Day 2: Precision Measurements in Air Quality & Turbulence Incubator
George Nehmetallah
Day 2: Precision Measurements in Air Quality & Turbulence Incubator
This morning the meeting started with a talk by Greg Rieker, from the University of Colorado. His talk was about localizing gas sources using kilometer-scale open-path dual-comb spectroscopy in combination with high resolution transport modeling and inversions. The challenges are to achieve real time transport modeling with a low drift and broadband spectral fitting algorithm resistant to multi-species interference. Along with colleagues at NIST-Boulder, Dr. Rieker and his team developed a fieldable dual-comb spectrometer and explored various transport models dependent on wind conditions and the appropriate length scale. Some of the transport models are: (a) Gaussian plume/Puff, (b) Reynolds- averaged Navier Stokes (RANS), (c) Large Eddy simulation (LES), and (d) Direct numerical simulation (DNS) which is the most powerful but computationally intensive. Dr. Rieker concluded by laying out future plans for deploying the system at Boulder Atmospheric Observatory to localize leaks using a realistic background. Also, one of the future plans is to deploy autonomous UAVs to localize leaks and compare with the land based system.
Following a short coffee break of networking between participants, the 3rd working Session began with a talk by Albert Manninen from VTT Technical Research Centre, Finland. The talk was about metrology for high-impact GHGs. This is a large project in scope, with several goals: (1) Target GHGs and changes to climate impact. This goal was achieved through the development of a new SI traceable GHG reference standards; (2) Improve spectral reference data for atmospheric monitoring (EUMETRISPEC project). This project aims at establishing a high-resolution spectroscopic infrastructure for traceable spectroscopic line data recorded under well controlled conditions at a central spectroscopy facility; and (3) Employ quantum cascade laser spectrometry for radioactive material detection and radioactive emission monitoring. At the end of his talk he suggested future potential monitoring using portable and compact spectrometers of nuclear facilities might be possible.
Joseph Hodges from NIST-Gaithersburg gave a talk about developing standards to support EPA MATS regulations for elemental mercury. He discussed EPA’s mandate on power plant emissions to adhere to NIST standards. Dr. Hodges detailed the mercury-in-air measurement traceability chain and indoor air quality exposure standards for mercury. He also discussed the calibration of vendor standard generators with respect to the NIST primary standard. Dr. Hodges proposed a high-resolution UV absorption measurement of mercury using cavity ring-down spectroscopy. In summary NIST is working on a traceable standard for precise measuring of mercury in order to facilitate industry compliance with EPA guidelines.
The last talk in the two day incubator was by Robert Wielgosz, from the Bureau International des Poids et Mesures (BIPM). Robert started by drawing the attention of the audience that May 20 is the World Metrology Day (SI system) which can’t make our incubator timing better! Dr. Wielgosz’s talk was about unifying standards across multiple national metrology laboratories. His talk was divided into two main topics. The first is to assess the isotopic variation in CO2 impact on concentration measurement. Also, he discussed the impact of CCQM/BIPM GHG comparison activities. The second topic was towards the next generation of standards for surface ozone measurements and the challenges in ozone measurement in terms of compatibility. Dr. Wielgosz discussed the NIST and BIPM program on ozone standards comparison where they are trying to work on improving performance of ozone standards worldwide. He discussed the importance of precision cross section measurements for ozone in the context of evaluating local compliance with government regulations for allowable concentrations of surface ozone. Finally, Dr. Wielgosz overlaid the challenges of next generation surface ozone standards and sensors in terms of aging of instruments, cost, logistics, opportunities in terms of developing new light sources in UV, and field instrument development based on same platform.
At the end of the meeting Jorge Pezoa gave a summary of the main issues facing researchers working in the design, modeling, and developing of sensors for Precision Measurements in Air Quality & Turbulence. An interesting and vigorous discussion followed the summary comparing the various research paths and hurdles facing the researchers in this field and possible solutions. Most of the attendees agree on the fact that we have a full optical toolbox with which a variety of challenges in GHG and AQ sensing could be performed. However, a broader number of researchers with a more diverse background in sensing-based disciplines needs to be included in future discussions. Future topical meetings in AQ and turbulence should include public policy and public health experts to facilitate potential technology transfer and advance cross-communication and collaboration across scientific disciplines. Distinct measurement challenges related to GHGs and AQ were established. In the former, the measurement of gas flux is important whereas in the later, rapid identification of spikes in specific harmless species, especially aerosols and related particulates, requires a distributed set of low-cost optical and photonic sensors.
The OSA Incubator on Precision Measurements in Air Quality & Turbulence: From Space-based Observations to Networked, Ground-based Point Sensors, 18-20 May 2016 hosted by the leadership of the Environmental Sensing Technical Group: Adam J. Fleisher, National Institute of Standards & Technology, United States; Partha Banerjee, University of Dayton, United States; and Jorge E. Pezoa, Universidad de Concepción, Chile. The meeting successfully brought researchers from industry, military, and national labs working in different application areas but sharing the same goals which are to mitigate, quantify, model, and predict pollution. The researchers also discussed in details the viable and future techniques on how to develop high precision, high sensitivity, low cost, and portable sensors to quantify pollution caused by deteriorating air quality whether from GHGs, wildfires, anthropogenic and natural aerosols, and the myriad particulate air pollutants which drastically have a negative effect on the human well-being and the quality of life.
George Nehmetallah, Cathlolic University of America
