Grantee Research Project Results
2022 Progress Report: Development of a reference method for open-path remote sensing of air toxics
EPA Grant Number: R840426Title: Development of a reference method for open-path remote sensing of air toxics
Investigators: Stutz, Jochen , Polidori, Andrea , Pikelnaya, Olga , Low, Jason
Institution: University of California Los Angeles, , South Coast Air Quality Management District
EPA Project Officer: Chung, Serena
Project Period: May 1, 2022 through April 30, 2025
Project Period Covered by this Report: May 1, 2022 through April 30,2023
Project Amount: $798,825
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:
The objective of this project is to develop an open-source reference instrument and methodology for operation, validation, and QA/QC of open-path optical remote sensing (OP-ORS) monitoring of volatile organic compounds (VOCs) and other air toxics. This work is essential to firmly establish OP-ORS as a reliable and trusted tool to monitor VOC and air toxic releases from industrial facilities and for community air quality monitoring of these compounds.
Progress Summary:
Activities in the reporting period have focused on the development and construction of the reference OP-ORS instrument for monitoring of air toxics, pursuing the original goals of our project. The instrument consists of three parts: 1) Telescope with auto-alignment capabilities and fiber optics; 2) Optics and electronics unit which includes LED light source, spectrometer, detector, computer, and all associated electronics; and 3) Quartz retroreflector array.
The telescope, and all associated parts were developed using commercial CAD software to allow for easy replication in the future. After the initial design and the purchase of the relevant material, including machining of custom parts, a prototype was constructed and extensively tested in our laboratory for accuracy and reliability of the alignment mechanism needed to maintain aim onto the retroreflector array. We aligned the telescope and characterized its optical performance. A new camera system was developed to help in the remote aiming of the telescope in the field. We purchased all the parts for the optics/electronics unit and manufactured the custom parts needed to assemble the LED light source, thermal stabilization of light source and spectrometer, spectrometer-fiber adapter, etc. Each of these elements was tested in the laboratory. A housing for the retroreflector array was designed and built. The array has been assembled and is ready for deployment. Instrument construction and testing efforts were accompanied by development of the software tools required to automatically operate the system. We maintain construction plans and part list that will form the basis of the design document that is one of the deliverables of this project. It should be noted that instrument construction began 3 months later than anticipated due to problems with timely delivery of the relevant parts. We will make up for these delays over Summer 2023 and return to our original time plan in year 2.
In close collaboration between UCLA and South Coast AQMD we are further refining our plan to validate the reference OP-ORS instrument and are exploring the deployment options for the initial test of the reference instrument. These plans, as well as the design of the reference OP-ORS system, are developed following the requirements of the project QAPP.
In summary, we have made good progress towards the goals of our project, despite the long delivery times for crucial parts in the aftermath of the COVID pandemic. We expect to continue on our proposed timeline, reaching our goals by the end of the project.
Future Activities:
In the next year of our project, we plan to test the reference OP-ORS instrument in the open atmosphere on the UCLA campus. This first phase will also include an in-situ ozone monitor, calibrated by South Coast AQMD, to develop a realtime validation methodology of the instrument performance. In the second validation experiment we will perform benzaldehyde release experiments to compare established gas-chromatographic observations with the OP-ORS. Both validation exercises will build trust in the reference OP-ORS performance and are crucial before the deployment of the reference system at a local refinery in Year 3. We will compile the details of the instrument as well as our experience in field operation/validation in a design document, as per the original workplan. We are planning to present first results of our project at the Fall Meeting of the American Geophysical Society and the Air & Waste Management Association Methods and Technology meeting.
Supplemental Keywords:
air toxics monitoring, facility emission measurements, fenceline reference methodThe 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.