Collaborative Research: CAS-MNP--Precursors of Long-Distance Aerial Transport of Microplastics from Urban Environments

微塑料（MP）是尺寸小于5 mm的塑料颗粒，已在水性环境中研究了15年以上。这些研究提高了公众对MP对水生生态系统（特别是鱼类及其食物网）的不利影响的认识，许多国家开始限制塑料的使用和处置。海洋被视为最终汇的MP，其中MP被认为是主要通过水生环境（径流到小溪，河流，溪流，或污水排放等）。越来越多的证据表明，MP存在于许多被认为是原始的陆地系统中。然而，只有关于长距离大气迁移（100公里）和沉积的推测被用来解释它们在这些区域的存在。这些发现引起了人们对MP逃离其主要来源并进行长距离空中旅行的机制的兴趣。由于人类活动产生的物质导致了MP的形成，城市被认为是MP的主要来源。该项目的重点是了解MP从城市来源运输到大气中的主要过程和机制。该项目将为政策制定者和生态毒理学家提供必要的调查结果，这些政策制定者和生态毒理学家关注是否以及如何根据使用塑料的行业的快速扩张对MP进行监管。面临的令人生畏的科学挑战是空气流动的复杂性和城市环境中MP类型的可变释放，城市冠层（街道，建筑物等）之间的相互作用。以及MP的沉积/逸出、MP颗粒特性和天气条件。为了解决项目的总体目标，提出了3个相互关联的科学问题：Q1与城市排放源相关的MP如何被运输出城市系统？（任务1-3）; Q2城市地表形态的不同特征（例如，高密度城市中心与低密度居民区）如何与MP源/汇分布（街道网络）的空间配置相互作用，以影响其传输和沉积？(Task问题3如何量化MP成为空气传播的机会与城市表面形态和天气模式的关系？(Task 5）。科学计算机模拟运行和MP轨迹跟踪模型将被连接并用于解决Q1-Q3。将系统地探索表征城市的城市形态特性和MP的物理化学特性，以揭示形态、MP特性、天气模式和MP出城运输之间的联系。机器学习等数据驱动的方法也将应用于模拟结果，以制定未来可用于MP法规的模型。 该项目探讨了一项新的外联活动，利用非营利组织“维基教育”的资源。维基教育专门培训学生编辑维基百科上的信息，同时提供当今和可预见的未来社会面临的问题的高质量信息。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Micro-plastics (MPs), which are plastic particles of sizes smaller than 5 mm, have been studied in aqueous environments for more than 15 years. These studies have raised public awareness about the adverse effects of MPs on aquatic ecosystems (fish in particular and their food-web in general) and many countries are beginning to limit the use and disposal of plastics because of them. Oceans are viewed as the ultimate sink of MPs, where MPs are assumed to be transported primarily via aquatic environments (runoff to creeks, rivers, streams, or sewage discharge, etc.). There is mounting evidence that MPs are present in many terrestrial systems that are presumed to be pristine. However, only speculation about long-distance atmospheric transport ( 100 km) and deposition has been offered to explain their presence in these regions. Such findings are prompting interest in the mechanisms by which MPs escape from their main source and travel long-distance aerially. Because of human activities that produce materials that lead to the formation of MPs, cities are considered major sources of MPs. This project is centered on understanding the primary processes and mechanisms in which MPs are transported from urban sources to the atmosphere. The project will lead to findings necessary for policy makers and eco-toxicologists concerned with whether and how MPs should be regulated in light of the rapid expansion in industries that use plastics. Daunting scientific challenges to be confronted are the complexity of air flow and variable releases of MP types in urban settings, the interaction between urban canopy (streets, buildings, etc.) and deposition/escape of MPs, the MP particulate properties, and weather conditions. To address the overall project goal, 3 inter-related science questions are proposed: Q1 How MPs associated with urban emission sources get transported out of an urban system? (Tasks 1-3); Q2 How do different characteristics of urban surface morphology (e.g. high-density urban center versus low-density residential areas) interact with the spatial configurations of MP source/sink distributions (street network) to impact their transport and deposition? (Task 4), and Q3 How to quantify the chance of MPs becoming air-borne in relation to urban surface morphology and weather patterns? (Task 5). The state-of-the science computer simulation runs and MP trajectory tracking models will be interfaced and used to address Q1-Q3. The urban morphological properties characterizing cities and the physical-chemical properties of MPs will be systematically explored to unpack connections between morphology, MP property, weather patterns and the transport of MPs out of cities. Data-driven approaches such as machine-learning will also be applied to simulation results to enable formulation of models that can be used for MP regulations in the future. The project explores a new outreach activity that leverages resources of a non-profit organization `Wiki Education'. Wiki Education specializes in training students to edit information in Wikipedia while providing high-quality information on issues confronting society today and in the foreseeable future.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.