Tjarda is originally from the north of England. She obtained a Master of Science from the University of Cambridge in 2003. Then, always attracted by the border areas located at the crossroads of different fields of physics, she left for Svalbard (Norwegian archipelago located at 78 ° North latitude. ) at UNIS for practical training in Arctic geosciences. At the end of her studies, she specialized in atmospheric chemistry and volcanology. Back at Cambridge University, in 2009 she defended a doctoral thesis on the atmospheric chemistry of volcanic emissions and more particularly the chemistry of halogens that volcanoes emit in large quantities. It had been discovered that these halogens were not simply leached into the atmosphere, as previously thought, but that they could be transformed into reactive forms. To study this phenomenon, Tjarda developed instruments with miniature gas sensors to measure emissions and created a digital model of the chemistry of the volcanic plume. His model predicted that the halogenated chemistry of the volcanic plume could be the cause of ozone destruction downstream from the volcano. A year later, while Tjarda was in Norway as a post-doctoral fellow and guest lecturer working on arctic pollution, this prediction was confirmed by airborne measurements taken during the Icelandic volcano Eyjafjallajökull eruption in 2010. It was not until 2012, as part of a post-doctorate in Orléans at LPC2E funded by the LabEx Voltaire, that Tjarda had the opportunity to refocus his research on volcanic halogens. In coordination with her colleagues from Orleans, the industrial partner Alphasense and other national and international partners, she is resuming her studies on the modeling and measurement of volcanic emissions. In this context, she then worked, on the one hand, on the characterization of the role of volcanic aerosols whose surface catalyzes halogen reactions and, on the other hand, on the quantification of the impact of volcanic halogens on the atmospheric composition at a regional scale. Following her results, Tjarda obtained a position as CNRS researcher in 2016. Two years later, in 2018, she obtained ANR funding for an interdisciplinary consortium bringing together five laboratories (LPC2E, ISTO, LATMOS, CNRM,