Characterisation of a chemiluminescence ozone monitor for volcanic applications

Volcanic plumes are known to contain reactive halogen species, especially bromine monoxide, which are known to efficiently catalyse ozone (O3) destruction. Therefore, local O3 depletion is expected inside volcanic plumes, which has been measured in several field studies and is also found in several modelling studies. Recently, in order to quantify O3 mixing ratios in volcanic plumes, mainly UV absorption monitors have been used as these have become the standard technique for ambient O3 monitoring. However, these instruments show a large positive interference with sulfur dioxide (SO2), which is difficult to correct. This poses a significant problem for volcanic measurements since SO2 mixing ratios can exceed O3 mixing ratios by factors of 1000 or more. This interference problem can be solved by using the 'antiquated' technique of chemiluminescence (CL) O3 monitors since these devices have been shown to exhibit no interference from trace gases contained in volcanic plumes - in particular SO2. In this thesis, a compact and mobile (backpack-size, 10kg) CL monitor is introduced and characterised. The results of O3 measurements in ambient air and inside the plume emanating from a fumarole at the summit of Mt. Etna volcano, Italy with the CL monitor are compared to those of a conventional UV absorption monitor. In this first field study inside a fumarole, no significant interference with volcanic SO2 concentrations for the CL monitor was observed. Additionally, a rough calculation to estimate the expected O3 depletion in volcanic plumes was made. Contrary to popular belief, this calculation suggests no significant reactive halogen catalysed O3 loss (i.e. ca. 1%) in volcanic plumes for typical bromine monoxide concentrations.

Level thesis:degree_level

master

Grantor dc:publisher

Universität Heidelberg

Year

2021

Author dc:creator

• Rüth, Maja Isabelle

Contributors dc:contributor

• Platt, Ulrich

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/29947

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:29947