UC San Diego

Marine aerosols play a large role in the Earth’s climate by cooling via interaction with energy from the sun and altering the chemical and physical properties of clouds. The dissolved organic matter at the ocean surface, where sea spray aerosols and marine gases can be generated, is formed by the microbial loop by circulating nutrients and the ingestion of organisms like phytoplankton or bacteria – with additional inputs from terrestrial sources. The colored fraction of this organic matter, known as marine chromophoric dissolved organic matter, is a subject of considerable interest due to its ability to photosensitize nearby molecules. This indirect photochemical mechanism in the marine environment is not well understood. This dissertation first investigates the composition and properties of this fraction by conducting both simple model experiments in the laboratory and larger experiments such as the use of an indoor ocean-atmosphere facility. The ability to bridge the gap between these two types of study provides this thesis an excellent opportunity to answer various questions regarding the importance of understanding the role of heterogeneous chemistry and photochemistry in our surrounding environment. Lastly, this dissertation applies a similar perspective on photochemistry to explore the multiphase chemistry relevant to indoor environments. Humans spend 20 hours a day on average inside buildings, and while atmospheric pollution has been thoroughly studied, the pollution indoors is widely unknown and unregulated. Inspired by experiments conducted in a real home, various experimental model systems were investigated regarding indoor surfaces. The ultimate goal of the thesis being, to provide insight into the many vital heterogeneous and multiphase processes currently undiscovered in environmental chemistry community.