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

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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.