According to the Centers for Disease Control and Prevention, an estimated 35-to-65 million people in the U.S. contracted influenza from Oct. 1, 2023 to June 15, 2024. Each annual influenza epidemic in the U.S. can infect 5%-20% of Americans, with between 3,000 and 49,000 deaths at an estimated $10 billion in medical costs and $16 billion in lost earnings.
The flu is often transmitted in the air by respiratory droplets and aerosol particles, but it can also be spread through contact with contaminated surfaces. While respiratory droplets remain in the air for about five minutes, the influenza virus can survive on hard surfaces for 24-to-48 hours.
Contaminated surfaces play a significant role in the spread of viruses like influenza in the built environment. To successfully clean the surface with available approaches and protocols, the question of how the virus reaches the surface and what happens next must be answered.
Civil and Environmental Engineering Associate Professor Shamia Hoque recently started a research project that aims to better understand the mechanisms driving the interaction of viruses within the built environment and surrounding surfaces. Hoque’s three-year, nearly $400,000 research is funded by the National Science Foundation. She is working with Carolina Distinguished Professor Qian Wang from the University of South Carolina Department of Chemistry and Biochemistry. They have previously collaborated on research analyzing viruses and how they move in the air and on surfaces.
“We’ve done research on areas such as the type of bacteria released, how people get exposed, and how we design and orientate our indoor spaces. It was a combination of fluid mechanics, aerosol physics and the indoor built environment,” Hoque says.
The COVID-19 pandemic highlighted the need for more insight on how air flow, viruses and surfaces interact.
“Instead of traditional methods, we may need to find a better way of how to clean because we're evidently not doing a good job,” Hoque says. “We have bacterial resistance coming from hospitals as well as infection transfer risks within buildings. With this research, we’re trying to understand the fundamental question of where the virus or bacteria goes if it attaches to a surface, and if so, why?”
Wang added that the research will allow for a better understanding of virus attachment, which will lead to improved strategies.
"The study of the correlation between virus attachment on indoor surfaces and airflow will help us better understand the mechanisms of viral transmission and optimize ventilation systems for reducing the spread of airborne pathogens in indoor environments," Wang says.
Hoque aims for her research to have variables on both ambient conditions and material types to give people an opportunity to determine the chances of bacteria or viruses attaching or detaching. This could be applied to cleaning, disinfecting and designing surfaces.
“We’ll study at least three types of viruses to see whether we can cover some ranges and give us an insight on how they work,” Hoque says. “We’ll also look at different building materials and explore how airflow conditions influence virus behavior with surfaces.”
Hoque and Wang’s research will be a combination of computational and laboratory work to connect the research between viruses and airflow. They plan to use particle image velocimetry, a non-intrusive optical flow measurement technique, to visualize airflow and particle movement. According to Hoque, few researchers have tried to connect the airflow in buildings and how it relates to viruses in the context of surfaces.
“There is ample knowledge, but we’re focusing on intersecting those fields to find answers on viruses, their movement in air and its connection to surfaces. That is the missing part,” Hoque says. “We also plan to look at movement of air and the boundary flow because both are connected to viruses. Having Dr. Wang is a good compliment because he understands viruses.”
Hoque’s expertise is in viral aerosols and inert particles in indoor environments. But with this project, she is looking at biological particles, which are viruses, and their connection with surfaces.
“We’ll look at the surface kinetics literature, which has information on adhesion and detachment, in terms of surface charges. But it's not necessarily connected to the built environment and all types of surfaces like walls or wood. We’ll see how that connects to viruses, which is the intersection of different fields,” Hoque says.
The research applies to all surfaces. Hoque plans to start by characterizing new surfaces before moving to used and aged ones. She says that the final vision of her research is to consider how viruses attach and detach to surfaces and incorporate it into architecture to reduce the risk of infection. This could apply to surfaces in all buildings like hospitals, schools and homes.
“It’s about taking into different possibilities,” Hoque says. “For example, if it’s a home and a child is allergic, how particles attach and detach might be something to consider when choosing surface type for building materials.”
Hoque also wants to consider her research in terms of personal hygiene and behavior. One example is when a child in school is asked to constantly use disinfectant on their hands. This is not ideal if they have eczema on their hands.
“Perhaps we can design the surfaces of the tables in a way that if one kid sneezes, it remains there, and you simply clean the surface. Or, figuring out a way of making sure that a location is cleaner, so a child who might be more sensitive can be in that part of the room,” Hoque says.
Hoque also hopes that there is a better understanding and application of the consideration of viruses when designing indoor spaces. “With any other machinery or equipment, no one says, ‘You're going to get sick or be in an accident, and it's fine.’ But with buildings, it’s okay to say something like, ‘There’s a little mold over there, so we'll just paint over it,'” Hoque says.
Hoque believes it is important to change the mindset of accepting that people will get sick inside a building and transform it so that buildings where people work or live should be safe zones that do not make them sick.
“We need to have a different mindset,” Hoque says. “Instead of taking for granted that people will get sick in a building, the goal of this project is how can we accept that while reducing a particular risk.”