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ISIAQ Webinar: “New instrumentation/monitoring techniques for faster knowledge”

February 13, 2019 @ 9:00 am - 10:00 am

ISIAQ STC 11 (Sources, Monitoring and Evaluation: Chemical Pollutants) have hosted webinars to increase communication within the STC11 and expanding our outreach. The upcoming webinar will be on the topic of “New instrumentation/monitoring techniques for faster knowledge”.

Date: February 13th, 2019 • 9:00-10:00 am. U.S. Eastern Standard Time

Outlines: Presentations (2×20minutes) and Discussions (20 minutes)

Presentation 1: Time-resolved measurements of volatile organic compounds indoors using a Vocus time-of-flight proton-transfer-reaction mass spectrometer

Presenter: Dr. Demetrios Pagonis

Abstract: Proton-transfer-reaction mass spectrometry (PTR-MS) is a fast, sensitive, on-line technique for measuring volatile organic compounds (VOCs) in the atmosphere. This webinar provides an overview of the principles of PTR-MS, describes a new commercial instrument in the Vocus PTR time-of-flight mass spectrometer, and presents preliminary results of indoor VOC measurements made using the Vocus in a university gym. During these measurements, the Vocus sampled indoor air directly and was also coupled to a gas chromatograph. GC-Vocus measurements allow for greater speciation of indoor VOCs, providing additional insight into indoor chemistry that complements the faster time resolution of ambient measurements.

Biography: Demetrios Pagonis received a chemistry PhD from the University of Colorado in 2018, conducting research in the Ziemann group on the chemistry of the indoor environment, reactions of hydroperoxides in secondary organic aerosol, and the gas-wall partitioning of organic compounds in Teflon chambers and tubing. Demetrios has experience making measurements of gas-phase organic compounds indoors using proton-transfer-reaction mass spectrometry, iodide-adduct chemical ionization mass spectrometry, and nitrate-adduct chemical ionization mass spectrometry. In his work Demetrios incorporates these measurements into box models to understand the sources, transformations, and sinks of organic compounds indoors. Demetrios is currently working as a postdoctoral researcher in the Jimenez group at CU Boulder, leading the deployment of an extractive electrospray mass spectrometer (EESI) aboard the NASA DC-8 in the upcoming FIREX-AQ campaign.

Presentation 2: Evaluation of Gas-Particle Phase Partitioning of Semi- and Intermediately Volatile Organic Compounds using a Thermal desorption Aerosol Gas Chromatograph

Presenter: Ms. Claire Fortenberry

Abstract: The Thermal desorption Aerosol Gas Chromatograph (TAG) system combines in-situ collection of ambient organic aerosol with gas-chromatography-mass-spectrometry (GCMS) to separate, identify, and quantify molecular components with hourly measurement resolution. Recently, the TAG has been modified to incorporate a gas trap for collecting and measuring ambient gas-phase semi- and intermediately volatile organic compounds (S/IVOCs) in parallel with particles. This presentation will provide an overview of TAG measurement and data processing methods, as well as TAG measurements from field campaigns to investigate the influence of natural ventilation on indoor air quality in single-family homes.

Biography: Claire Fortenberry is a PhD candidate in Prof. Brent Williams’s group at Washington University in St. Louis. She develops novel GCMS-based instrumentation to measure ambient organic particles and gases. Using this equipment, she is working to understand phase partitioning of semi- and intermediately volatile organic compounds from a variety of sources and systems, including indoor air. She has deployed the Thermal desorption Aerosol Gas Chromatograph (TAG) in various laboratory and field studies, including the Air Composition and Reactivity from Outdoor aNd Indoor Mixing (ACRONIM) field campaign to investigate indoor air quality in single-family homes.


  • Online meeting ID:dalbertson
  • Join the online meeting: https://join.startmeeting.com/isiaq (you may need to download the APP to watch presentation slides, ask questions, and participate in discussions).
  • Dial-in number (US):(701) 801-1211 Access code: 228-441-045#
  • International dial-in numbers: https://stme.in/i/isiaq


  • Ying Xu (STC 11 Chair, Tsinghua University, China and The University of Texas at Austin, U.S.A.)
  • Dustin Poppendieck (STC 11 Vice Chair, National Institute of Standards and Technology, U.S.A.)
  • Xiaoyu Liu (STC 11 Secretary, Environmental Protection Agency, U.S.A.)