Browsing by Subject "Vocus"
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(2024)Volatile Organic Compounds are chemicals which get released as gasses and can have a variety of effects on the environment, climate change, and air quality. Capable of being transported across long distances, VOCs can contribute to the formation and concentration of ozone, formation of secondary organic aerosol, and affect Earth's radiative balance. Coastal waters emit high amounts of VOCs into the atmosphere. While there is a body of research on VOCs emitted from terrestrial sources, such as forests, the impact of VOCs emitted from coastal sea areas on sea-atmosphere interactions is less understood. This study examined VOC signals at a coastal site on the Baltic Sea by deploying a Vocus Proton Transfer Reaction Time-of-Flight Mass Spectrometer measuring ambient VOCs in air from June-August 2023. In this study, the Vocus PTR-TOF-MS was able to provide informative data to improve our understanding of the behavior of VOCs at this Baltic Sea coastal site. From a snapshot analysis of July 17-24 2023, isoprene, monoterpenes, dimethylsulfide, jasmonic acid, and benzoquinone are speculated to potentially have marine signatures, but could be coming from different marine sources or different biological species in the Baltic Sea. The behavior of the VOC signals and their detection is speculated to be related to wind speed and wind direction. Meteorological factors can impact what VOC signals get detected by the Vocus by affecting how air masses get mixed and transported to the instrument. By deploying the relatively new Vocus PTR-TOF-MS in a new location, this study helps to improve our knowledge of the behavior of VOCs at this Baltic Sea coastal site and how the ecology of the Baltic Sea interacts with the atmosphere.
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(2020)Biogenic Volatile Organic Compounds play a major role in the atmosphere by acting as precursors in the formation of secondary organic aerosols and by also affecting the concentration of ozone. The chemical diversity of BVOCs is vast but global emissions are dominated by isoprene and monoterpenes. The emissions of BVOCs from plants are affected by environmental parameters with temperature and light having significant impacts on the emissions. The Downy birch and Norway spruce trees consist of heavy and low volatile compounds but published results are limited up to observing sesquiterpenoid emissions from these two trees. In this study, the Vocus proton-transfer-reaction time-of-flight mass spectrometer is deployed in the field to examine BVOC emissions from Downy birch and Norway spruce trees. With higher mass resolution, shorter time response and lower limits of detection than conventional PTR instruments, the Vocus can effectively measure a broader range of VOCs. For the first time, real-time emissions of diterpenes and 12 different oxygenated compounds were observed from birch and spruce trees. The emission spectrum of birch was dominated by C10H17+, while for spruce C5H9+ contributed the most. The sum emissions of oxygenated compounds contributed significantly to the observed total emissions from both the trees. The emission rates of all compounds varied dramatically throughout the period due to fluctuations in temperature and light. Due to lack of data from spruce, conclusive results for temperature and light response on terpene emissions could not be drawn. For birch, the emission rates were well explained by the temperature and temperature-light algorithms. The terpene emissions modelled using both algorithms correlated similarly with experimental data making it difficult to decisively conclude if the emissions originated from synthesis or pools.
Now showing items 1-2 of 2