Hosein Foroutan receives NSF CAREER Award to understand how plastic particles are aerosolized

With summer underway, many people will head to beaches to play in the ocean and listen to the relaxing sound of waves crashing. However, the same rhythmic water movement that helps some beach-goers ease their minds might also be contributing to a worrisome human health risk: the aerosolization of tiny micro- and nano-plastics (MNPs).

Hosein Foroutan, an assistant professor in the Charles E. Via Jr. Department of Civil and Environmental Engineering, has received a National Science Foundation Faculty Early Career Development (CAREER) award to investigate air-sea interaction as a source of atmospheric MNPs.

MNPs are tiny plastic fragments and fibers that have been found in virtually all ecosystems, including land, oceans, rivers, lakes, and even sea ice.  According to Foroutan, they can be easily ingested or inhaled by living organisms, causing inflammation and damage to cells. They pose a major challenge to environmental management as they are difficult to detect, collect, and recycle.

“Microplastics are one of the most pressing environmental issues of our time,” Foroutan said. “Numerous studies have highlighted the adverse impact of microplastics on human and ecological health, with recent research reporting the presence of microplastics deep in human lung and blood.” The danger of MNPs is compounded by the uncertainty surrounding their origin.

Foroutan noted that other studies have detected MNPs in atmospheric samples collected in urban, suburban, and even remote areas far from obvious sources. But how does it get there?

“Most existing research on MNPs has focused on marine environments, with oceans being considered the dead-end of plastic debris,” said Foroutan, an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center at Virginia Tech. “However, the source of airborne microplastics is not well understood, and there are critical knowledge gaps in this area. We know that MNPs have been found in marine atmospheric samples, but little is known about the processes and mechanisms that control the release and transfer of microplastics from oceans and seas into the atmosphere,” he added.  

Foroutan’s project will expand on existing research to determine if tiny MNP particles are, in fact, aerosolized by oceanic wave breaking and bubble bursting. His team will then investigate whether and how the size, shape, age, or material of the MNP particles affects the aerosolization. The experiment will not only allow for human risk assessment, Foroutan said, but it also may shed light on the “missing plastic paradox,” which states that 99 percent of plastic litter entering the open ocean is unaccounted for. 

To conduct its research, Foroutan’s team had to figure out how to reproduce realistic breaking waves and the ensuing bubble bursting in a small-scale laboratory setup. In response, team members designed and built an aerosol generation tank that consists of a closed-circuit, air-tight tank and two concentric tubes generating a uniform plunging sheet of water to simulate sea-spray aerosols. The resulting aerosolized particles can then be sampled in the headspace.

Foroutan's team will use the data to develop and parameterize a process model that could be used to estimate the surface flux of sea spray MNP aerosols. Finally, team members will integrate their MNP flux model into a large-scale atmospheric model to simulate and quantify the transport and deposition of sea spray MNP aerosols in relevant environmental compartments.   

The CAREER award is the National Science Foundation’s most prestigious award for early-career faculty, encouraging them to serve as academic role models in research and education and to lead advances in the mission of their organization. To satisfy the award’s requirements, CAREER recipients must find ways to integrate education and research into their projects, as well as conduct outreach.

“My long-term vision is to provide education and awareness to the public audience about modern air quality issues beyond traditional sources such as smokestacks or tailpipes,” Foroutan said.

To do this, his team will develop an educational exhibit at the Science Museum of Western Virginia in Roanoke. The exhibit will illustrate the physics of sea spray aerosols as well as marine and atmospheric microplastics, using a scaled-down version of the tank being used in the project.

Graduate students working on this project also will participate in summer camps at Virginia Tech that are aimed at pre-college students. Through a hands-on, problem-based experiment, campers will use microscope and image processing techniques to characterize airborne plastic particles.

From educating kids visiting the museum to helping environmental scientists who study airborne particles daily, this project has potential benefits for communities the world over.   

“Plastics are a significant environmental concern. They impact human, ecological, and environmental health,” said Foroutan. “This project could have a broad impact on human health, and our unique framework hopefully will provide a new way for environmental scientists and engineers to address this growing problem.”