Grantee Research Project Results
Enabling real-time, low-cost measurement of hazardous air pollutants
EPA Grant Number: R840425Title: Enabling real-time, low-cost measurement of hazardous air pollutants
Investigators: Isaacman-VanWertz, Gabriel , Kroll, Jesse H. , Papapostolou, Vasileios
Institution: Virginia Polytechnic Institute and State University , Massachusetts Institute of Technology
EPA Project Officer: Chung, Serena
Project Period: May 1, 2022 through May 12, 2025
Project Amount: $800,000
RFA: Measurement and Monitoring Methods for Air Toxics and Contaminants of Emerging Concern in the Atmosphere (2021) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics
Objective:
Hazardous air pollutants (HAPs) represent a key target for air monitoring; however, current approaches involve either sample collection followed by offline analysis (which tends to be labor-intensive and poorly time-resolved) or in situ measurement using state-of-the-art research-grade instruments (which tend to be expensive and large). The objective of this project is to develop, characterize, and demonstrate a novel approach to the measurement of organic HAPs. Such measurements must be easily deployable (autonomous and low in cost, size, and power draw) but also able to provide ambient concentrations of individual HAP species in near-real time. This technique would be ideally suited for fenceline monitoring, distributed measurements, source attribution, and community monitoring.
Approach:
Central to this technique is the use of commercially-available low-cost “total VOC” sensors. As stand-alone systems, such sensors have neither the sensitivity nor the selectivity to quantitatively measure individual species within a mixture. Thus this project will focus on improving both sensitivity and selectivity, by: (1) the use of a novel “enriching inlet”, a permeable tube that allows small molecules (e.g., N2, O2) to diffuse out, but larger ones (HAPs) to remain and therefore be concentrated in near real time; (2) a new “inline GC”, in which a short length of gas chromatographic column provides some degree of separation of organic species on sub-minute timescales; and (3) an array of low-cost sensors which exhibit differing responses to different species, providing additional dimensions of chemical resolution. These components will be combined into a prototype instrument, which will first be tested in the laboratory and then deployed to the field (fixed fenceline measurements at refineries and mobile measurements near oil wells). Comparison with co-located regulatory- and research-grade measurements, combined with machine-learning techniques, will enable the data collected from the prototype instrument to be interpreted in terms of identities and concentrations of individual HAP species.
Expected Results:
The primary output of this work is the development, characterization, and validation of a fundamentally new approach to the near real-time quantitative measurement of HAPs. Prototype instruments will be built and deployed, and hardware modifications (different modular components) and data analysis approaches will be characterized in detail. More generally, this approach could be expanded to the routine measurement of other volatile organic compounds (VOCs) as well, for use in monitoring air quality and atmospheric composition.
Publications and Presentations:
Publications have been submitted on this project: View all 2 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 2 journal articles for this projectSupplemental Keywords:
tropospheric, chemicals, environmental chemistry, ambient air, organics, EPA Region 9, analytical, measurement methodsProgress and Final Reports:
The 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.