Coronavirus graphic with map

Up in the air

Modeling aerosol travel in the lungs could improve COVID-19 treatments

Before COVID-19, the term “aerosol” was hardly a household name. It called to mind cans of spray paint or sunscreen. However, these days, almost everyone knows it as the main culprit for spreading the novel coronavirus—and College of Science and Engineering professor Suo Yang says taking a closer at aerosols is key to mitigating the disease and helping Minnesota reopen.

Yang, a Richard and Barbara Nelson Assistant Professor in the Department of Mechanical Engineering, usually studies reacting flow in combustion engines. He works to simulate the process of combustion in engines of machines like jets and rockets, and models the output of soot and how it contributes to air pollution. One of the most popular aerosols is PM2.5, the fine particulate matter responsible for air pollution.

Yang is currently using his experience modeling aerosols to predict how the coronavirus travels inside the human respiratory system.

“I think the College of Science and Engineering is very suitable to do this work,” Yang said.

“[Medical professionals] focus on the clinical stuff. But when you talk about air transmission, or aerosols, or the mechanics of medical devices, those things are what College of Science and Engineering researchers know about,” he said.

Optimizing medical treatments

Aerosols are invisible to the naked eye and ejected from our mouths when we exhale or speak. When an infected person does this, the SARS CoV-2 virus hitches a ride on those aerosols, which then land on nearby surfaces or are inhaled by another person.

Funded by the University of Minnesota’s Collaborative Outcomes: Visionary Innovation and Discovery (CO:VID) grants program, Yang is studying the trajectory of the virus once it’s inhaled—particularly how it travels through the lungs.

“The key symptom of COVID-19 is the lung inflammation,” he explained. “So, we’re trying to understand how the virus aerosol is transported and deposited in the lung. Where is the high concentration zone? What’s the pattern? Does it depend on other conditions?”

By creating models of human lungs based on computed tomography (CT) scans from real COVID-19 patients, Yang hopes to inform the design of medical treatments, namely nasal sprays. His team has already begun running test simulations of aerosols in the back of the throat, nasal linings and trachea.

Deposition of virus aerosols in the front and back of the trachea
The researchers have begun preliminary simulations of the lung airways. The above images show virus aerosols deposited on the backside of the trachea (left) than on the front (right). Photo credit: Sai Ranjeet Narayanan

Then, Yang plans to map how medicine particles travel throughout those same systems in order to test the effectiveness of treatments.

“There are already many different medicines which theoretically can be very efficient, but if we cannot deliver them to the right location efficiently, it’s useless,” he said.

“Once we optimize these options, we can give that information to the medicine companies, and they can create their products accordingly to most efficiently target the system," he added.

Yang is also partnering with biomedical engineering professor David Odde, who earlier this year released a model of how the virus functions within human cells. The two researchers are planning on combining their results to give a comprehensive recommendation on treatment design. 

On a separate project, Yang is collaborating with fellow mechanical engineering associate professor Jiarong Hong to model how the coronavirus travels throughout open spaces like classrooms and elevators.

Story by Olivia Hultgren

If you'd like to support this work and other COVID-19-related activities, visit the CSE Response Fund.