Panji, Namrata Shanmukh2024-08-242024-08-242024-08-23vt_gsexam:41293https://hdl.handle.net/10919/121003Biogenic volatile organic compounds (BVOCs) are naturally occurring organic compounds emitted by plants, trees, and ecosystems, exerting a profound influence on the Earth's atmosphere, air quality, climate, and ecosystem dynamics. This research project aims to advance our understanding of BVOC emissions and their implications through a comprehensive and multi-faceted investigation. We investigate the dynamics of BVOCs in the atmosphere through three key objectives. First, we introduce a novel enriching inlet that uses selective permeation to preconcentrate reactive organic gases in small sample flows for atmospheric gas sampling, enhancing the sensitivity and detection limits of analytical instruments. Enrichments between 4640% and 111% were measured for major reactive atmospheric gases at ultra low flow rates and roughly several hundred percent for ambient samples at moderately low flow rates. Second, we constrain light-dependency in BVOC emissions models by comparing modeled and long-term observed BVOC concentrations measured at a mid-canopy monitoring site in a southeastern US forest. The Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the Framework for 0-D Atmospheric Modeling (F0AM) were utilized to simulate emissions and chemical transformations, respectively to disentangle the time- and species-specificity of light dependency for various BVOC (α-pinene, camphene, and α-fenchene are completely light-independent and limonene, β-thujene, sabinene, and γ-terpinene are seasonally light-dependent). Finally, we examine these models deeper to investigate uncertainties and highlight current limitations due to variability in planetary boundary layer height (PBLH) datasets. We highlight the significance of simultaneous PBLH and BVOC measurements for improving the accuracy of BVOC concentration models. We show that a lack of co-located measurements is a large source of uncertainty in modeling BVOC concentrations. The successful completion of these objectives contributes to a better understanding of the complex interactions between BVOC emissions and atmospheric chemistry.ETDenIn Copyrightbiogenic volatile organic compoundspreconcentrating inletemissions modelinglight dependent fractionplanetary boundary layer heightDissertation