A high-frequency response relaxed eddy accumulation flux measurement system for sampling short-lived biogenic volatile organic compounds

Authors

  • Robert R. Arnts,

    Corresponding author
    1. National Exposure Research Laboratory, Human Exposure and Atmospheric Sciences Division, US EPA, Research Triangle Park, North Carolina, USA
    • Corresponding author: R. R. Arnts, National Exposure Research Laboratory, Human Exposure and Atmospheric Sciences Division, US EPA, 109 T W Alexander Drive, Mail Drop E205-03, Research Triangle Park, NC 27711, USA. (rrarnts@gmail.com)

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  • Fred L. Mowry,

    1. Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina, USA
    2. National Risk Management Research Laboratory, Air Pollution Prevention Control Division, US EPA, Research Triangle Park, North Carolina, USA
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  • Gary A. Hampton

    1. Hampton Technologies Inc., Longmont, Colorado, USA
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Abstract

[1] A second-generation relaxed eddy accumulation system was built and tested with the capability to measure vertical biogenic volatile organic compound (VOC) fluxes at levels as low as 10 µg C m−2 hr−1. The system features a continuous, integrated gas-phase ozone removal procedure to allow for the measurement of highly reactive species such as β-caryophyllene and polar terpenoids such as linalool. A two-component internal standard continuously added to the accumulators was used to correct for switching-induced volumetric errors and as a check on VOC losses exceeding accumulator tube adsorption limits. In addition, the internal standards were used to demonstrate that accumulators quickly return to target flow rates at segregation valve switching frequencies up to at least 0.8 Hz. The system was able to measure daytime hourly fluxes of individual biogenic VOC including oxygenated terpenoids, monoterpenes, and sesquiterpenes.

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