Design and environmental variables—including building typology, spatial configuration, ventilation type, and microclimatic conditions—play a pivotal role in shaping indoor microbial communities. Abdin and Mahmoud (2024) emphasize how environmental inputs like soil, vegetation, climate, and air velocity influence microbial influx and behaviour, while Li et al. (2021) underscore the absence of computational tools to model spatially distributed infection risks. Liu et al. (2024) and Leung et al. (2019) further demonstrate that spatial layout, occupancy patterns, room functionality, and ventilation systems significantly alter microbial diversity and abundance, with natural ventilation supporting more diverse communities compared to mechanical ventilation.

Although these studies confirm the spatial sensitivity of microbiome composition, a gap remains in integrating spatial analytics and predictive microbial modelling into mainstream building performance assessments. This limits architects and engineers from anticipating microbial dynamics in design decisions.

Humans are one of the most significant microbial sources indoors. Liu et al. (2024) and Li et al. (2021) show that occupancy patterns influence microbial loading, with high-density use and varying activity levels reshaping microbiota in different zones. These human-associated microbes originate from the skin, oral, and gut microbiomes, and are redistributed through contact, bioaerosols, or dust (Li et al., 2021). Over time, the microbial fingerprint of indoor spaces is shaped by room function and disinfection schedules.

Interestingly, microbial transmission risk is also temporally dynamic, influenced by occupant movement patterns throughout the day (Liu et al., 2024). This highlights the need for time-based risk assessments alongside spatial analysis.

Building materials function as reservoirs and vectors of microbial transmission. Pacheco-Torgal et al. (2021) point to porous materials, like drywall, insulation, and untreated wood, as conducive to microbial retention and biofilm formation, especially in humid environments. These materials sustain long-term microbial viability, persistence, and indirect transmission. Improper material maintenance exacerbates this risk.

Challenges lie in how common construction materials are rarely evaluated for microbial compatibility. While moisture-resistant materials offer better control, their use remains limited to specialized buildings.

Together, these findings establish buildings as more than passive environments—they are active agents in microbial ecology. Despite extensive documentation of microbial influences by spatial design, human presence, and material choice, policies continue to overlook microbial factors in architectural planning and performance metrics.

Environmental and structural influences play a pivotal role in pathogen transmission within the BE. Argyropoulos et al. (2023) emphasize the significance of airborne transmission in microbiome dispersal, shaped by ventilation systems, airflow dynamics, temperature, and humidity. Inadequate or poorly maintained ventilation can unintentionally promote pathogen spread. Pacheco-Torgal et al. (2021) affirm that high humidity stabilizes droplet-based pathogens, while low humidity enhances aerosol persistence. Leung et al. (2019) highlight outdoor air and dust as key sources of indoor microbes, with geography and environmental factors shaping microbial profiles. The study also identifies that mechanical ventilation can reduce microbial loads, while moisture-rich spaces foster fungal growth. Similarly, Martinez and Morrow (2020), Morrow et al. (2021), and Skanata et al. (2022) highlight the role of aerosols in transmitting respiratory viruses, with particles that remain airborne, dispersing beyond 1–2 m (Wang, C. C. et al., 2021; Xie, X. et al., 2007; Dabisch et al., 2021). Abdin and Mahmoud (2024) stress the importance of grasping post-COVID-19 indoor infection dynamics, noting air stagnation, population density, and recirculation as key contributors, with pathogen buoyancy further influenced by particle mass, temperature, humidity, and human activity.

Consequently, it is imperative to examine the spatial and temporal pathogen dispersal patterns, alongside the development of science-based guidelines for safe indoor space utilization to mitigate future outbreaks.

Human activities such as coughing, sneezing, speaking, or even moving through a space contribute to bioaerosol generation and resuspension. Notably, Dietz et al. (2020) stress that SARS-CoV-2 is primarily transmitted through droplets and aerosolized particles released from the mouth. Pacheco-Torgal et al. (2021) highlights airborne microbial dissemination as a critical concern in enclosed environments, where pathogenic aerosols persist depending on airflow and ventilation.

Löhner et al. (2021) found that sneezing expels particles at speeds up to 14 m/s, enabling widespread dispersion. Argyropoulos et al. (2023) and Leung et al. (2019) noted that even minor physical movement can resuspend settled particles, increasing exposure risk. Prussin et al. (2020) highlighted actions like flushing toilets or vomiting, which aerosolize gastrointestinal viruses like norovirus. Zhang et al. (2023) estimated an 18.7-fold increase in infection risk indoors due to suboptimal air movement. Meanwhile, Susswein et al. (2023) introduced GPS-derived mobility data, showing increased indoor occupancy during winter months, correlating with heightened transmission risk.

High-occupancy enclosed environments such as healthcare facilities and transit systems exhibit high aerosol transmission risk. Dietz et al. (2020) showed how confined, poorly ventilated public settings facilitate persistent aerosols. Gohli et al. (2019) found seasonal variation in airborne microbiota in subway systems, while Hopman et al. (2019) used genomic analysis to trace hospital infections to aerosolized particles from plumbing infrastructure.

In brief, the literature makes it clear that airborne transmission in BEs is a function of spatial design, environmental controls, and human behaviour. Despite these insights, policy translation remains weak, especially outside healthcare settings.

Zhang et al. (2023) describe fomite transmission as a two-step process: the contamination of environmental surfaces and the subsequent acquisition of viral particles through physical contact. Surface contamination is attributable to the deposition of viral droplets originating from speech or coughing by infected individuals near surfaces, and the direct transfer of the virus via contact. However, quantifying transferred viral loads presents challenges due to the limited and heterogeneous quantities of viruses present in the hands of the infector.

Likewise, Stephens et al. (2019) reviews three primary methodologies employed to assess fomite-mediated microbial transmission and its ramifications for human health: (i) experimental quantification of microbial transfer (ii) mathematical modeling of microbial exchange in conjunction with other exposure pathways (e.g., direct contact and aerosol transmission), and (iii) epidemiological investigations on transmission dynamics. These approaches collectively contribute to a nuanced understanding of the mechanisms underlying microbial dissemination via fomites and other vectors.

Numerous studies indicate that pathogens, including SARS-CoV-2, can persist for hours to days on materials such as plastic, metal, glass, cloth, and skin (Dietz et al., 2020; Chin et al., 2020; Hirose et al., 2021; Doremalen et al., 2020). In this regard, Dietz et al. (2020) assert that fomites function as viral reservoirs, enabling indirect transmission when individuals interact with contaminated surfaces, with the persistence of the virus on plastic, cardboard, and stainless-steel lasting several hours to days. Further, Ghasemi et al. (2021) used molecular simulations to show that viral adhesion varies by material (e.g., aluminum, copper, copper oxide, polyethylene, and silicon dioxide), with the strongest binding on silicon dioxide and weakest on polyethylene. Polyethylene surfaces also facilitate viral transfer through water, whereas silicon dioxide surfaces cause viral damage through water.

Pacheco-Torgal et al. (2021) emphasize that high-touch surfaces, including doorknobs, elevator buttons, desks, and countertops, are contact points for microbial transfer between individuals and the environment. Further, within hospital environments, the contamination of high-touch surfaces, including medical devices and hospital furnishings, is a pivotal factor in the dissemination of several pathogens, as elucidated by Dalton et al. (2020).

In the same way, Sah et al. (2023) investigated the profound health implications of microbial exchange between humans and the BE, within a laboratory handling SARS-CoV-2 samples during the COVID-19 pandemic. The researchers sampled a range of surfaces, including floors, benches, and sinks, across the laboratory over 3 months, revealing elevated bacterial diversity on the floors. The floors were primarily colonized by environmental bacteria, while benchtops exhibited a greater prevalence of human-associated microbial taxa.

Fomite transmission is a critical vector for pathogens, heightening the risk of cross-infections across healthcare environments, public spaces, and the food industry (Abraham et al., 2021). Liu et al. (2024) detected SARS-CoV-2 RNA on surfaces across restaurants, grocery stores, and healthcare facilities, underscoring its significance in indoor settings.

In this context, Abraham et al. (2021) elucidates that hospital-acquired infections (HAIs) remain a global health concern, with fomite transmission playing a significant role in community settings like healthcare settings, transportation hubs, and public gatherings. This underscores the necessity for enhanced infection control strategies during epidemic and pandemic situations. Similarly, a review by Dalton et al. (2020) highlights the critical role of the BE in pathogen transmission within healthcare settings, where the environment acts as a reservoir for multidrug-resistant organisms. Research finds that hospital design elements influence microbial transmission, with private room configurations and certain surface types associated with a reduced risk of HAIs, highlighting the importance of environmental factors in infection control.

Notably, fomite transmission extends beyond healthcare and public spaces to food-handling environments, where contaminated surfaces serve as vectors for pathogenic microorganisms and antibiotic-resistant bacteria. Accordingly, Valentino et al. (2022) highlight that microbial communities adapt to specific microclimatic conditions within these environments, often forming biofilms allowing them to persist on surfaces despite routine cleaning and disinfection, supporting the hypothesis that these environments may select for resistant and pathogenic microorganisms.

In addition, Wang et al. (2022) investigated fomite transmission, within an office setting, proposing that microbial invaders could be identified through microbial interaction networks, with contamination levels highest on hands and decreasing with geodesic distance from touchpoints, highlighting the critical role of human behavior in microbial dispersal and contamination dynamics. These findings support public health interventions addressing microbial interactions and anthropogenic factors alongside pathogen-specific disinfection measures.

Furthermore, several respiratory viruses, including the coronavirus, and coxsackie virus can survive on surfaces for several days, potentially facilitating infection if proper disinfection protocols are not followed (Kutter et al., 2018). Vassallo et al. (2022) highlight that densely populated urban environments are reservoirs for antibiotic-resistant bacteria (ARB) and genes (ARGs), its spread influenced by surface proximity, hygiene practices, and urban infrastructure. Airports, airplane cabins, shared facilities, and public transportation surfaces are key vectors for dissemination because of high-contact surfaces and inadequate sanitation. Similarly, urban green spaces, while beneficial, can host antimicrobial-resistant microorganisms (ARMs) due to atmospheric deposition and surface contamination from human-animal interactions.

Additionally, Leung et al. (2021) examined microbiomes and resistomes of public transit systems in six cities across three continents. Results indicate city-specific factors as primary determinants of microbiome diversity, revealing significant geographic variation in species, strain-level growth profiles, and resistance genes. The analysis suggests human skin, soil, and public transit surfaces are key sources of resistance genes, highlighting the need for further investigations to understand the factors shaping public transit systems microbiomes. Likewise, Gohli et al. (2019) confirm that subway surfaces are key vehicles for microbial transmission, due to constant interaction between people and the BE.

The COVID-19 pandemic reinforced the critical link between public health and the BE, revealing significant correlations between morbidity and mortality rates and factors such as housing quality, socioeconomic status, and urban infrastructure (Ghasemi et al., 2021). To foster resilient, sustainable urban development, there is a call for structural modifications to public spaces, transportation networks, and hygiene practices in cities, benefiting marginalized populations disproportionately affected by the pandemic. Despite advancements in understanding the virus’s transmission via surfaces, there remains a substantial gap in empirical data on nanoscale interactions between SARS-CoV-2 and various materials, highlighting the need for further research to clarify mechanisms of viral adhesion and its potential for surface transmission.

The interaction between human-associated microbiomes and indoor surfaces contributes to the dynamic exchange of microbial communities, potentially altering pathogen survival and transmission dynamics, as elucidated by Pacheco-Torgal et al. (2021). Liu et al. (2024) asserts that respiratory pathogens may be transmitted through direct contact, dust, or fomites when an individual contacts a contaminated surface and subsequently touches their facial, oral, or nasal regions. Likewise, Prussin et al. (2020) emphasize that gastrointestinal viruses are commonly transmitted via fomites like food, doorknobs, and electronic devices when individuals touch contaminated surfaces and transfer the virus to their mucosal membranes through hand-to-mouth contact.

The home BE predominantly harbors human-associated bacteria (human microbiomes) serving as microbial reservoirs (Xie et al., 2023). High-contact (e.g., sponges, toothbrushes, faucets, fridges, keyboards, pens, credit cards, cellphones, and keys) and low-contact surfaces (e.g., shower drains, countertops, sinks, walls, ceilings, floors, cutting boards, and stove knobs) demonstrate enhanced bacterial viability due to frequent microbial transfer from humans. However, Xie et al. (2023) suggest that most bacteria associated with human skin microbiomes are non-viable, indicating that transfers may result in diminished bacterial viability within the BE, with bacterial cultures in sterile settings displaying significantly higher average viability than those in non-sterile environments, weakening by 45% on sterile and 90% on non-sterile surfaces, over a week. These findings suggest that environmental exposure may reduce bacterial viability, contrasting initial expectations regarding high-contact surfaces.

Similarly, Richardson et al. (2019) explored the microbiota of a college dormitory, focusing on cohabitation’s impact on microbial communities. Their analysis identified distinct microbial interaction networks, with hands as the primary vector for transmission, while shoe-associated samples demonstrated more autonomous interaction patterns, highlighting the complexity of microbial dynamics in communal environments.

Humans are also identified by Leung et al. (2019), as key contributors to indoor microbiomes through skin-emitted microorganisms that form a “personalized microbial cloud” unique to individual occupants. However, well-ventilated or sparsely occupied spaces dilute this effect, resembling outdoor microbial communities. Factors including occupancy density, frequency, and ventilation strategies further influence human impact on surface transmission of microbiomes.

Moreover, Mhuireach et al. (2022) investigated bacterial transfer dynamics between indoor plants and human skin in a controlled climate chamber, revealing that soil-derived microbial taxa increased skin microbial diversity for at least 24 h post-contact, significantly influencing skin microbiome dynamics. This research highlights the health implications of interactions between indoor plant-associated and human-associated microbiomes, emphasizing the need for further investigation in urban living environments.

Therefore, fomite transmission is a recognized but often overlooked infection pathway in multiple BEs, including healthcare facilities, public spaces, food processing environments, and residential settings. While many studies have examined persistence and cleaning efficacy, few insights have influenced spatial or infrastructure-level policy. Further, as seen, viral fomite transmission gained attention during the COVID-19 pandemic. However, there remains comparatively limited empirical research focused on bacterial and other microbial communities deposited on surfaces in everyday BEs, showcasing a gap in the current literature.

Pacheco-Torgal et al. (2021) sheds light on plumbing systems as reservoirs for microbial colonization, with biofilm formation on pipe surfaces facilitating pathogen persistence, which later become aerosolized through water distribution points, including taps, and cooling towers, leading to inhalation-based transmission. Stagnant water within piping networks exacerbates microbial proliferation, particularly in sections of plumbing infrastructure where disinfectant residuals dissipate over time.

On a similar note, Donohue and Mistry (2024) emphasize that hot water systems within the BE, are optimal for the proliferation of pathogens, including nontuberculous mycobacteria (NTM). The investigation concluded that heating water diminishes the efficacy of chemical disinfectants, like chlorine or chloramine, thereby raising the rate of microbial proliferation. The findings also revealed varying detection frequencies based on structural attributes, like age and size. Hence, it stresses the importance of rigorous disinfection protocols and targeted infrastructural adaptations within water systems.

To add, Kearney et al. (2024) highlight that the plumbing systems in healthcare infrastructures, including the u-bend or p-trap components in sinks, serve as reservoirs for carbapenemase-producing Enterobacterales (CPE) due to biofilm formation in areas that are challenging to decontaminate, exacerbating cross-contamination risks. Their empirical assessment of healthcare personnel highlighted the necessity for targeted interventions to fortify protocols for healthcare-associated infection (HCAI) transmission.

Waterborne transmission is further complicated by antibiotic-resistant bacteria (ARB) and genes (ARGs) in urban water systems. Vassallo et al. (2022) highlight that airport wastewater treatment facilities and airplane sewage contain higher concentrations of ARGs than other urban wastewater sources. Sewer leaks, overflows, and using wastewater for irrigation in urban green spaces also aid the spread and persistence of ARMs (antibiotic-resistant microorganisms), emphasizing the need for improved water monitoring and management. Additionally, Leung et al. (2021) identifies wastewater as a key source of resistance genes that lead to transmission, especially in public transit systems.

In summary, waterborne transmission is an overlooked transmission pathway in BEs, influenced by plumbing systems, disinfectant efficacy, and biofilm formation. A review of studies from 2019 to 2024 reveals a limited number on waterborne transmission related to the selected keywords. This highlights the necessity for additional research to better understand and develop effective strategies that enhance public health resilience.

Zoonotic viruses, transmitted from wildlife to humans, have increasingly contributed to outbreaks, with interspecific transmission occurring through both direct contact and domesticated animals (Syal, 2021), as evidenced by the COVID-19 pandemic.

Habitat encroachment, fragmentation, and biodiversity loss from human activities contribute significantly to disease emergence, stressing wildlife hosts and enabling viral shedding and mutation. Rodents, key reservoirs for zoonotic pathogens, frequent human-modified environments due to land use changes, especially from agricultural development, which introduce novel pathogens. Thus, an investigation by Mistrick et al. (2024) elucidates that agricultural and synanthropic habitats exhibited heightened microbiome richness, diversity, and evenness in wild Peromyscus mice, relative to undeveloped forest habitats. Despite a low overall abundance of putative pathogenic bacteria, these pathogens were more common in agricultural settings.

Furthermore, Dalton et al. (2020) indicates that animals, including therapy and service animals in hospitals, are reservoirs and vectors for pathogens, facilitating the transmission of hospital-associated microorganisms, and the intersection between hospital and community microbial ecosystems.

The interplay between climate change and accelerated population growth has created significant environmental challenges, including resource depletion, ecological degradation, and shifts in socio-ecological interactions, as highlighted by Nhamo et al. (2022). These have facilitated the emergence and transmission of microbiomes with pathogenic potential. Modifications to the BE and ecological infrastructure established new pathways for pathogen transmission, leaving hosts more vulnerable. The COVID-19 pandemic illustrated how altered human-nature interactions exacerbate the transmission of infectious agents, threatening public health.

Similarly, predicting pathogen transmission due to increasing human-environment interactions helps anticipate risks and develop mitigation strategies. Vector-borne diseases (VBDs) exhibit varying ecological responses to environmental changes, influenced by interactions between vectors, hosts, and socio-ecological factors. Utilizing methodologies like cumulative pressure mapping and machine learning, Skinner et al. (2023) demonstrate that the human footprint—encompassing BEs, infrastructure, agricultural land, and population density—predicts VBD occurrence, with thresholds defining the transition from diseases associated with lower human pressures to higher human pressures. These responses underscore land-use transitions for shifting infectious disease burdens and public health interventions.

Earthquake-induced tsunamis cause widespread destruction of both nature and BEs, exacerbating the risk of respiratory infections (RIs) through air, water, and surface transmissions. Mavrouli et al. (2021) reviewed 47 studies on post-tsunami disease emergence, revealing outbreaks of polymicrobial RIs, influenza, measles, and tuberculosis among survivors. Contributing factors to the persistence of these infections include overcrowded evacuation shelters, destroyed healthcare infrastructure, heightened pathogen exposure in flooded areas, regional endemic disease patterns, and insufficient vaccination coverage.

Consequently, understanding the complex interplay of ecological, environmental, and societal factors in pathogen transmission is essential for mitigating disease risks. Evidence emphasizes how habitat changes, human-wildlife interactions, land-use transitions, and catastrophic events influence the emergence and spread of infectious diseases. As global challenges accelerate, interdisciplinary research and public health strategies are crucial to minimizing threats to human health.

Bliss and Kopec (2022) explore historical and modern urban design strategies for infection control, from lazarettos and leprosy centers to contemporary pedestrian flow and open space design. Their book highlights lessons from COVID-19 for healthier environments post-pandemic, making it a valuable resource for advancements in architecture and urban planning.

To mitigate microbial proliferation and transmission through building materials, Pacheco-Torgal et al. (2021) asserts that selecting antimicrobial, moisture-resistant, or non-porous surfaces significantly reduces microbial adhesion and colonization, prevents water retention, and inhibits microbial growth. Maintaining optimal humidity levels, adequate ventilation, routine disinfection, and assessing microbial contamination on these materials contribute to effective management of biofilm formation and microbial persistence in the BE.

Li et al. (2021) underscore the critical public health challenge of microbial pathogen transmission in high-occupancy BEs, intensified by the COVID-19 pandemic. They propose a computational framework integrating Building Information Modeling (BIM), occupancy data, and pathogen transmission models to assess room-level outbreak risks using building characteristics, occupant interactions, and hygiene practices. Furthermore, their web-based system facilitates real-time communication of outbreak risks, providing insights to improve infectious disease management in BEs, like limiting occupancy levels and adjusting facility usage schedules based on risk distribution across rooms.

Gottel et al. (2024) examine the MoBE, encompassing diverse bacterial, archaeal, fungal, and viral communities linked to the BE, highlighting the significant risk of colonization by antibiotic-resistant pathogens via surface transmission or inhalation. The authors cite studies cataloguing microbial composition across BEs to guide in-vitro investigations focused on replicating conditions conducive to pathogen persistence.

Furthermore (Gottel et al., 2024), paves the way for developing and validating biocontrol strategies, like Bacillus-based cleaning products and printable materials to mitigate multidrug-resistant infections. The review proposes strategies to combat antibiotic-resistant pathogens and positions biocontrol as a viable alternative to traditional antimicrobial approaches, highlighting the efficacy of resilient Bacillus spores for sustainable pathogen control in BEs.

In summary, effectively mitigating microbial transmission in BEs requires a comprehensive approach combining architectural design, spatial planning, and technology. Historical and contemporary strategies highlight structural interventions, while data-driven solutions provide valuable insights for mitigating outbreak risks. Together, they highlight interdisciplinary research and innovation for creating resilient indoor environments post-COVID-19.

Mitigating airborne and dust-borne transmission requires optimized ventilation systems. Mechanical ventilation with advanced filtration effectively reduces microbial loads, while natural ventilation promotes microbial exchange with outdoor air, lacking control over specific microbial components, as studied by Leung et al. (2019).

On a similar note, Argyropoulos et al. (2023) emphasize that natural ventilation is cost-effective but variable in airflow and may bring in contaminants, while mechanical ventilation provides better control and filtration, albeit at a higher financial cost. In both systems, the efficacy of pathogen removal is primarily determined by airflow rates and movement patterns; downward displacement (DV) with 4 ACH (Air Changes per Hour) is indicated as most effective, while upward DV may heighten infection risk. Furthermore, personalized ventilation (PV) enhances air quality and mitigates transmission risk but loses efficiency in multi-story buildings due to natural ventilation. Notably, increasing ventilation rates above five ACH has lowered pathogen concentrations, but presents challenges for sustained implementation.

Likewise, Dietz et al. (2020), Pacheco-Torgal et al. (2021), Löhner et al. (2021) and Prussin et al. (2020) says mitigating airborne diseases like COVID-19 requires optimizing ventilation to increase air exchange rates and dilute microbial concentrations. Implementing fresh air ventilation, portable air purifiers, high-MERV (Minimum Efficiency Reporting Values)-rated filters and High-Efficiency Particulate Air (HEPA) filtration in HVAC systems effectively remove airborne pathogens, while UV-C (ultraviolet light with wavelengths between 100 and 280 nm) lighting in high-risk areas and Ultraviolet germicidal irradiation (UVGI) provides extra protection against microbes but needs precise placement to prevent harm to occupants. Contrastingly, Zhang et al. (2023) found enhancing filter efficiency to be the most consequential intervention, effectively reducing transmission risk in a supermarket to 0.33% when at maximum efficiency.

Additionally, the CLEAN 2020 summit emphasizes the necessity for a multifaceted approach to reduce viral transmission in indoor environments, as highlighted by Martinez and Morrow (2020) and Morrow et al. (2021). The summit advocates that eliminating the infectious agent is most effective, with building design and engineering measures like enhanced ventilation, filtration, transmission barriers, UVGI, and increased outdoor air dilution reducing viral exposure. The Summit also underscored the importance of developing long-term cleaning strategies that balance decontamination with human health, material integrity, and environmental impact.

Architectural design plays a critical role in pathogen dissemination, as highlighted by Zhang et al. (2023), who used agent-based modelling to simulate respiratory pathogen transmission in a supermarket. Interventions like multiple exits (lowered infection risk to 0.31%) and shelf layouts with multiple checkout lanes (risk reduced to 0.26%) decreased airborne transmission. Integrating strategies—structural, environmental, and human behavioural controls—resulted in 8 h without infections, signifying the importance of spatial planning and airflow optimization in controlling airborne pathogens.

Again, Abdin and Mahmoud (2024) illustrate how architectural design directly influences public health outcomes through curbing the spread of infection, by considering key factors such as airflow, recirculated air, and occupant proximity. Additionally, Pacheco-Torgal et al. (2021) also asserts that increasing natural ventilation through architectural design modifications, such as operable windows and ventilation shafts, further enhances indoor air quality and minimizes the risk of aerosol-based transmission.

Furthermore, environmental factors such as air temperature, relative humidity, and airflow patterns significantly influence pathogen viability, as elucidated by Dietz et al. (2020). The authors assert that maintaining optimal indoor lighting and temperature conditions is pivotal to controlling viral transmission. Research suggests that daylight exposure can reduce bacterial viability and influence the survival of viruses such as SARS-CoV-2. Moreover, Pacheco-Torgal et al. (2021) and Dietz et al. (2020) emphasized that modulating air temperature and maintaining indoor humidity levels between 40% and 60% can help reduce pathogen viability and transmission.

Moreover, Leung et al. (2019) recommend strategies such as maintaining robust ventilation, and addressing fungal and mold growth using environmentally sustainable mold removal products, coupled with strategies to control indoor humidity.

Additionally, Hopman et al. (2019) underscore the risk of airborne transmission of Carbapenemase-producing Pseudomonas aeruginosa in hospital environments, advocating for enhanced disinfection protocols for hospital drains, redesigning plumbing systems to minimize microbial reservoirs, and reconsidering the placement of sinks and showers in high-risk areas to limit infection spread.

The SARS-CoV-2 pandemic has underscored the importance of face masks in mitigating the transmission of respiratory droplets. Argyropoulos et al. (2023) indicates that masks, particularly N95 respirators, reduce droplet dispersion, although factors such as leakage and mask type influence their efficacy. This is confirmed by computational fluid dynamics (CFD) and large eddy simulation (LES) studies, though smaller droplets can persist in the air for prolonged durations. Prussin et al. (2020) also report interventions, like enforcing face masks and spatial distancing measures, as pivotal in minimizing the dissemination of aerosolized viral particles within BEs. Zhang et al. (2023) further concluded that implementing universal mask-wearing was the most efficacious intervention, reducing the infection risk to 0.08%.

Additionally, Dietz et al. (2020) highlight that protective environment (PE) rooms, which are positively pressurized to protect immunocompromised patients, can facilitate the migration of aerosols into high-traffic corridor spaces when doors are opened. In contrast, airborne infection isolation (AII) rooms using negative pressurization may expose occupants to adjacent airborne pathogens. Thus, hospital designs should decouple thermal conditioning from ventilation systems to increase operational resilience and flexibility during routine care and disease outbreaks.

Computational modelling is instrumental in optimizing infection control strategies. Aganovic et al. (2024) introduced a novel quanta-independent approach to address the limitations of the Wells-Riley model, which, despite its extensive use for modelling airborne transmission risk and assessing indoor infection control efficacy, is highly sensitive to variations in viral load, potentially leading to inaccurate risk predictions. The new approach concentrates on removal rates, room volume, and occupancy duration, thus providing a more robust assessment under steady-state and non-steady-state conditions.

Likewise, Löhner et al. (2021) reviews advancements in high-fidelity modelling for pathogen propagation, transmission, and mitigation within BEs, using differential equations to simulate airflow, particle dynamics, and UV radiation in indoor spaces and HVAC systems. Coupled with computational methods for crowd and fluid dynamics, these provide improvements in simulating aerosol transmission among moving pedestrians, contributing to the design of safer indoor environments, optimization of HVAC systems, and enhancement of protective measures, thereby strengthening resilience against future infectious disease outbreaks.

Moreover, Voss (2022) explores the integration of AI-powered surveillance systems, real-time diagnostics, and automation, as transformative tools in infection prevention and control (IPC). The research underscores the necessity for enhanced collaboration between acute and long-term care settings, advocating for a unified regional network in IPC. It emphasizes the role of engineering solutions in mitigating transmission risks, particularly of airborne and waterborne pathogens.

Additionally, a novel methodological framework, employing an aerosolized bacteriophage and its host, was developed by Skanata et al. (2022), to detect viable viral particles. This approach found viable particles to traverse distances up to 18 feet within 15 min in a classroom equipped with advanced HVAC systems, with dispersal notably attenuated when relative humidity exceeded 40%. The method is adaptable for diverse virus-host systems, providing a quantifiable measure of airborne transmission in BEs.

Further, Makris et al. (2024) presented the ICEE (Infection Control’s Energy Efficiency) index, a novel metric developed to evaluate the effectiveness of ventilation strategies in mitigating airborne pathogen transmission while accounting for energy demands, using a coherent analytical framework. Thus, the study provides essential insights for designing ventilation systems.

Recent research during COVID-19 highlights that reducing indoor occupancy, rather than mobility, is crucial in lowering airborne disease transmission (Susswein et al., 2023). Behavioural interventions promoting outdoor activity, especially in urban areas, have effectively reduced case rates, with regional variations influencing seasonal transmission patterns. Thus, Susswein et al. (2023) offers critical empirical insights into the relationship between human behaviour, the BE, and infection risk, thereby informing more effective public health strategies for managing seasonal and pandemic respiratory pathogens.

Similarly, Löhner et al. (2021) suggest behavioural interventions like avoiding exhalation wake paths, wearing N95 masks, regulating pedestrian traffic, and utilizing plexiglass barriers or face shields to reduce transmission risks, though their efficacy depends on proper design. In addition, Zhang et al. (2023) assert that customer control measures—such as tripling entry intervals at supermarkets—demonstrated notable efficacy, reducing the infection risk to 0.10%. In their study, customer control was the most effective out of other strategies, lowering the infection risk to a mere 0.04% by minimizing interactions between susceptible and infected individuals, surpassing sanitary measures in efficacy. Leung et al. (2019) also suggested regulation of occupant density and frequency as instrumental in minimizing microbial proliferation and improving overall indoor air quality.

In short, the effectiveness of biocidal treatments must be rigorously assessed to ensure both efficacy and safety. Moving forward, continued research and innovation in air quality management, coupled with evidence-based design improvements, will be essential in enhancing indoor environments.

Mitigating fomite-mediated transmission necessitates rigorous sanitation measures. While Zhang et al. (2023) primarily focus on airborne transmission and its related interventions, the acknowledgment of surface-based transmission routes as a critical pathway for SARS-CoV-2 spread in indoor environments implies the importance of comprehensive fomite-based mitigation strategies, including regular disinfection of high-touch surfaces and promoting hand hygiene.

Additionally, cleaning practices are effective in significantly reducing microbial loads and their transmission, with a single wipe of a wet cloth eliminating most bacteria and viruses, while disinfectants decrease pathogen levels, as emphasized by Leung et al. (2019). However, microbial recolonization can occur swiftly, as evidenced by their studies, highlighting the necessity of more frequent cleaning protocols in high-occupancy environments, to mitigate the risk of microbial transmission and to maintain hygiene standards.

Likewise, Dietz et al. (2020) emphasize that to mitigate fomite transmission, building operators must implement rigorous surface sanitation protocols, employing alcohol-based sanitizers and bleach solutions in high-contact areas like sinks, toilets, and communal workspaces. Research shows that hand sanitizers with 62%–71% ethanol effectively deactivate SARS-CoV-2. Continuous surface disinfection in shared spaces, strategic placement of hand hygiene stations, and clear signage promoting handwashing reduce the risk of fomite-mediated transmission.

Similarly, Prussin et al. (2020) advocate for frequent and systematic disinfection of high-contact surfaces using virucidal agents with proven efficacy against enveloped viruses, and for the promotion of stringent hand hygiene practices, including routine handwashing with antimicrobial soap and the use of alcohol-based hand sanitizers. Moreover, the integration of real-time environmental monitoring systems assesses contamination dynamics and informs adaptive cleaning regimens, particularly in high-occupancy and healthcare settings.

Additionally, Valentino et al. (2022) underscore the ineffectiveness of sanitation protocols in vegetable processing facilities at eradicating hazardous and antibiotic-resistant microorganisms from food contact surfaces. The authors suggest that widespread biocide use may increase selection pressure for resistant strains. These findings underscore the importance of incorporating microbiome mapping into routine monitoring frameworks within food production environments, alongside strict hygienic practices during vegetable harvesting and processing, to enhance food operators’ capacity and ensure microbiological safety and overall food quality.

To add, Sah et al. (2023) examine clinical laboratory microbiota, mapping microbial communities within these contexts, hence, enriching the understanding of potential sources of laboratory-acquired infections and supporting the refinement of safety protocols aimed at safeguarding healthcare workers.

Similarly, Dalton et al. (2020) emphasize that effective strategies for controlling microbial transmission in hospital settings require a comprehensive, integrative approach that targets the hospital environment, including manual cleaning protocols, no-touch disinfection technologies (e.g., UV irradiation), and architectural modifications. However, human error and microbial resistance often limit their success, reinforcing the need for multifaceted approaches, such as human-centered interventions, particularly hygiene practices like patient decolonization and healthcare worker hand hygiene.

Furthermore, Pacheco-Torgal et al. (2021) stress the importance of utilizing EPA-registered biocidal agents for surface disinfection, supplemented by behavioural interventions such as hand hygiene promotion and minimizing unnecessary contact with shared surfaces, to ensure the effective inactivation of microbial contaminants on frequently touched surfaces.

Advancements in antimicrobial surface materials provide promising solutions for infection control. On this note, Abraham et al. (2021) highlights copper and its alloys as effective antimicrobial agents, rendering pathogens like E. coli O157, nosocomial pathogens, and SARS-CoV-2 inactive on contact. Using copper-based surfaces in healthcare facilities, food industries, and public spaces may significantly reduce pathogen transmission, emphasizing the importance of further investigation into copper materials as an infection control strategy, especially during the COVID-19 pandemic. Pacheco-Torgal et al. (2021) further underscores the adoption of surface materials with antimicrobial properties or self-disinfecting capabilities, such as copper alloys or nanostructured coatings.

BEs are critical in transmitting infectious diseases, with ventilation rates, humidity, and surface characteristics significantly influencing pathogen viability and spread. Lam et al. (2022) found that electrochromic (EC) windows, which adjust daylight intensity, significantly reduced bacterial growth by up to 100% and fungal growth by up to 42% on surfaces like PVC, polystyrene, and glass. These findings highlight the importance of integrating EC windows in healthier indoor environments like offices, homes, aviation, and healthcare settings while suggesting that indoor daylight exposure can potentially serve as an effective surface disinfection alternative.

In addition, Pacheco-Torgal et al. (2021) emphasize integrating biophilic design principles, such as the introduction of beneficial microbial communities through indoor plants or microbiome-friendly materials, to further contribute to a healthier indoor microbiome and enhanced resilience against pathogenic colonization.

Considering the pandemic, there is a pressing need for automated, intelligent, and precise disinfection solutions, including autonomous disinfection robots utilizing ultraviolet (UV) technology (Yang, G. et al., 2020), to mitigate pathogen transmission and prevent infectious disease outbreaks. In this regard, Liu et al. (2024) proposed a novel enhanced fomite-based pathogen transmission model to evaluate infection risks from disinfection robots’ schedules and human interactions. A mixed-integer programming model optimized disinfection schedules and routes, showing significant efficacy in reducing infection risk in buildings with fewer than 50 rooms. This research highlights the potential for reducing exposure to infectious diseases and addressing community transmission hotspots while offering scalability and adaptability across diverse facility types, configurations, and sizes.

Similarly, Hu et al. (2020) address the risk of pathogen transmission in mass gatherings like hospitals, schools, and airports by introducing a robotic disinfection framework that utilizes simultaneous localization and mapping for autonomous navigation, deep learning algorithms to identify and map contaminated areas, and ultraviolet light for effective decontamination. Its efficacy is validated through simulations and studies, showing its potential to enhance infection control measures in high-density BEs.

The application of data analytics in infection control is further proposed by Li et al. (2021), using Building Information Modeling (BIM), occupancy data, and pathogen transmission models to identify high-risk areas and optimize cleaning protocols. Key strategies include frequent surface disinfection, with five daily cleanings reducing pathogen reproduction rates by over 50%, enhanced hand hygiene practices, occupancy management to minimize contamination risks, and tailored cleaning schedules for high-traffic areas, like classrooms. A web-based system facilitates real-time risk communication, enabling proactive adjustments to facility usage and hygiene protocols based on localized contamination patterns.

Briefly, the evidence underscores the necessity of integrating stringent sanitation, antimicrobial materials, environmental modifications, robotic technologies, and data-driven strategies to reduce fomite-mediated disease transmission.

The selection of chemical disinfectants within water systems significantly influences the persistence of mycobacterial species (Donohue and Mistry, 2024). Donohue and Mistry (2024) discuss the importance of the disinfectant choice and its corresponding residual concentration in the management of mycobacterial proliferation within hot water systems, to effectively safeguard public health in BEs. Although chlorine effectively diminishes mycobacterial detections, its high reactivity results in rapid dissipation at elevated temperatures. Conversely, chloramine, characterized by its lower reactivity, diminishes more gradually under heat; however, efficient microbial control depends on extended contact times, and it is less efficacious against multiple waterborne pathogens.

In the same way, Pacheco-Torgal et al. (2021) assert that ttemperature regulation within water systems is a critical factor, with hot water systems being maintained above 55 °C to inhibit Legionella proliferation. Routine flushing of stagnant water and periodic disinfection using chlorine-based or alternative biocidal treatments also reduce microbial colonization in pipes.

Effective management of waterborne pathogen risks requires integrating engineering solutions into plumbing systems. Accordingly, Donohue and Mistry (2024) emphasize that identifying contamination-prone areas—like biofilm formation sites, prolonged water stagnation zones, and extended distances between water heaters and point-of-use taps—enables targeted interventions toward optimizing plumbing design which can help address pathogen proliferation within water systems.

Additionally, utilizing materials such as copper or antimicrobial-coated piping is said to restrict bacterial adhesion and biofilm development by Pacheco-Torgal et al. (2021). Also, implementing real-time microbial monitoring systems can facilitate early detection and prompt remediation of potential microbial hazards within plumbing networks.

Voss (2022) advocates for a unified regional infection prevention and control (IPC) network, enhancing collaboration between acute and long-term care settings. The study emphasizes the role of engineering solutions, including optimized ventilation and water safety measures, in mitigating airborne and waterborne pathogen transmission risks. Furthermore, it explores the integration of AI-powered surveillance systems, real-time diagnostics, and automation to revolutionize IPC by enabling more efficient, data-driven responses to infections.

The role of healthcare workers (HCWs) in infection control is pivotal in preventing waterborne pathogen transmission, especially in clinical settings. Kearney et al. (2024) highlight a survey conducted between 2022 and 2023, which revealed that IPC HCWs exhibited higher awareness than non-IPC HCWs towards environmental transmission risks, and better adherence to liquid waste disposal practices. These findings emphasize the importance of targeted educational interventions to improve waste management practices among non-IPC HCWs.

Conclusively, waterborne transmission poses public health challenges, necessitating a multifaceted approach. Effective chemical disinfection strategies, engineering modifications, collaborative IPC frameworks, and educational programs help reduce pathogen persistence in water systems. As healthcare and BEs evolve, integrating innovative technologies and evidence-based interventions will be essential in safeguarding water quality and preventing disease transmission.

Rodents serve as potential reservoirs for zoonotic pathogens, with their interactions in agricultural and urban environments influencing disease transmission. Mistrick et al. (2024) underscore the importance of investigating zoonotic pathogens in synanthropic rodents and other wildlife, which are essential for delineating their roles as reservoirs and vectors for pathogen spillover at the interface between human and wildlife populations, especially in light of the COVID-19 pandemic which is believed to be spread from bats to an intermediary animal and then to humans (Amin, 2020).

Additionally, the role of animals as potential vectors for hospital-associated pathogens remains understudied as emphasized by Dalton et al. (2020). Guidelines for animal control in healthcare settings are primarily based on human data and need validation in animal populations. A One Health approach—considering human, animal, and environmental reservoirs—is essential for developing evidence-based interventions that largely address microbial transmission risks in healthcare environments.

Syal (2021) examines pandemics, like COVID-19, through a socio-ecological resilience framework, identifying five key urban planning and policy issues impacting disease persistence and management. These include integrating urbanization, land use, animal husbandry, and biodiversity conservation into policies to mitigate zoonotic and climate-related risks; ensuring equitable access to housing, water, sanitation, healthcare, and public spaces to lower vulnerability; maintaining environmental quality to limit pathogen persistence; building redundancy in supply chains and data systems for resilience during disruptions; and promoting decentralized infrastructure management and participatory governance for pandemic responses. The paper emphasizes understanding cities as integrated social-ecological systems for long-term resilience.

In addition, Nhamo et al. (2022) advocate for an integrated water-health-ecosystem-nutrition nexus to mitigate microbiome transmission risks. This approach stresses enhancing resilience and preparedness by addressing factors including sanitation, nutrition, and adaptive capacity, supporting SDG 3 (good health and wellbeing), SDG 6 (clean water and sanitation), and SDG 13 (climate action). By fostering sustainable socio-ecological relationships, this framework aims to minimize pathways for microbiome transmission and promote healthier environments.

To mitigate the numerous microbial transmission risks posed by tsunamis, Mavrouli et al. (2021) emphasizes the importance of implementing disaster preparedness and response plans that address these challenges, including designing evacuation centres, strengthening healthcare facilities, enhancing disease surveillance, and raising awareness about preventive measures and the importance of vaccination.

Thus, pathogen transmission via non-traditional vectors demands a holistic, interdisciplinary approach. Surveillance, urban planning, hospital infection control, and sustainable public health strategies collectively contribute to mitigating these risks. Strengthening these measures ensures long-term resilience against emerging infectious threats.