INTERACTIONS ACROSS BIOSPHERE AND ATMOSPHERE SYSTEMS: EMISSIONS OF TERPENES AND IMPACT ON AIR QUALITY AND CLIMATE

Biosphere–atmosphere interaction, transport energy and matter underlays various biological, physical and chemical processes. Biogenic Volatile Organic Compounds (BVOCs) are highly involved in these processes and have significant effects not only within vegetation and organisms but also in the atmosphere at different spatiotemporal scales, mainly during heat waves and in densely populated areas. Currently, there is an ongoing global health threat due to the air we inhale both in indoor and outdoor environments, as well as a health crisis following the COVID-19 pandemic. The current European Union (EU) policy and World Health Organization (WHO) significantly contributed to our understanding of urban air quality and human health from air pollutants. Monoterpenes, the second major family of BVOCs, are considered important sources of ozone formation and Secondary Organic Aerosols. Their removal in the atmosphere through chemical processes leads to the formation of oxygenated compounds as first-generation Terpene Oxidation Products (TOPs). These compounds emitted by natural sources like plants and conifers have been detected in the atmosphere during observation campaigns. Hence, this project concerns the study of pollution by terpenes emitted from plants and trees and its consequences on the quality of the air we breathe, and its contribution to the global climate. We have chosen α and β-pinene-emitted first-generation products such as Nopinone (C₉H₁₄O), Limona ketone (C₉H₁₄O) and Myrtenal (C₁₀H₁₄O). The absolute rate coefficient was measured for the first time using a cryogenically cooled cell along with the pulsed laser photolysis–laser-induced fluorescence technique for OH radical. The hydrogen abstraction and OH addition pathways were found by using density functional theory method to determine the most favourable position. Our obtained results confirmed that these processes are of high interest for the Earth system scientific community and should be taken into account in Climate Models and Earth System Models.