Measurement of Formaldehyde by Laser Induced Fluorescence Spectroscopy
Abstract
Gas phase formaldehyde (HCHO) is a key species in the troposphere. It is formed as an intermediate product during the removal of almost all volatile organic compounds (VOCs) by the hydroxyl radical (OH) and is a tracer of overall oxidising capacity. A new instrument has been developed for the measurement of [HCHO] by laser induced fluorescence (LIF) spectroscopy and deployed in the field. Ultra-violet (UV) radiation from a tuneable fibre laser was used to excite HCHO in a low pressure cell (~130 Torr) at ca. 353 nm with fluorescence collected between 390 - 550 nm. The resulting fluorescence was detected by a photomultiplier tube (PMT) and processed by photon counting techniques. The instrument performance will be described in detail in addition to a novel calibration method where a known quantity of HCHO was produced through photolysis of methanol (CH3OH) vapour in the presence of oxygen. The instrument was first deployed in June 2014 at a suburban site in York (UK). Data from this campaign and interpretation will be presented in addition to observations from more recent field measurements.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2014
- Bibcode:
- 2014AGUFM.A23E3290C
- Keywords:
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- 0399 General or miscellaneous