than once among the laboratory oxidation samples and ambient data in UCB-GLOBES MS. Further, only 18 % can be positively identified in the NIST MS database or with known authentic standards. This points to a large gap between these laboratory simulations and ambient OA. Overall, the UCB-GLOBES database can be utilized for improving confidence in OA source categorization and/or identification, novel chemical marker discovery, tracking chemical diversity, <em>de novo </em>structure and properties prediction, and improving MS search and matching algorithms. inform future research priorities for the chemical characterization of atmospheric organic samples.

  PublisherDOI

• Measurements of H2SO₄ and SO₃ in Pittsburgh, PA, Fall 2023 and 2024

  KiltHub Repository · 2026-03-10

  datasetOpen accessSenior author

  This dataset includes timelines for Observations of Nocturnal Sulfuric Acid Formation in Pittsburgh, PA. The measurements were taken from Doherty Hall using a chemical ionization mass spectrometer and particle sizing devices. The dataset includes full timelines of H₂SO₄, SO₃, (H₂SO₄)₂, and condensation sink and limited timelines of particle size distributions.

  PublisherDOI

• A reactive condensation particle counter for measuring atmospherically relevant concentrations of sulfuric acid

  Aerosol Science and Technology · 2025-02-13

  articleSenior authorCorresponding
  PublisherDOI

• Advancing aerosol science through early career research

  Aerosol Science and Technology · 2025-05-19

  article1st authorCorresponding
  PublisherDOI

• New Library-Based Methods for Nontargeted Compound Identification by GC-EI-MS

  Journal of the American Society for Mass Spectrometry · 2025-01-14 · 12 citations

  articleOpen access

  While gas chromatography mass spectrometry (GC-MS) has long been used to identify compounds in complex mixtures, this process is often subjective and time-consuming and leaves a large fraction of seemingly good-quality spectra unidentified. In this work, we describe a set of new mass spectral library-based methods to assist compound identification in complex mixtures. These methods employ mass spectral uniqueness and compound ubiquity of library entries alongside noise reduction and automated comparison of retention indices to library compounds. As a test data set, we used a publicly available electron ionization mass spectrometry data set consisting of 4833 spectra of particulate organic compounds emitted by combustion of wildland fuels. In the present work, spectra in this data set were first identified using the NIST 2023 EI-MS Library and associated batch process identification software (NIST MS PepSearch) using retention-index corrected Identity Search scoring. Resulting identifications and related information were then employed to parametrize other factors that correlate with identification. A method for identifying compounds absent from but related to those present in mass spectral libraries using the Hybrid Similarity Search is illustrated. Nevertheless, some 90% of the spectra remain unidentified. Through comparison of unidentified to identified mass spectra in this data set, a new simple measure, namely median relative abundance, was developed for evaluating the likelihood of identification.

  PublisherDOI

• Detection efficiency of a water condensation particle counter using electrically neutral sulfuric acid and sulfuric acid-dimethylamine clusters

  Aerosol Science and Technology · 2025-05-06 · 1 citations

  articleSenior authorCorresponding
  PublisherDOI

Recent grants

• AGS-PRF: Molecular Level Characterization of Amino Acids in Atmospheric Aerosols

  NSF · $172k · 2015–2017

• Measuring Sulfuric Acid Nucleation Potential to Develop a Generalized, Semi-Empirical Nucleation Model for the Atmosphere

  NSF · $681k · 2019–2024

Frequent coauthors

• Peter H. McMurry

  29 shared

• Jun Zhao

  Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)

  28 shared

• A. H. Goldstein

  26 shared

• Kelley C. Barsanti

  University of California, Riverside

  24 shared

• David R. Hanson

  17 shared

• Lindsay E. Hatch

  University of California, Riverside

  15 shared

• Pawel K. Misztal

  UK Centre for Ecology & Hydrology

  13 shared

• Amélie Bertrand

  Paul Scherrer Institute

  12 shared

Labs

• Jen Research LabPI

  Focuses on atmospheric new particle formation, developing novel instrumentation, sources of organic nitrogen emissions, and health impacts of wildfire smoke.

Education

• B.S.

  Columbia University

  2010

• M.S., Chemical Engineering

  University of Minnesota, Twin Cities

  2013

• Ph.D., Mechanical Engineering

  University of Minnesota, Twin Cities

  2015

Awards & honors

• NSF GRFP
• NSF AGS Postdoctoral Fellowship
• American Association of Aerosol Research Friedlander Award
• 2024 Dean’s Early Career Fellowships