Room Ventilation Research Articles

Supraglottic airway in neonatal porcine model.

Positive pressure ventilation (PPV) in the delivery room is routinely performed using a face mask attached to a ventilation device. In 2023, the Consensus of Science and Treatment Recommendations for neonatal resuscitation stated that a supraglottic airway (SGA) can be used for PPV if resources and training permits. However, there is very limited data on tidal volume (VT) delivery using SGAs. We aimed to compare VT delivery using five ventilation devices (i.e., self-inflating bag (SIB)), T-Piece resuscitator, flow-inflating bag (FIB), NextStepTM, and Fabian ventilator with an SGA at two compliance levels using a neonatal piglet model. Randomized crossover experimental animal trial using 10 mixed-breed neonatal piglets (1-3 days; 1.8-2.4 kg). Piglets were anesthetized, SGA placed, instrumented, and randomized to PPV for one minute with SIB with or without a respiratory function monitor (RFM), T-Piece resuscitator ± RFM, FIB ± RFM, NextStepTM, and Fabian Ventilator at two compliance levels. Compliance changes were achieved by placing a wrap around the piglets' chest and tightening it. Our primary outcome was targeted VT delivery of 5 mL/kg at 0.5 and 1.5 mL/cmH2O lung compliance. At 0.5 mL/cmH2O compliance, mean(SD) expired VT with the NextStepTM was 5.0(0.1)mL/kg compared to Fabian 5.1(0.2), SIB 6.3(1.8), SIB + RFM 5.3(0.8), T-Piece 5.9(1.5), T-Piece+RFM 5.5(0.6), FIB 7.7(1.8), FIB + RFM 8.5(2.9)mL/kg. At 1.5 mL/cmH2O compliance, mean(SD) expired VT with the NextStepTM was 5.1(0.2)mL/kg compared to Fabian 5.1(0.2),SIB 11.6(3.4), SIB + RFM 7.1(1.8), T-Piece 9.8(1.8), T-Piece+RFM 7.9(1.3), FIB 12.6(3.2), FIB + RFM 9.2(1.4)mL/kg. The NextStepTM provides consistent VT during PPV with little variation despite compliance changes. Clinical studies are warranted. Current guidelines recommend fixed peak inflation pressure in resuscitation, linked to lung and brain injury. The NextStepTM Neonatal Resuscitator, a cost-effective device, offers volume-targeted positive pressure ventilation with consistent tidal volumes delivery. With two different compliances, the NextStepTM Neonatal Resuscitator delivered a consistent tidal volume similar to a mechanical ventilator. The NextStepTM Neonatal Resuscitator outperformed self-inflating or flow-inflating bags and T-Piece resuscitators to deliver targeted tidal volumes. The NextStepTM Neonatal Resuscitator could be an alternative ventilation device for neonatal resuscitation.

Desktop 3D printers in the workplace: use, emissions, controls, and health

Abstract Desktop three-dimensional (3D) printers are used in businesses, schools, and colleges, and are generally of an unenclosed design which may give rise to injuries or inhalation exposure to emissions of small particles (<1 µm) and volatile organic compounds (VOCs). The aim of this work was to explore the health risks related to the use of desktop 3D printers in workplaces in the United Kingdom. A digital survey on the use of desktop 3D printers was completed voluntarily and anonymously between February and June 2023, receiving 146 responses. The most common technology and material used for printing were “filament deposition” and “polylactic acid,” respectively. The median number of printers an organisation had in use in one room was 2. A median of 10 people could be in the room during printer operation. A range of finishing techniques were reportedly applied to the printed object including the use of hand tools and solvents. General room ventilation was the most common exposure control measure stated. Measurements of airborne particles and VOCs were taken at 2 sites: a university and an engineering workshop. Airborne particle number concentrations (<1 µm) did not significantly increase above background levels when the printers were operating at either site. At the university, where there was the largest number of printers in operation, some VOCs could be attributed to the printing process; however, concentrations remained low. Evidence of associated respiratory symptoms was gathered by asking volunteers at the 2 sites visited to complete a questionnaire. Seventeen volunteers across the 2 sites completed the survey. None stated that they had ever experienced acute symptoms from working with 3D printers. However, they did report symptoms which included tiredness, dry/cracked skin, headache, itchy/runny nose, and a cough, with some stating that these improved on their days off. Overall, limited evidence from published literature and this study suggests that exposure to desktop 3D printing emissions could be associated with short-term respiratory health symptoms. However, static measurements in 2 workplaces where multiple desktop 3D printers were in use did not show airborne particle number concentrations in the room rising above background levels and concentrations of measured VOCs were all low. These findings may be due to effective ventilation and other control measures which over half of the workplaces surveyed stated that they had in place.

The impact of gasping versus apnea on initial heart rate and response to positive pressure ventilation in the delivery room following interruption of placental blood flow.

The impact and/or significance of gasping or apnea on cardio-respiratory status at birth remains unclear. The study objectives were to determine in infants presenting with gasping or apnea in the delivery room, initial heart rate (HR), responses to positive pressure ventilation (PPV), time to onset of spontaneous respirations, and the relationship of these responses to 24-hour outcome (death/survival) METHODS: Observation study undertaken in a rural setting involving late preterm and term newborns who gasped (n=126) or were apneic (n=105) at birth and received PPV had HR and respiratory parameters continuously measured and were video recorded. Apneic (12.3 %) versus gasping infants (5.7 %) were 7.2-fold more likely to die in the first 24 h (p = 0.01) and 2.8-fold more likely to die (p = 0.047) by 7 days. Initial HR was higher in gasping versus apneic infants (122 vs 105 bpm) (p = 0.01). Time to initiate breathing after starting PPV was significantly shorter in gasping versus apneic infants. No differences in applied peak inflation pressure, tidal volume, end tidal CO2, or resuscitation duration were noted. Of infants who died versus survivors, a HR < 100 bpm was observed more often in both gasping and apneic infants (p = 0.01) CONCLUSIONS: Infants who present with gasping versus apnea are less likely to die; apneic infants are more likely to die within the initial 24 h. Gasping versus apneic infants had a higher initial HR, were less likely to have a HR < 100 bmp and initiated spontaneous respiratory effort sooner after PPV. These findings are consistent with experimental and adult observations that suggest gasping appears critical to survival if PPV is initiated in a timely manner.

Diffusion characteristics of re-suspended PM2.5 within a radiant floor heating room under various ventilation modes

Few studies have revealed the effects of re-suspension of particulate matter deposited by radiant floor heating on indoor environments. The present study utilized Computational Fluid Dynamics (CFD) to investigate the impact of radiant floor heating and ventilation mode on indoor airflow patterns, as well as the dispersion and migration of re-suspended particulate matter, based on a turbulence model validated by an environmental test cabin. The Archimedes number (Ar) was employed to represent the strength of interaction between the thermal buoyancy force generated by floor radiation and the inertial force of the supply airflow. The results indicates that as Ar increases, the supply airflow exhibits a downward deflection, thereby forming a stable vortex below to prevent the diffusion of heat and re-suspended PM2.5 generated from the heated floor. As the Ar increases, the re-suspended PM2.5 deposited on the surrounding walls increased significantly, and the indoor PM2.5 concentration gradually decreased. When the Ar exceeds 6.03, the increase in Ar will no longer affect the indoor re-suspension PM2.5 diffusion, deposition characteristics, and removal efficiency. Therefore, it is recommended the critical Ar (Arcrit) of 6.03 for a radiant floor heating room under various ventilation modes, beyond which the indoor flow structure and distribution characteristics of re-suspended PM2.5 no longer change with increasing Ar. This study is helpful to further understand the diffusion and distribution characteristics of re-suspended particulates in floor heating and ventilation rooms, and provide technical reference for improving indoor air quality.

Numerical study of engine room air ventilation systems for landing ship tank class warships in supporting crew comfort and safety

Abstract The air ventilation system is one of the supporting systems in the machinery of a warship. High temperatures in the engine room can lead to an unpleasant atmosphere and, in particular, to heat stress for the operating personnel. This heat stress was caused by the design of the engine room ventilation system not meeting the requirements due to the supply and exhaust fan. Under the given conditions, the air temperature reached 50 °C, higher than the standard 45 °C. Therefore, it was necessary to conduct a thermal analysis and redesign the ventilation system using a 3D CFD (Computational Fluid Dynamic). The parameters included temperature distribution, Hlow distribution, and Hlow velocity in the engine room of the Landing Ship Tank class warship when the engine load reached 50%, 75%, and 100%. The results obtained from the simulation were in the form of quantitative data such as temperature gradients and iso contours of the air in the engine room inside the warship. The data comprised velocity contours, temperature, velocity vectors, streamlines, and particle trajectories in space. The results of the CFD approach showed that the quality of the ventilation system in the engine room inHluences extreme conditions in the engine room.

An Easy-to-Use Tool to Predict SARS-CoV-2 Risk of Infection in Closed Settings: Validation with the Use of an Individual-Based Monte Carlo Simulation.

The dynamics of the SARS-CoV-2 pandemic showed that closed environments, such as hospitals and schools, are more likely to host infection clusters due to environmental variables like humidity, ventilation, and overcrowding. This study aimed to validate our local transmission model by reproducing the data on SARS-CoV-2 diffusion in a hospital ward. We implemented our model in a Monte Carlo procedure that simulates the contacts between patients and healthcare workers in Trieste's geriatric ward and calculates the number of infected individuals. We found the median number of infected workers to be 38.98 (IQR = 7.75), while all patients were infected in most of the simulation runs. More infections occurred in rooms with lower volumes. Higher ventilation and mask-wearing contribute to reduced infections; in particular, we obtained a median value of 35.06 (IQR = 9.21) for the simulation in which we doubled room ventilation and 26.12 (IQR = 10.33) in the simulation run in which workers wore surgical masks. We managed to reproduce the data on infections in the ward; using a sensitivity analysis, we identified the parameters that had the greatest impact on the probability of transmission and the size of the outbreak.

Analysis of the Properties and Thermal Behavior of Low-Temperature Phase Change Materials (PCMs) That Can Be Applied in Heating and Ventilation Systems.

This article analyses the use of low-temperature PCMs in devices supplementing a room ventilation system to prevent the overcooling effect. In this study, the phase change is numerically simulated in an axisymmetric system consisting of two tubes. One is filled with RT11HC with an initial temperature of 0 °C, while air with an inlet temperature of 20 °C flows through the other, heating the PCM and causing it to melt. Calculations are performed using commercial software with the apparent heat method for a system of given dimensions. Spatial distributions of the system temperature and liquid volume fraction at different time moments (from 0 to 120 min) are determined. It is found that the results depended mainly on the method of determining the latent heat. For the beginning of the charging process (t < 40 min), the values of the liquid phase fraction determined by the H and S methods are similar, while the one determined by the G method is definitely higher (even three times at t = 10 min). In turn, the outlet air temperature determined by the S method is lower than that determined by the other methods. The size and shape of the mesh have no significant effect on the results.

Study of thermal and humidity environment and prediction model in impinging jet ventilation rooms based on thermal and moisture coupling

Variations of indoor humidity have significant influence on thermal comfort, calculation accuracy of air-conditioning load and selection of design parameters. As one of the most promising advanced ventilation strategies, impinging jet ventilation (IJV) has received much attention. However, few study concerned its coupled indoor thermal and humidity environment and there is also no complete mathematical model for the IJV to synchronously predict its indoor temperature and humidity distributions. Therefore, this study first simulated the thermal and humidity environment in IJV rooms with considering the coupled thermal and moisture transfer effect. The results demonstrate a significant correlation between temperature and humidity distributions in IJV, with a correlation coefficient of approximately 0.4. Then, a simplified theoretical model for predicting temperature and humidity distributions in the IJV was established based on the theory of nodal model, and the key parameters within the model that are influenced by indoor airflow pattern were also identified. Next, the model results were compared with the simulation ones and showed that the proposed model is with a mean absolute error of 0.4 °C for the prediction of temperature distribution and of 0.21 g/kg for the prediction of humidity distribution. These discrepancies are sufficiently minor to validate the accuracy of the proposed model. Last, the potential application value of the proposed model was discussed. Overall, the current study contributes to extend the application of the existing coupled thermal and humidity models to IJV scenarios, and provides a robust theoretical foundation for the more rational design and practical application of the IJV.

The influence of pulsation ventilation on the removal and distribution of gas accumulation areas during gas leakage in industrial plants

A ventilation system with a constant velocity air supply might form airflow stagnant zones in industrial plants, making it challenging to dilute hazardous gas effectively. In this study, a novel ventilation mode called pulsating ventilation, which can potentially dilute the hazardous gas better, was applied in a ventilated room with nozzle air supply. Three different scenarios of gas accumulation were assumed, with the location of gas accumulation situated at the rear, near the floor, and in the corners of the room. Both the distribution of CO2 concentration and the efficiency of reducing the indoor CO2 concentration to the safety threshold were analyzed to evaluate the ventilation performance of pulsating ventilation. The results showed that pulsating ventilation outperformed constant velocity air supply in expeditiously eradicating gas accumulation areas for equivalent total air volumes. When the gas accumulation areas were located at the rear of the room, close to the floor, and in the corner of the room, pulsation ventilation reduced the time for the indoor CO2 concentration to drop to the safety threshold by 36.19%, 27.23%, and 36.25%, respectively. Holding the period constant, an increased amplitude correlated with a swifter decrease in peak pollutant concentration. Except for the case where the gas accumulation areas are close to the floor, when the amplitude is constant, the larger the period, the faster the peak concentration in the gas accumulation areas decreases.

Discrete-event modeling of human behavior for spread of diseases on university campuses

The COVID-19 pandemic has highlighted the importance of defining sound policies to make attending workplaces safely. Sometimes, deciding on different policies is challenging as this highly depends on the behavior of the individuals. This research introduces a Discrete Event-based methodology and a prototype implementation to study such policies, including human behavior along with information about the workplace layout and building characteristics such as ventilation rate or room capacity. The method is based on a combination of agent-based models, diffusion processes and discrete-event simulation. We exemplify how to use this method using a case study based on Carleton University’s Campus, in which we use the methodology and tools to study the effect of ventilation, as well as the application of a policy where sick students are denied entry to the campus on the number of disease cases on campus.

Dietary habit and lifestyle of postpartum women in South China: a mixed methods research

ObjectiveTo investigate the dietary and hygiene behaviours and influencing factors of women during the puerperium in South China.DesignA cross-sectional study.SettingThree tertiary hospitals in Guangdong Province, ChinaParticipantsFrom November 2022 to March...

Development of operable modular louvers Sited in a single-sided ventilated room through 3D parametric optimization

The current design practices of buildings to respond to environmental inputs have led to operable envelopes with external louver blinds systems. The key aspect of any openable louver flap design is to optimize inlets that might induce ventilation for occupants with low indoor airflow. Computational Fluid Dynamics (CFD) in 3D parametric modeling investigated the influence of openable louver inlet geometries (right trapezoid) and positions in a ventilated room. A single-sided ventilated room designed with two mirrored split blocks of inlets attached to that wall perpendicular to the wind was employed for this study. Twenty-eight different inlet shape geometries with their cross-sectional changes were investigated. In addition, the inlets' rotation, orientation, and elevation differences were also studied. Wind tunnel experiments were conducted to measure airflows inside the model room to validate the CFD simulations. A discernible impact was observed when the inclined side of the right trapezoid was oriented upward or downward, where inlet flaps open to the sides of the window. The mean air velocity in the ventilated room becomes more than double when inlet flaps open to the sides of the window, where the elevation difference in the inlet blocks introduces the pressure difference compared to no elevation difference in inlets. This study guides into refining an operable modular louver design to enhance air circulation and natural ventilation in dwelling spaces.

A Numerical Evaluation of Airborne Transmission Control through Saliva Modification

The present study explored the relationship between airborne transmission and the saliva fluid properties of a human sneeze. Specifically, we aimed to understand if altering the saliva and its relationship to droplet breakup and stability can affect its transmission characteristics. The study aimed to answer this question using computational fluid dynamics, specifically, a hybrid Eulerian–Lagrangian model with a Spalart–Allmaras, detached eddy simulation turbulence model. The effort focused on a scenario with a sneeze event within a ventilated room. The study found that for sneezes, secondary breakdown processes are important. Thicker saliva that increased the Ohnesorge number displayed a clear resistance to aerosolization due to stabilized secondary breakup, leading the bulk of the drops having high settling rates that are less likely to drive airborne transmission. For instance, the use of xanthum gum, which increased the saliva viscosity by 2000%, reduced the formation of aerosols. Additionally, another class of modifiers that reduce saliva content was studied, which was also effective in reducing airborne transmission drivers. Zingiber, which reduced the saliva content, reduced the formation of aerosols. However, when considering the overall reduction in droplet volume, saliva modifiers such as cornstarch, xanthum gum, and lozenges increased the mean droplet size by 50%, 25%, and 50%, respectively, while reducing the overall droplet volume by 71.6%, 71.2%, and 77.2%, respectively. Conversely, Zingiber reduced the mean droplet size by 50% but increased the overall droplet volume by 165.7%. Overall, for this type of respiratory event, this study provides insight into the potential for modifying saliva characteristics that may impact airborne transmission and could introduce new tools for reducing airborne pathogen transmission.

Numerical study using the finite volume method on the thermal and energy performance of a regulated underfloor heating system incorporating PCM in a ventilated room

A physical model is performed to assess the thermal and energetic advantages of using PCM in controlling and regulating the indoor temperature of a ventilated room with an underfloor heating system incorporating a PCM. The heating source is regulated to keep the cavity air temperature in a small interval assuring a certain level of comfort without wasting too much energy. By contrasting our numerical results with numerical data from the literature, the suggested model was validated. Physical processes are solved numerically using computational fluid dynamics by a detailed 2D transient simulation integrating real climatic data of Agadir, Tangier and Casablanca. The simulations carried out justified the suitability of using the PCM with Agadir and Casablanca climate types by a saving of heating power reaching 18.80 % and 17.33 %, respectively.

A comparative study on germination of wheat grains with different anthocyanin pigmentation of the pericarp in natural or induced aging.

One of promising areas of wheat breeding is the creation of varieties with a high concentration of anthocyanins in the grain for the production of functional food products. Nonetheless, the question of how these compounds affect seed viability after long-term storage has remained unexplored. A comparative study on seed viability was conducted using a set of near-isogenic lines on the background of spring wheat variety Saratovskaya 29. These sister lines carry different combinations of recombinant DNA regions (on chromosomes 2A and 7D) containing dominant and recessive alleles at loci Pp3 and Pp-D1 (Pp: Purple pericarp), which determine the anthocyanin color of coleoptiles and of the pericarp. Seeds were germinated on two layers of water-moistened filter paper in a climatic chamber at a constant temperature of 20 °C on a 12-hour daylight cycle. During long-term natural storage of the seeds for up to 9 years in a dry ventilated room in Kraft bags at 20 ± 2 °C, the tested wheat samples experienced a loss of seed germination capacity of ~50 %; anthocyanins were found to not participate in the preservation of germination capacity. Nonetheless, anthocyanins contributed to the preservation of seed viability under unfavorable short-term conditions of a temperature rise to 48 °C at 100 % humidity. The accelerated aging test did not predict poor germination capacity after long-term seed storage. The results showed a neutral role of anthocyanins in the maintenance of seed germination capacity for 6-9 years under natural storage conditions at 20 ± 2 °C. A small statistically significant increase in grain germination capacity during natural aging was associated with the presence of a recombinant region containing the Pp-D1 gene on wheat chromosome 7D.

Positive or negative? The pressure control impact in hybrid ventilated hospitals

The outbreak of coronavirus disease 2019 (COVID-19) has had a significant impact on human life. Hybrid ventilated hospitals have emerged as multi-zone sites, necessitating ventilation strategies to mitigate viral concentration. This paper integrates multi-zone infiltration and exfiltration (MIX) model of natural ventilation, spatial flow impact factor (SFIF) model and pollutant concentration model to analyze the inter-zonal impact. Results indicate that elevated outdoor temperature corresponds to an increased influence of rooms on corridors. Adopting mechanical ventilation in rooms diminishes the influence of room pollutants on corridors but exerts minimal impact on other rooms. Mechanical air supply reduces the interaction between corridors, and the reduction is most significant when wind direction is the same as stairwell orientation. The corridors do not affect the upstream rooms when the source is in the corridor. When wind speed is below a threshold, mechanical air supply is recommended; for wind speed reaching this threshold, mechanical air exhaust volumes should be adjusted regarding the wind speed. The study reveals that corridor and room window openings exert disparate effects on corridor concentration under mechanical air supply conditions. All the findings offer valuable insights for selecting ventilation strategies in hybrid ventilated hospitals, with the aim of mitigating COVID-19 transmission.

Airflow and aerosol transport in the hospital isolation zone based on dynamic scenarios

To contain the leakage of viral aerosols, buffer rooms are usually provided in front of isolation wards. However, dynamic events of door movement and healthcare worker (HCW) walking will result in highly concentrated aerosols intruding into the buffer room from the ward, challenging the control of virus transmission risk. In this work, airflow exchange and bioaerosol particle transport between the negative-pressure isolation ward and the buffer room under dynamic scenarios were studied by transient computational fluid mechanics (CFD) simulation, thereby the fate of particles was divided into invasion stage and decay stage. The effects of ventilation pattern and HCW location on the concentration level and attenuation trend of particles were quantitatively analyzed. The results showed that increasing the HCW walking distance could increase the peak particle concentration within the buffer room by 4.5 % during the invasion stage. The effect of the buffer room ventilation layout on air exchange and particle transport was more pronounced than the HCW stay position. In the decay stage, the two more effective ventilation layouts could decrease the complete clearance time of particles and the particle concentration in the breathing zone by 31 % and 42 %, respectively. To reduce the infection risk, bioaerosol levels need to be reduced both in the buffer room and in the HCW breathing zone.

Relationship between Exhaled Aerosol and Carbon Dioxide Emission Across Respiratory Activities.

Respiratory particles produced during vocalized and nonvocalized activities such as breathing, speaking, and singing serve as a major route for respiratory pathogen transmission. This work reports concomitant measurements of exhaled carbon dioxide volume (VCO2) and minute ventilation (VE), along with exhaled respiratory particles during breathing, exercising, speaking, and singing. Exhaled CO2 and VE measured across healthy adult participants follow a similar trend to particle number concentration during the nonvocalized exercise activities (breathing at rest, vigorous exercise, and very vigorous exercise). Exhaled CO2 is strongly correlated with mean particle number (r = 0.81) and mass (r = 0.84) emission rates for the nonvocalized exercise activities. However, exhaled CO2 is poorly correlated with mean particle number (r = 0.34) and mass (r = 0.12) emission rates during activities requiring vocalization. These results demonstrate that in most real-world environments vocalization loudness is the main factor controlling respiratory particle emission and exhaled CO2 is a poor surrogate measure for estimating particle emission during vocalization. Although measurements of indoor CO2 concentrations provide valuable information about room ventilation, such measurements are poor indicators of respiratory particle concentrations and may significantly underestimate respiratory particle concentrations and disease transmission risk.

Assessment on the Exposure of Air, Water and Noise Pollution, and Mental Stress on Preeclamptic Patients of Rajshahi, Bangladesh

Although preeclampsia claims the lives of 70,000 mothers and 500,000 newborns each year worldwide, its origin is still elusive and a number of risk factors such as environmental pollution are not yet addressed properly. In this study, exposures due to the extents of air, water and noise pollution as well as mental stress on preeclamptic patients have been investigated. Using a cross-sectional longitudinal design, 90 women hospitalized with preeclampsia in 7 hospitals of Rajshahi, Bangladesh were considered, of which Rajshahi Medical College Hospital is a tertiary referral hospital. The data were collected by interviewing the patients, physical examinations and merging the patients’ data with British Geological Survey’s groundwater data-sets (n=3,540). For statistical analyses, SPSS software was employed. It was found that most of the patients’ living rooms were within 15 feet from kitchen. Only 10% patients had good room ventilation, while the remaining 90% patients had either moderate or poor room ventilation. Combination of these facts reveals that the preeclamptic patients were subject to moderate CO2 exposure. Since 79% of the preeclamptic patients’ living rooms were below 50 ft from the nearest roads and 84% for 100 ft distance, they would experience noise pollution. Combination of traffic conditions and potential sources of noise pollution revealed that 60% of the preeclamptic patients experienced moderate to intense noise pollution. Groundwater arsenic, calcium, magnesium, iron and sodium concentrations in the patients’ drinking water were higher than WHO guideline values that should favour constipation and mild hypertension. While 70% patients were under high mental stress and 24% under very high mental stress, only 6% patients had moderate mental stress. It is concluded that air, water and noise pollution, and mental stress are potential risk factors of preeclampsia.

A coronavirus disease 2019 outbreak in a residential living facility with suboptimal ventilation in resident rooms

We report a large outbreak of severe acute respiratory syndrome coronavirus 2 in a residential living facility. Measurements of carbon dioxide levels, aerosol particle clearance, and airflow were used to identify and remediate areas with suboptimal ventilation. A simple intervention involving continuous operation of bathroom fans was effective in significantly improving ventilation in resident rooms.