Multiphase Chemistry of Air Pollutants from Urban Cured-In-Place-Pipes Installations: Unrecognized Source of Atmospheric Micro- and Nano-Plastics

空气污染是一个全国性和全球性的问题，对人类的健康和福祉具有重大的不利影响。在全国范围内，人们越来越关注城市CIPP(就地固化管道)装置排放的气体和颗粒物空气污染物。CIPP工艺被广泛用于修复城市地区泄漏的卫生和雨水管道。最近的研究表明，CIPP的排放是由气体和液体有机污染物的复杂混合物组成的，其中含有大量的微米和纳米塑料颗粒(MNPs)。由于它们的低降解率和在环境介质(土壤、水和空气)中的持久性，MNPs对生态系统构成了长期威胁。MNPs也很容易通过摄入和吸入传播到人体内，对公众健康构成潜在威胁。该项目的目标是调查城市CIPP排放的化学成分，重点是二次形成和直接排放的空气中的MNPs。该项目的成功完成将通过产生新的基本知识造福社会，这些知识可以为CIPP设施的设计和运行提供信息，以控制、减少和最大限度地减少MNPs的形成和释放。学生教育和培训将进一步造福社会，包括对两名博士生的指导。尽管人们越来越关注CIPP装置造成的城市空气污染，但对CIPP排放的MNPs的多相化学、反应性和环境/健康影响的基本理解仍然难以捉摸。这项研究的目的是表征城市CIPP排放的组成和多相物理化学。为了推进这一目标，PI建议将现场采样、实验室实验和高级分析表征相结合。首先，PI建议将具有代表性的和模拟的CIPP排放的实验室和现场样品分成三个组分：1)可溶于水和溶剂的有机组分，2)干燥(冻干)胶体，3)单个胶体颗粒。对于CIPP可溶有机组分的表征，PI建议结合使用软电离源[即电喷雾电离(ESI)和常压光化学电离(APPI/APCI)]的高效液相色谱(HPLC)和高分辨率质谱学(HRMS)，以获得CIPP排放中可能存在的极性和非极性有机化合物的广泛描述。对于干燥(冻干)的CIPP胶体部分，PI建议结合颗粒流式细胞仪和动态光散射来表征其颗粒尺寸分布。最后，PI建议将拉曼显微镜、扫描电子显微镜(带EDX)和同步辐射扫描透射式X射线显微镜(STXM)与近边X射线吸收精细结构(NEXAFS)相结合，以成像和分析干燥(冻干)的CIPP胶体部分中存在的单个粒子(例如，MNPs)的组成。这项拟议研究的成功完成可能导致对CIPP排放的MNPs和气体/液体有机污染物的全面表征，最终提供新的基础知识来指导CIPP设施的设计和运营，以控制、减少和最小化城市空气污染。该奖项由NSF/ENG/CBET部门的环境工程计划和NSF/MPS/CHE部门的环境化学计划共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Air pollution is a national and global problem with significant adverse impact on human health and wellbeing. Nationwide, there is a growing concern about the emissions of gaseous and particulate air pollutants from urban CIPP (Cured-in-Places-Pipes) installations. The CIPP process is widely utilized to repair leaking sanitary and storm sewer pipes in urban areas. Recent studies have shown that CIPP emissions consist of complex mixtures of gaseous and liquid organic pollutants containing significant amounts of micro- and nano-plastic particles (MNPs). Because of their low degradation rates and persistence in environmental media (soils, water and air), MNPs pose long-term threats to ecosystems. MNPs are also easily transferred to human bodies through ingestion and inhalation, posing a potential threat to public health. The goal of this project is to investigate the chemical composition of urban CIPP emissions with a focus on the secondary-formed and directly emitted airborne MNPs. The successful completion of this project will benefit society through the generation of new fundamental knowledge that could inform the design and operations of CIPP installations to control, reduce and minimize the formation and release of MNPs. Further benefits to society will be achieved through student education and training including the mentoring of two doctoral students.Despite the growing concern about urban air pollution from CIPP installations, a fundamental understanding of the multiphase chemistry, reactivity, and environmental/health impacts of MNPs from CIPP emissions has remained elusive. The goal of this research is to characterize the composition and multiphase physical chemistry of urban CIPP emissions. To advance this goal, the PI proposes to combine field sampling, laboratory experiments and advanced analytical characterization. First, the PI proposes to fractionate laboratory and field samples from representative and simulated CIPP emissions into three fractions: 1) water- and solvent-soluble organic fractions, 2) dried (lyophilized) colloids, and 3) individual colloidal particles. For the characterization of the CIPP soluble organic fractions, the PI proposes to combine high performance liquid chromatography (HPLC) and high-resolution mass spectrometry (HRMS) interfaced with soft ionization sources [i.e., electrospray ionization (ESI) and atmospheric pressure photo-chemical ionization (APPI/APCI)] to obtain a broad account of the polar and nonpolar organic compounds that might be present in CIPP emissions. For the dried (lyophilized) CIPP colloidal fractions, the PI proposes to combine particle flow cytometry with dynamic light scattering to characterize their particle size distributions. Finally, the PI proposes to combine Raman microscopy, SEM (with EDX), and synchrotron-based scanning transmission X-ray microscopy (STXM) complemented by near edge X-ray absorption fine Structure (NEXAFS) to image and analyze the composition of the individual particles (e.g., MNPs) present in the dried (lyophilized) CIPP colloidal fractions. The successful completion of the proposed research could lead to a comprehensive characterization of MNPs and gaseous/liquid organic pollutants from CIPP emissions ultimately providing new fundamental knowledge to guide the design and operations of CIPP installations to control, reduce and minimize urban air pollution.This award is jointly funded by the Environmental Engineering program of the NSF/ENG/CBET Division and the Environmental Chemical Sciences program of the NSF/MPS/CHE Division.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.