Grantee Research Project Results
2022 Progress Report: Development of High-Resolution Chemical Ionization Mass Spectrometry Methods for Real-Time Measurement of Emerging Airborne Per- and Polyfluoroalkyl Substances (PFASs)
EPA Grant Number: R840431Title: Development of High-Resolution Chemical Ionization Mass Spectrometry Methods for Real-Time Measurement of Emerging Airborne Per- and Polyfluoroalkyl Substances (PFASs)
Investigators: Surratt, Jason D. , Zhang, Yue , Turpin, Barbara J , Brooks, Sarah D , Zhang, Zhenfa
Institution: University of North Carolina at Chapel Hill , Texas A & M University
EPA Project Officer: Chung, Serena
Project Period: May 1, 2022 through April 30, 2025 (Extended to April 30, 2026)
Project Period Covered by this Report: May 1, 2022 through April 30,2023
Project Amount: $799,833
RFA: Measurement and Monitoring Methods for Air Toxics and Contaminants of Emerging Concern in the Atmosphere (2021) RFA Text | Recipients Lists
Research Category: PFAS Detection , Air Quality and Air Toxics
Objective:
Our overarching hypothesis for this study is that high-resolution chemical ionization time-of-flight mass spectrometers (HR-ToF-CIMS) using iodide (I-), nitrate (NO3-), hydronium (H3O+), or nitrosyl (NO+) reagent ions can efficiently measure airborne PFASs in real-time down to parts per trillion or even sub-ppt levels. To address this hypothesis, we have 3 major objectives, including: (1) determine HR-ToF-CIMS calibration curves and detection limits for atmospherically-relevant PFASs by using commercially-available or synthesized standards; (2) oxidize these PFAS standards with hydroxyl radicals (OH)/ozone (O3) in controlled laboratory settings to generate commercially-unavailable PFAS and to also gain insights into their atmospheric transformations/fates; and (3) deploy a mobile laboratory with these newly developed/lab-validated CIMS methods and other air- and particle-phase sampling techniques at a stationary point source to study fugitive PFAS emissions and their near-source downwind chemistry.
Progress Summary:
- We have performed calibrations of many PFAS chemical classes (i.e., FTOHs, PFCAs, PAPs, diPAPs, FTAcrs, FTSs, FOSEs, FOSAs, GenX, perfluroalkyl vinyl ethers, and poly- and perfluoro epoxides) that are commercially available using the proposed CIMS techniques. By carefully generating their calibration curves, we have now fully determined sensitivities, limits of detection (LODs) and limits of quantification (LOQs) for 10 of the 43 PFAS standards tested using the I-HR-ToF-CIMS method. Using the calibrated and optimized I-HR-ToF-CIMS method, we have measured some of these PFAS in real-time during indoor air perturbation experiments.
- Initial testing deployments of TAMU’s mobile lab facility was done to measure atmospherically-relevant PFAS compounds near a known PFAS point source in TX; HFO, which is known to be produced in large quantities by this point source, was measured in real-time from ambient air by one of our CIMS instruments onboard this mobile lab facility. These initial test deployments of TAMU’s mobile lab facility have helped prepare us for our full field deployment near Chemours in Fayetteville, NC, in Year 3 of our study.
- We performed oxidation of a selected PFAS compound under controlled laboratory settings to derive the yield and identity of atmospheric chemical transformation products of PFAS emissions. These studies will also help to inform our Year 3 mobile lab field deployment near Chemours in Fayetteville, NC.
Future Activities:
- Finish remaining PFAS calibrations using the I-HR-ToF-CIMS and Vocus-CIMS operated with H3O+.
- Conduct calibrations of all 43 commercially-available standards on the HR-ToF-CIMS equipped with NO3- reagent ion chemistry and on the Vocus-CIMS with NH4+ reagent ion chemistry.
- Continue oxidation flow reactor experiments of reactive PFAS, focusing on unsaturated PFAS such as HFO, vinyl ethers, and FTOHs. These experiments will help to identify gas- and particle-phase products formed from atmospheric chemical oxidation of PFAS.
- Continue to prepare for Year 3 deployment of the TAMU mobile lab facility near Chemours in Fayetteville, NC, by deploying the TAMU mobile lab facility with one of our CIMS instruments during summer 2023 to determine HFO seasonal variability near an industrial manufacturing facility that produces this compound in TX.
Journal Articles:
No journal articles submitted with this report: View all 16 publications for this projectSupplemental Keywords:
GenX, PFOS, PFOA, organic fluorine, environmental chemistry, analytical, measurement methods, southeast U.S., North Carolina (NC), fine particulate matter (PM2.5), atmospheric chemistry, air pollution, and EPA Region 4Relevant Websites:
Jason D. Surratt, PhD Bio Exit
Barbara J. Turpin, PhD Bio Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.