Fossil fuel-derived materials are readily incorporated into the built environment without much knowledge about how they can impact the long-term well-being of natural ecosystems and public health. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has allowed for the molecular characterization of complex fossil fuel-derived materials, such as crude oil and asphalt binder, and their photoproducts that are produced as a result of exposure to weathering processes (id est solar irradiation). Photooxidation from sunlight has been identified as the primary phototransformation process responsible for the transformation of fossil fuel-derived materials in the environment. As photooxidation affects these materials, the generation of newly formed oil- and water-soluble compounds becomes a concern and new evidence points to the consideration of these materials as emerging environmental contaminants. Thus, it is important that knowledge regarding the molecular composition, structure, and subsequent behavior of fossil fuel-based photoproducts is acquired as it is valuable in understanding the long-term effects that occur from the use of materials such as crude oil, asphalt binder, and pavement sealant. Specifically, much remains unknown regarding the toxicity of water-soluble photoproducts from fossil fuel-derived materials that can contaminate waterways after introduction to the environment. It is essential that the effects of these potentially toxic compounds in the built environment are understood to combat their effects on the ecosystem, wildlife, and human health.Chapter 1 provides an introductory overview on FT-ICR MS and how it has been used to provide relatively comprehensive molecular profiles for complex unweathered and weathered petroleum-derived materials. Chapter 2 describes the work done to characterize photochemically produced asphaltenes (PPA), a newly formed oil-soluble fraction of crude oil. PPA are of interest as they can persist in the environment due to their inability to degrade over time. Chapter 3 explores an emerging contaminant of great concern, coal tar pavement sealant. This work seeks to provide a relatively comprehensive understanding of petroleum-derived and coal tar-derived sealants and compares how they are transformed after photooxidation which includes molecular characterization, dissolved organic carbon production, and toxicity analysis. Chapter 4 continues to explore coal tar pavement sealant and compares it to another road paving material, asphalt binder. This work focuses on the solubility fractions, maltenes and asphaltenes, from asphalt binder and coal tar sealant and determines their contributions to the production of water-soluble photoproducts. Lastly, Chapter 5 focuses on the potentially harmful water-soluble photoproducts generated from asphalt binder and coal tar sealant that are introduced in Chapters 3 and 4 and seeks to determine their structural profiles by MS/MS techniques. This work also proposes and discusses photochemical pathways that result in the production of different types of water-soluble compounds. This work is of great importance since structural motifs contained in water-soluble photoproducts from fossil-fuel derived materials have yet to be explored. Collectively, this work aims to demonstrate the consideration of fossil fuel-derived oil- and water-soluble photoproducts as emerging environmental contaminants due to their molecular and structural compositions.