CAREER: Micro- and Nanoplastics in Sea Spray: Emission, Transport, and Deposition in the Environment

微塑料和纳米塑料已成为世界范围内普遍存在的污染物。几乎在所有生态系统和环境介质中都发现了MNPs。它们很容易被生物体吸收，并在进入食物链时对人类和生态系统的健康构成新的风险。每年有数百万吨的MNPs被释放到海洋中。最近，在海洋大气边界层的空气样本中检测到塑料颗粒。然而，人们对控制海洋微粒从海洋向大气和其他环境区隔和介质释放和转移的过程和机制知之甚少。这个CAREER项目将解决这些关键的知识缺口。具体而言，本课题拟开展综合实验与模拟项目，验证以下假设：1)海洋微粒子可通过海浪破碎和气泡破裂等方式被海洋微粒子雾化并转移到大气中；2)海洋微粒子通过海洋微粒子的大小、形状、年龄和成分对其雾化进行调节；3)海雾MNPs可以通过远距离大气输送和沉积转移到其他环境隔间和介质中。该项目的成功完成将通过产生新的数据和知识来促进对大气中海洋悬浮微粒在环境中的释放、运输和沉积的基本认识和量化，从而造福社会。进一步的社会效益将通过学生教育和培训来实现，包括在弗吉尼亚理工大学指导两名研究生和两名本科生。一个广泛持有的假设是，海洋充当微纳米塑料（MNPs）的准永久水槽；也就是说，进入海洋的塑料颗粒将在那里停留很长一段时间。然而，在海洋大气边界层的空气样本中检测到MNPs表明，从海洋和海洋到大气的颗粒转移可能是塑料环境运输和污染的重要途径，但尚未得到充分解释。CAREER项目的总体目标是调查和量化海洋悬浮微粒通过海洋喷雾的雾化，以及它们在大气中的运输、沉积和积累。为了实现这一目标，首席研究员（PI）提出围绕四个研究任务开展综合实验和建模计划。任务1将研究在一个特别设计的气溶胶发生器槽中产生的海洋喷雾MNPs，以模拟通过海洋/海浪破碎和气泡破裂形成的颗粒，使用特征良好的塑料颗粒作为模型系统。任务2将评估和量化雾化的MNPs通量与颗粒大小、形状、年龄和组成之间的关系。任务3将结合任务1和任务2中生成的数据，开发一个过程模型并将其参数化，该模型可用于估算海喷MNP气溶胶的表面通量。任务4将把任务3的MNP表面通量模型整合到社区多尺度空气质量（CMAQ）模型中，模拟和量化海雾MNP气溶胶在相关环境隔间和介质中的运输和沉积。该项目的成功完成将产生新的基础知识、数据和建模工具，以量化海洋悬浮微粒的产生及其随后在环境中的运输、沉积和积累，从而产生变革性的影响。为了实现这个CAREER项目的教育和培训目标，PI将与西弗吉尼亚州科学博物馆合作，利用PI的气溶胶产生罐的展览版本，通过动手实验来演示海洋喷雾气溶胶和海洋大气MNPs的形成。此外，PI计划与弗吉尼亚理工大学的工程多样性增强中心（CEED）合作，为在STEM领域代表性不足的大学预科学生开发一个夏令营培训模块。提议的夏令营模块将包括一个动手实验，在此期间，学生将学习如何表征雾化MNPs从PI的实验室使用光学显微镜和相关的图像处理技术。该奖项反映了美国国家科学基金会的法定使命，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- and nanoplastics (MNPs) have become pervasive pollutants throughout the world. MNPs have been found virtually in all ecosystems and environmental media. They can be easily ingested by living organisms and pose new risks to human and ecosystem health as they enter the food chain. Every year millions of tons of MNPs are released into oceans and seas. Recently, plastic particles were detected in air samples from marine atmosphere boundary layers. However, little is known about the processes and mechanisms that control the release and transfer of MNPs from oceans and seas to the atmosphere and other environmental compartments and media. This CAREER project will address these critical knowledge gaps. More specifically, the Principal Investigator proposes to carry out an integrated experimental and modeling project to test the hypotheses that 1) MNPs can be aerosolized and transferred to the atmosphere by sea spray through ocean/sea wave breaking and bubble bursting, 2) the aerosolization of MNP particles via sea spray is modulated by their size, shape, age, and composition, and 3) sea spray MNPs can be transferred to other environmental compartments and media through long-range atmospheric transport and deposition. The successful completion of this project will benefit society through the generation of new data and knowledge to advance the fundamental understanding and quantification of the atmospheric release, transport, and deposition of sea spray MNPs in the environment. Further benefits to society will be achieved through student education and training including the mentoring of two graduate students and two undergraduate students at Virginia Tech.A widely held assumption is that oceans and seas act as quasi-permanent sinks for micro-nanoplastics (MNPs); that is plastic particles which enter oceans and seas will remain there for extended periods. However, the detection of MNPs in air samples from marine atmosphere boundary layers suggests that particle transfer from oceans and seas to the atmosphere might be an important and yet poorly accounted pathway for plastic environmental transport and pollution. The overarching goal of this CAREER project is to investigate and quantify the aerosolization of MNPs via sea spray and their atmospheric transport, deposition, and accumulation in the environment. To advance this goal, the Principal Investigator (PI) proposes to carry out an integrated experimental and modeling program organized around four research tasks. Task 1 will investigate the generation of sea spray MNPs in a specially designed aerosol generator tank to simulate particle formation via ocean/sea wave breaking and bubble bursting using well characterized plastic particles as model systems. Task 2 will evaluate and quantify the relationships between the flux of aerosolized MNPs and particle size, shape, age, and composition. Task 3 will combine the data generated in Tasks 1 and 2 to develop and parameterize a process model that could be used to estimate the surface flux of sea spray MNP aerosols. Task 4 will integrate the MNP surface flux model from Task 3 into the Community Multiscale Air Quality (CMAQ) model to simulate and quantify the transport and deposition of sea spray MNP aerosols in relevant environmental compartments and media. The successful completion of this project has the potential for transformative impact through the generation of new fundamental knowledge, data, and modeling tools to quantify the generation of sea spray MNP aerosols and their subsequent transport, deposition, and accumulation in the environment. To implement the education and training goals of this CAREER project, the PI will work with the Science Museum of Western Virginia to create a public exhibit with hand-on experiments to demonstrate the formation of sea spray aerosols and marine atmospheric MNPs using an exhibit version of the PI’s aerosol generation tank. In addition, the PI plans to partner with the Center for Enhancement of Engineering Diversity (CEED) at Virgina Tech to develop a training module for summer camps for pre-college students who are underrepresented in STEM. The proposed summer camp module will include a hands-on experiment during which the students will learn how to characterize aerosolized MNPs from the PI’s lab using optical microscopy and related image processing techniques.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.