UC Davis, as part of a multi-institutional team, is working to change how buildings operate with new biosensors and a risk model to maintain energy efficiency
By KATELYN BURNS — science@theaggie.org
A multi-institutional research team, which includes UC Davis, began work on a project to develop a system capable of reducing pathogens in indoor air. The Bioaerosol Risk Assessment interVention Engineering (BRAVE) project features four main areas:
- Developing new biosensors that allow for the detection of pathogens and other pollutants in real time.
- Developing a risk model that uses the data from the biosensors to determine the current risk the detected pathogens pose to occupants.
- Changing how buildings operate, using tools to filter or ventilate the air and making suggestions to occupants: ultimately decreasing pathogens in indoor air.
- Assessing the project’s outcomes using epidemiological tools, with the goal of determining whether these efforts lead to better outcomes — such as less sickness for occupants and their families.
Christopher Cappa, a professor in UC Davis’ Department of Civil and Environmental Engineering and UC Davis’ BRAVE project lead, commented on the project and the university’s role in improving building ventilation.
“I’m super excited to see all of this really come together,” Cappa said. “We’ve never had the ability to do this real-time pathogen monitoring in a way that is scalable.”
The COVID-19 pandemic sparked new research and increased interest in indoor air quality. The BRAVE team is leveraging these new developments in technology into an engineering strategy that can improve indoor air quality.
Christine Johnson, a professor of medicine and epidemiology at UC Davis School of Veterinary Medicine and the director of the National Science Foundation (NSF) Center for Pandemic Insights, explained what made the COVID-19 pandemic unique.
“COVID-19 was the first pandemic to emerge with massive, globalized travel and social media playing a big role in how we receive and share information,” Johnson said.
The epidemiological triad, made up of pathogen, host and environmental factors, explains the spread. The changing environment — now with massive, globalized travel and social media — wasn’t the only thing responsible for the pandemic’s spread. As hosts, individuals were immunologically naive to the novel COVID-19 virus. The virus itself contributed to the spread in several ways.
This virus had such a vast array of responses, from asymptomatic to severe pneumonia. The less sick, or asymptomatic, would continue to travel and spread the virus. Not only did tit result in such a wide array of responses; it mutated fast and was capable of airborne transmission.
Airborne transmission is not the same as droplet transmission. Droplet transmission involves larger particles, with coughs and sneezes spreading the virus through droplets of saliva and mucus. On the other hand, airborne transmission involves smaller particles travelling further and remaining in the air even after the host has left the area. While 6 feet of social distance may have been enough to prevent droplet transmission and slow the initial spread, once the virus was capable of airborne transmission, 6 feet was no longer enough.
“We’ve got programs for monitoring water and prevention of waterborne pathogens, and it’s about time we do the same to every extent feasible for pathogens that move around through airborne transmission and continue to place a significant burden on society,” Johnson said.
Linsey Marr, a professor of civil and environmental engineering at Virginia Tech and the BRAVE project lead, commented on the project’s goals.
“[Advanced Research Projects Agency for Health (ARPA-H), the government agency funding the project], wants us to be able to detect 25 different things in the air, which is a lot,” Marr said. “Ultimately, they want us to show at least proof of concept that we can detect 100 different things in the air.”
The BRAVE project is still in its early stages. While teams at other institutions are working to further develop the biosensors, UC Davis prepares to eventually demonstrate their biosensors by integrating them into buildings across the country.
Buildings are currently designed to balance thermal comfort and energy efficiency, according to Marr.
“In order to save energy, you want your building to be tight and you want your air that you’re heating or cooling to mostly stay there and recirculate,” Marr said. “That means that things in the air — viruses, bacteria, fungi — can build up in the air over time if you’re not exchanging it with outdoor air to dilute it.”
While recirculating air is more energy-efficient while maintaining a comfortable temperature, recirculating air will eventually need to be filtered or ventilated for health. The biosensor and risk assessment model would be able to determine when intervention becomes necessary, and, otherwise, allow the air to continue to be recirculated and maintain peak energy efficiency. This process involves determining when the health risks make it worth spending that extra energy.
Why demonstrate the systems in buildings across the country? The climate impacts how the building is going to operate, which means testing in different climates are important. In Davis, the hot, dry environment in the summer means buildings have larger heating, ventilation, and air conditioning (HVAC) systems. More moderate climates may have smaller systems, changing the amount of air that can be moved. Alternatively, more humid environments can restrict how often the windows are opened. While BRAVE’s goal is to have general strategies, the final results must be adaptable to specific environments; every building is unique.
“Although the ideas that we have here are very general to any kind of environment, we’re very focused on childcare centers,” Cappa said. “Kids get sick a lot. There can be a lot of transmission through those areas, and so this can be a way to keep those kids healthier, their parents healthier and their families healthier; we think it could have some big impact.”
Currently, the UC Davis team is in discussion with childcare center providers and building managers to find the locations that will eventually be used to demonstrate the project, according to Cappa. The eventual goal is to develop a product that building managers and owners can buy.
“[Having the product] is one thing, and the second thing is that the product works and makes the air healthier and cleaner for building occupants, having less illness as a result,” Marr said.
Individuals have come to expect clean and safe water. The same should be expected of our air, indoors and out. The BRAVE project aims to achieve this with their biosensor, risk assessment model and engineering interventions that ultimately aim to help keep our indoor air clean and decrease the spread of sickness.
Written by: Katelyn Burns — science@theaggie.org
