Architects and building engineers aim to create safe, functional environments for people to live and work in. They follow detailed codes, regulations, and guidelines to ensure safety from structural and fire hazards, adequate ventilation, energy efficiency, and readiness for extreme events like 100-year floods. The current question is how the experience of a 100-year viral pandemic might influence building design and operations. How can societies protect buildings from a viral outbreak? Could public and institutional buildings be redesigned to help control outbreaks instead of just evacuating people? Is it possible for people to influence microbiomes inside buildings to reduce exposure to harmful pathogens?
At the University of Oregon’s Biology and the Built Environment (BioBE) Center, research focuses on the interactions among humans, buildings, and microorganisms, advocating for architecture to evolve to manage indoor microbiomes for health benefits. A recent paper combines research on indoor microbes with insights on the novel coronavirus to propose ways to reduce COVID-19 spread in buildings. Generally, people are concerned with eliminating microbes, especially during pandemics, but most microbes are beneficial to humans. This is part of the Old Friends Hypothesis or the Hygiene Hypothesis. Every individual has a unique microbiome composed of bacteria, fungi, viruses, and protozoa that inhabit the body. While some microbes support health, others can cause illness, affecting digestion, mood, and weight, and providing immune protection through skin microbes. Indoor spaces also have complex microbial ecosystems, and sterilizing these environments can lead to problems. Lower microbial exposure has been linked to conditions such as irritable bowel disease, asthma, and mood disorders.
Focusing solely on killing microbes can have undesirable effects, such as increased antibiotic-resistant bacteria indoors due to antimicrobial use. This has led researchers to examine indoor cleaning methods more thoroughly. Architectural design can impact indoor microbial communities through factors like layout, material choices, window positioning and attributes, lighting, and air movement strategies. Building managers can influence the amount of fresh air introduced and exchanged, as well as adjust humidity levels and cleaning practices. Recent studies suggest natural systems such as daylight and ventilation not only reduce energy use and enhance health but also promote diversified and less pathogenic indoor microbial ecosystems. Natural wood surfaces can decrease some viruses’ presence quicker than materials like stainless steel or plastic. Humidity is crucial; very dry indoor air, common during heating seasons, can dry out mucous membranes and skin, facilitating deeper respiratory particle penetration and increasing infection risks.
Maintaining indoor air with 40%-60% relative humidity can reduce these risks and lower viral infectivity by disrupting viruses’ outer layers. Drawing from past research, guidelines for improved building operations during COVID-19 aim to decrease indoor viral spread. They recommend introducing more fresh air, increasing air exchanges, maintaining air humidity at 40%-60%, utilizing natural ventilation by opening windows, enhancing access to daylight, and employing specific disinfection strategies like UV-C light in healthcare. Home strategies mirror these guidelines, such as isolating symptomatic residents next to a bathroom with a continuously running exhaust fan to control airflow. The research team aims to identify communities of beneficial microbes. They are collaborating with organizations to develop real-time indoor microbial monitoring to enhance operating practices and contact tracing. This will improve pathogen monitoring and data-driven understanding of healthy indoor microbiomes.
Manufacturers are exploring adding beneficial microbes to indoor environments to compete with or combat harmful ones, moving away from traditional harsh cleaning methods. Such ideas hold promise but require thorough research and regulation by bodies like the Environmental Protection Agency, which oversees antimicrobial cleaning products. The architecture and construction industry have focused on standards to promote building performance and human health for years. It is now time to emphasize cultivating healthy indoor microbiomes.