Per- and polyfluoroalkyl substances (PFASs) are a class of anthropogenic chemicals that are ubiquitous and can adversely impact environmental and human health. PFASs are thermally and chemically stable and possess simultaneous oil and water repellency, leading to their use in numerous industrial and commercial applications. Consequently, PFASs are found in multiple environmental matrices, with PFAS exposure through drinking water of particular concern for public health. A number of analytical techniques exist to measure PFASs in aqueous matrices, however they have limitations and only measure a small fraction of PFASs. Semiconductor fabrication facilities (fabs) are potentially important, yet understudied, sources of PFASs to the environment. Photolithography is a vital process in semiconductor manufacturing and PFASs are known constituents of photolithography materials. Although knowledge exists on the types of PFASs used in photolithography materials, the exact identity of these compounds are largely unknown because they are proprietary information of the manufacturers. Additionally, some organofluorine-containing compounds are likely to transform during photolithography, yet their transformation products are unknown. The overarching goals of this dissertation were to: (1) improve our understanding of the occurrence of PFASs in fab wastewater; (2) develop a novel analytical method to comprehensively characterize PFASs in aqueous matrices; and (3) identify the sources of and mechanisms by which PFASs are transformed during photolithography. I designed three research projects to address these goals. First, I explored the types of PFASs present in fab wastewater by conducting complementary target and nontarget analyses. I designed a novel semi-quantification method to quantify and identify unknown PFASs. Second, I developed a novel online solid-phase extraction, high-performance liquid chromatography, and electrospray ionization high-resolution mass spectrometry method to quantify short- and ultrashort-chain PFASs in a variety of natural, engineered, industrial, and commercial water systems. Finally, I explored the occurrence of PFASs in photolithography materials and their evolution during simulated photolithography experiments to gain a better understanding of their behavior during photolithography. The results of this dissertation contribute to our knowledge of the quantities and types of PFASs emitted from the semiconductor industry, offering researchers a better understanding of the environmental impacts of this industry.