abstract: The occurrence of micro-and nanoplastic (MNP) debris in the environment is a research area of considerable public health concern. Various combinations of methods for extraction, isolation, and quantification of MNP have been applied but literature studies evaluating the appropriateness and efficacy of these protocols are lacking. A meta-analysis of the literature (n=134; years 2010-2017) was conducted to inventory and assess the appropriateness of methodologies employed. Some 30.6% of studies employed visual identification only, which carried a calculated misidentification error of 25.8-74.2%. An additional 6.7% of studies reported counts for particles smaller than the cutoff value of the selected collection pore size, and 9.7% of studies utilized extraction solution densities which exclude some of the polymers commonly occurring in the environments investigated. A composite value of data vulnerability of 43.3% was determined for the sample, indicating considerable weaknesses in the robustness of information available on MNP occurrence and type. Additionally, the oxidizing solutions documented in the literature frequently were deemed unsuccessful in removing interfering organic matter. Whereas nanoplastics measuring <1 µm in diameter are likely principal drivers of health risk, polymer fragments reported on in the literature are much larger, measuring 10+ µm in diameter due to lack of standardized methods. Thus, current inventories of MNP in the environmental MNP feature data quality concerns that should be addressed moving forward by using more robust and standardized techniques for sampling, processing and polymer identification to improve data quality and avoid the risk of misclassification. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2018

<p>  </p> <p>Secondary organic aerosols (SOA) play an important role in the Earth’s radiative budget due to their potential to either warm or cool the atmosphere through light absorption or light scattering, respectively, and to cool or warm the lower atmosphere by acting as cloud condensation nuclei. SOA are air-suspended liquid and semi-solid droplets that form through multiphase chemical processes. Atmospheric photochemical oxidation of volatile organic compounds (VOCs) in the presence of air pollutants, such as NO_x (NO + NO₂) and the OH radical, promote formation of low volatility organic products that eventually condense to form SOA. To better understand the sources and sinks, formation, and fate of SOA, laboratory studies investigating oxidation of a biogenic VOC as well as anthropogenic emissions of SOA precursors were conducted. The first study (<em>Chapter 3</em>) investigated the OH-initiated oxidation of β-ocimene, a biogenic volatile organic compound (BVOC) released from vegetation, including forests, agricultural landscapes, and grasslands emitted during the daytime. The oxidation of BVOCs in the presence of NO_x leads to the formation of functionalized organic nitrate (RONO₂) compounds and isomers that easily condense to form SOA. To understand their atmospheric fate, the RONO₂ hydrolysis rate constants were quantified and found to be highly pH dependent. The findings of this study provide key insights into the formation and fate of organic nitrates and NO_x cycling in forested environments from daytime monoterpenes that were not previously included in atmospheric models. </p> <p>The second study (<em>Chapters 4 and 5</em>) investigated condensed waste emissions generated during Cured-In-Place-Pipe (CIPP) installations. This installation process is the most popular, least expensive, and most frequently used technology that cures leaking sanitary and stormwater sewers. Waste plumes discharged during pipe manufacture are complex multi-phase mixtures of volatile and semi-volatile organic compounds (VOC and SVOC, respectively), primary organic aerosols and SOA, fine debris of partially cured resin, and direct emission of nanoplastic particles that are all blown into the atmospheric environment at significant concentrations at worksites. This work unveiled a direct emission source of airborne nanoplastic particles as well as substantial concentrations of hazardous compounds and SOA precursors that were previously unrecognized. </p>