Biological discharge

Measurement of BVOC fluxes

The majority of volatile organic compounds (VOCs) in the atmosphere originate from biological emissions, known as BVOCs. They play a crucial role in atmospheric chemistry and are linked to ozone formation and the formation of secondary aerosols (SOA) .

In the past, studies of atmospheric–ecosystem exchange of BVOCs were limited to a small number of key compounds. The high temporal resolution of the ProC-TOF online mass spectrometer enables eddy covariance measurements to investigate active atmospheric–ecosystem exchange of a large number of BVOCs, providing new insights into the understanding of atmospheric VOC budgets.

The eddy covariance (also known as eddy correlation and eddy) technique is a key method for measuring and calculating vertical atmospheric turbulence fluxes. It requires high-temporal-resolution measurements of 3D wind components (e.g. 5–20 Hz). Parallel measurements of VOC concentrations can be correlated with vertical wind components to extract emission and deposition fluxes. This requires a trace gas analyser capable of quantitatively measuring ultra-low VOC concentrations with a high temporal resolution of 10 Hz.

The ProC-TOF MS series perfectly meets these requirements for eddy covariance flux measurements. They enable high-temporal-resolution measurements, and their high sensitivity to VOCs provides quantitative results for trace gas concentrations. PTR-TOF instruments acquire the full spectrum in every measurement, whilst collecting a wealth of data on existing BVOCs . Furthermore, their high mass resolution allows for the separation of isobaric lines and provides chemical identification of the compounds under investigation.

ProC-TOF online mass spectrometers are ideally suited for the sensitive measurement of biogenic VOCs, including hydrocarbons (isoprene, monoterpenes and sesquiterpenes) and oxygenated organic compounds (e.g. methanol, acetone, acetic acid, hexenal), as well as previously unknown compounds.