Air Change Research Articles

A New Tailored Approach to Calculate the Optimal Number of Outdoor Air Changes in School Building HVAC Systems in the Post-COVID-19 Era

Air conditioning systems can play a positive or negative role in the spread of COVID-19 infection. The importance of sufficient outdoor air changes in buildings was highlighted by the World Health Organization, therefore these should be guaranteed by mechanical ventilation systems or adequate air conditioning systems. The proposed case study concerns the optimal number of outdoor air changes to limit COVID-19 contagion for a school building in Central Italy. The Wells–Riley model is used to assess the risk of airborne infection, while energy consumption is calculated by a dynamic energy simulation software. The scope of the paper offers an innovative method to define the optimal ventilation strategy for the building’s HVAC system design to reduce the risk of infection with limited increases in energy consumption and greenhouse gas emissions. Results show that the desirable approach is the one in which the same low value of contagion risk is set in all rooms. This new approach results in significant energy savings, compared to the most common ones (setting the same high outdoor air rates for all rooms) to counteract the risk of infection. Finally, the zero-emission building target is verified by introducing a suitable photovoltaic system to offset pollutant emissions.

Effect of climate change of the quality of Citrus fruit produced in South Africa

Climate change is an observed reality with a significant impact globally. South Africa is not immune to this phenomenon. Like the rest of the world, South Africa experiences rise in mean air temperature and changes in rainfall trends. Since plant systems are influenced by weather, it is expected that climate change will have an effect on the production and quality of fruit. The objective of this study was to determine the impact of climate change on the quality of citrus fruit produced in South Africa. In conducting the study, historical fruit quality data was collected from packhouses in the Eastern and Western Cape provinces of South Africa over a period of 12 and 8 years respectively. Trend analysis was done on the data to determine whether there is a trend that can be observed over the period of data collection. The total soluble solids of fruit showed a marginal increase over the period of observation. Titratable acidity showed a marginal decrease. The incidence of sunburn on fruit seemed to increase over time. Other disorders like decay, creasing and oleocellosis did not show a definite trend of increasing or decreasing over time. Rind disorders seemed to decrease during the period of observation. This report discusses how the observed trends were influenced by changes in rainfall and temperature over the period of observation. It is then concluded that in this case study, the impact of climate change was not very profound and it had both negative and positive effects. The current results point toward a bleak future for citrus producers. To remain profitable, it may be necessary for producers to invest in climate change adaptation technologies. Key words: Climate change, citrus fruit, fruit quality, oleocellosis, titratable acidity

Sessile oak (Quercus petraea [Matt.] Liebl.) and its adaptation strategies in the context of global climate change: a review

Abstract This paper provides characteristic and a comprehensive overview of the adaptation strategies of sessile oak (Quercus petraea [Matt.] Liebl.) in the context of global climate change (GCC). The GCC is primarily manifested by increasing air temperatures and changing precipitation distribution. It poses a significant challenge to tree species including sessile oak, affecting its capacity for adaptation and survival. Despite the challenge, sessile oak shows significant drought tolerance due to its deep-reaching root system, which allows the tree to use available water more efficiently. Other adaptive strategies include the establishment of mixed stands that increase the resilience and biodiversity of the ecosystem. Adjustments of stand density through tending interventions play a significant role, helping to improve the stress resistance of stands. Additionally, coppice forest cultivation is applied on extremely dry sites. The sessile oak is also significant for its ecological plasticity – its ability to thrive on versatile soil and climatic conditions makes it a promising tree species for future forest management. Mixed stands with sessile oak and other tree species can enhance the ecosystem services of forests and also increase their endurance to GCC events. However, sessile oak faces several challenges, including the increasing risk of damage from pests and pathogens that require targeted measures for its protection and sustainable cultivation. The literature review suggests that a comprehensive understanding of sessile oak’s ecological requirements and interactions with the environment is crucial for its successful adaptation to GCC and the formulation of effective strategies for its protection and use in forest management.

A CFD Methodology for the Modelling of Animal Thermal Welfare in Hybrid Ventilated Livestock Buildings

Computational fluid dynamics (CFD) may aid the design of barn ventilation systems by simulating indoor cattle thermal welfare. In the literature, CFD models of mechanically and naturally ventilated barns are proposed separately. Hybrid ventilation relies on cross effects between air change mechanisms that cannot be studied using existing models. The objective of this study was to develop a CFD methodology for modelling animal thermal comfort in hybrid ventilated barns. To check the capability of CFD as a design evaluation tool, a real case study (with exhaust blowers) and an alternative roof layout (with ridge gaps) were simulated in summer and winter weather. Typical phenomena of natural and mechanical ventilation were considered: buoyancy, solar radiation, and wind together with high-speed fans and exhaust blowers. Cattle thermal load was determined from a daily animal energy balance, and the assessment of thermal welfare was performed using thermohygrometric indexes. Results highlight that the current ventilation layout ensures adequate thermal welfare on average, despite large nonuniformity between stalls. The predicted intensity of heat stress was successfully compared with experimental measurements of heavy breathing duration. Results show strong interactions between natural and mechanical ventilation, underlining the need for an integrated simulation methodology.

Interacting impacts of hydrological changes and air temperature warming on lake temperatures highlight the potential for adaptive management.

Globally, climate warming is increasing air temperatures and changing river flows, but few studies have explicitly considered the consequences for lake temperatures of these dual effects, or the potential to manage lake inflows to mitigate climate warming impacts. Using a one-dimensional model, we tested the sensitivity of lake temperatures to the separate and interacting effects of changes in air temperature and inflow on a small, short-residence time (annual average ≈ 20days), temperate lake. Reducing inflow by 70% increased summer lake surface temperatures 1.0-1.2°C and water column stability by 11-19%, equivalent to the effect of 1.2°C air temperature warming. Conversely, similar increases in inflow could result in lake summer cooling, sufficient to mitigate 0.75°C air temperature rise, increasing to more than 1.1°C if inflow temperature does not rise. We discuss how altering lake inflow volume and temperature could be added to the suite of adaptation measures for lakes.

Assessment of genotoxicity of air pollution in urban areas using an integrated model of passive biomonitoring

Atmospheric pollution is a major public health issue and has become increasingly critical for human health. Urban atmospheric pollution is typically assessed through physicochemical indicators aligned with environmental legislation parameters, providing data on air quality levels. While the effects of pollution on sensitive organisms serve as a warning for public health decision-makers, there remains a need to explore the interpretation of environmental data on pollutants. The use of species adapted to urban environments as sentinels enables continuous and integrated monitoring of environmental pollution implications on biological systems. In this study, we investigated the use of the plant species Tradescantia pallida as a biomonitor to evaluate the genotoxic effects of atmospheric pollution under diverse vehicular traffic conditions. T. pallida was strategically planted at the leading urban intersections in Uberlândia, Brazil. During COVID-19 pandemic lockdowns, we compared indicators such as physical, biological, and traffic data at different intersections in residential and commercial zones. The reduction in vehicular traffic highlighted the sensitivity of plant species to changes in air and soil pollutants. T. pallida showed bioaccumulation of heavy metals Cd and Cr in monitored areas with higher traffic levels. Additionally, we established a multiple linear regression model to estimate genotoxicity using the micronucleus test, with chromium concentration in the soil (X1) and particulate matter (PM) in the atmosphere (X2) identified as the primary independent variables. Our findings provide a comprehensive portrait of the impact of vehicular traffic changes on PM and offer valuable insights for refining parameters and models of Environmental Health Surveillance.

How Does Personal Hygiene Influence Indoor Air Quality?

Humans are known to be a continuous and potent indoor source of volatile organic compounds (VOCs). However, little is known about how personal hygiene, in terms of showering frequency, can influence these emissions and their impact on indoor air chemistry involving ozone. In this study, we characterized the VOC composition of the air in a controlled climate chamber (22.5 m3 with an air change rate at 3.2 h-1) occupied by four male volunteers on successive days under ozone-free (∼0 ppb) and ozone-present (37-40 ppb) conditions. The volunteers either showered the evening prior to the experiments or skipped showering for 24 and 48 h. Reduced shower frequency increased human emissions of gas-phase carboxylic acids, possibly originating from skin bacteria. With ozone present, increasing the number of no-shower days enhanced ozone-skin surface reactions, yielding higher levels of oxidation products. Wearing the same clothing over several days reduced the level of compounds generated from clothing-ozone reactions. When skin lotion was applied, the yield of the skin ozonolysis products decreased, while other compounds increased due to ozone reactions with lotion ingredients. These findings help determine the degree to which personal hygiene choices affect the indoor air composition and indoor air exposures.

Heat recovery of decentralised façade units: A case study

Indoor air quality affects the health of the premises' users and the efficiency of their work. Sealing the building envelope to reduce the demand for thermal energy reduces the number of air changes. One of the solutions that improve indoor air conditions is decentralised façade units to alternate air supply and exhaust. An important issue is the implementation of heat recovery in this type of solution, the aim of which is to reduce the energy consumption of ventilation and air conditioning systems. There is no description of research in the literature on the use of various methods of heat accumulation in façade units. The available descriptions are limited to aluminium, ceramics, and PCM. The novelty presented in this study is the use of gravel and gypsum as materials for storage in heat recovery exchangers.The objective of the article is to identify important factors influencing the efficiency of heat recovery, the parameters of air flowing through decentralised façade units, and the internal air temperature.The heat recovery exchanger located in a decentralised façade unit for alternating air supply and exhaust was analysed. Two exchanger filling configurations were tested: gravel and gypsum. Three variants of cycle length settings were analysed: 2 min, 6 min, and 10 min. Airflow, temperature before and after the heat recovery exchanger, and temperature inside and outside the room were measured.Research showed that the type of material that fills the heat recovery exchanger is more important than the duration of the cycle or airflow. The heat recovery efficiencies achieved for gypsum are 72 – 87 %, and for gravel 92 %. The material used and the setting do not affect the temperature values before the heat exchanger. The setting has no significant impact on the temperature after the heat recovery exchanger and on the indoor air temperature. In turn, the type of material significantly affects the values of these parameters.

Ventilation improvement for effective protection of healthcare workers in negative pressure airborne infectious isolation room from viral aerosols

A negative pressure airborne infectious isolation room (AIIR) is the primary healthcare air contamination control system used for the treatment of severe respiratory infectious patients. Effects of the ventilation system configuration and conditions on airflow pattern, aerosol distribution and ventilation performance were investigated using computational fluid dynamics (CFD). The field measurement by SARS-CoV-2 environmental surface test was also conducted. The cycle threshold values from transcription polymerase chain reaction (RT-PCR) method showed inverse relation to the simulated number of particles trapped on the surfaces indicating a good agreement. Modification of the present AIIR to have alignment between air inlet and outlet where the aspect ratio of the air outlet, Width (W): Height (H) = 1:1 (Improved case: IC#1) showed a 78 % reduction of aerosol concentration in healthcare workers (HCWs) zones. Aerosol concentrations were increased when the openings of the air outlet were enlarged. Addition of air outlet led to large swirling air, resulting in more aerosols being trapped and suspended in the air. Results suggested that AIIR with alignment air inlet on the ceiling and air outlet at the wall over the patient's head with W:H = 1:1 be the most suitable configuration to maximize the ventilation performance and minimize exposure risk to aerosolized viral infection for HCWs. Air change rate plays a more important role than the differential pressure on the removal efficiency. The differential pressure value should be at least −2.5 Pa and the air supply rate 12 ACH for effective protection of HCWs in the negative pressure AIIR.

Temperature dependence of constant current hot-film sensors: Investigation with application to temperature correction for wall-shear stress measurements

Hot-film sensors measure wall-shear stress based on the forced convective heat transfer. Variations of ambient temperatures lead to significant measurement errors for such thermal sensors and must be corrected for sometimes. Although methods for correcting the temperature shifts of hot-film sensors driven in constant temperature or constant voltage mode have been suggested over the years, the temperature dependence and relevant correction schemes of constant current mode of operation are still open questions. In this study, temperature dependence characteristics of constant current hot-film sensors are investigated within relatively large temperature changes in air and water channel flows (28 °C and 16 °C, respectively). The specific property of constant overheat ratios under varying temperatures for constant current driving mode is found and a quite simple temperature correction function is derived on that basis to eliminate the temperature dependence without any assumed heat transfer correlation. With the correction function, the data at different ambient temperatures are collapsed to single curves with high R2 factors over 0.99, typically. Furthermore, after correction, the relative errors of the measured wall-shear stress are reduced to within ±6 % of the true values. It will then enable the constant current hot-film sensors to calibrate at only one ambient temperature instead of a multiple range of temperatures as with many other schemes, which is more practical and convenient.

In situ air change rate estimation from metabolic CO2 measurement. Summer experimental campaign in a single-family test house

Night ventilation is one of the most promising approaches for reducing the cooling-energy consumption of buildings while improving the summer thermal comfort of occupants. More accurate measurement of the air change rate (ACR) through window openings may help promote this approach. Indeed this is still an active research topic that requires well-controlled experimental data. This article aims to expand the application scope of the tracer gas methodology for dynamic estimation of ACR in residential buildings. Controlled inputs, such as human metabolic CO2 emissions and various window-opening configurations, are chosen to represent the actual use of a single-family house during the cooling season. The measurement dataset – including weather on site, wind on the walls, indoor air speed, temperature, relative humidity, CO2 concentration at various positions and at a time resolution of 1 min – is processed for sharing. Wind fluctuation on the external wall emphasizes the dynamic nature of ACR. Indoor temperature and CO2 concentration measurements showed a mean spatial heterogeneity of 1.0 °C and 625 ppm, respectively. Indoor CO2 levels are low (<2000 ppm), which is a limitation in the use of the tracer gas equation. Thus, the potential of the dataset for dynamic ACR estimation is discussed by introducing and analyzing two indicators. Finally, the ability of the dataset to compute dynamic ACR is demonstrated through deterministic solving of the tracer gas equation.

Parametric study and optimization on exhaled particle dispersion in a ward heated by impinging jet ventilation using orthogonal-based grey relational method

During the heating season with high-frequency infection events, an appropriate ventilation method is critical to a healthy hospital environment. In this study, impinging jet ventilation (IJV) was proposed to reduce cross-infection risk in a two-bed ward for winter heating. An Eulerian-Lagrangian approach validated by experimental data was employed to simulate exhaled particle dispersion. Using a full factorial design method, under air changes per hour (ACH) of 6–15 h−1 and supply air temperature (Ts) of 24–30 °C, the effects of supply air parameters on particle dispersion was analyzed. A correlation model was subsequently established to delineate the relationship between supply air parameters and particle elimination. With an orthogonal-based grey relational method, this study compared the contribution and significance of supply air parameters and two uncontrollable factors (i.e., source location and outdoor air temperature), and then optimized the supply air parameters of IJV. The results indicated that the contribution percentage of supply air parameters was higher than 70 % for particle removal and residence time. With an appropriate supply air parameter, the airflow of IJV could comply with human body plume, enhancing removal of fine particles (≤20 μm). However, with a low Ts (lower than 26 °C) or an excessive ACH (more than 12 h−1), the number of fine particles moving upwards might be reduced. To achieve a better performance in preventing cross-infection, ACH and Ts of IJV were recommended to be set at 9 h−1 and 28 °C, respectively. The findings were expected to provide guidance for ward ventilation design.

Source tracing the bedroom bacteria across different climate zones in China during the heating season

Approximately 1/3 of people's time is spent in bedrooms. Regulating the health implications arising from the bedroom bacterial community demands an in-depth understanding of both the bacterial composition and the influential factors. This study employed high-throughput 16 S rRNA amplicon sequencing to characterize the bacterial community in 23 residential bedrooms across five climate zones in China. Our findings reveal that the bacterial richness and diversity were highest in the Hot-Summer-Cold-Winter (HSCW) zone, possibly due to its lowest indoor temperature during the heating season. Employing an advanced source tracing algorithm, we identified ventilation rate as the dominant factor affecting outdoor bacterial presence, with each additional air change per hour (ACH) increasing the outdoor bacterial abundance by 13.7 %. The integumentary system was the largest contributor to the occupant-associated bacteria, particularly in the residences located in the Severe Cold and Cold zones. Our study provides valuable insights into the diverse bacterial communities in residential bedrooms across various climate zones in China, elucidating the key factors and sources that contribute to shaping these complex microbial ecosystems.

Evaluation of cooling energy saving and ventilation renovations in office buildings by combining bioclimatic design strategies with CFD-BEM coupled simulation

Bioclimatic design knowledge and measures, including passive techniques and natural ventilation cooling, are urgently for building renovation to mitigate global warming. The performance of indoor airflow, energy, economic, and environmental aspects has been researched separately. However, developing a comprehensive framework to investigate bioclimatic strategies under the impact of climate change is challenging. This study aims to integrate bioclimatic design strategies with a coupled simulation approach using Fluent and EnergyPlus to evaluate retrofitting techniques for a single-room office in a university building in a hot summer and cold winter climate. A bioclimatic analysis was conducted to recommend cost-effective passive cooling strategies, including natural ventilation and window shading systems. Two passive measures, changing window types and furniture layouts, were included in renovation packages. Results indicated that the empty model is not valid compared to the fully furnished model when calculating room air change per hour (ACH). Natural ventilation was the most cost-effective strategy to mitigate climate change, with a net present value (NPV) ranging from USD 135.09 to 402.81 over 30 years. However, a higher ACH did not ensure a longer natural ventilation period. By changing the top-hung window to a vertical sash and implementing a movable furniture layout, can achieve better ventilation efficiency. The installation of window vertical shadings had the highest annual emission savings by 2080, while it performed negative economic viability in both the present and the 2050 climates. This research demonstrated how combining bioclimatic measures with a co-simulation approach can offer a thorough evaluation of building energy retrofitting. The results could support architectural and engineering design by integrating bioclimate measures to identify the most effective strategies.

Analyzing temperature distribution in cable cabins within utility tunnels: Developing effective ventilation strategies for local thermal environment enhancement

Convection heat transfer between the cables and the air in the cable cabin of the utility tunnel can lead to high temperatures in the cable cabin. High-temperature environments may cause the performance of cable systems to degrade, threatening the stability of the city's power supply. Increasing ACH (air changes per hour) alone could not effectively improve the high temperature at the end of the cable cabin. This paper employed numerical simulations and rigorous experimental validation to study the summer temperature field of cable cabins in Xi'an. An innovative disturbance ventilation method was proposed to alleviate the high-temperature phenomenon. The results indicated that as the wind flow length increases, the temperatures rise rapidly with the distance increased, resulting in a stable high-temperature area at the end of the cable cabin and the high-temperature air accumulated at the top by thermal buoyancy. When the ACH (air changes per hour) increased from 2 to 6, the temperature field range decreased by 3.25–6.39 %, and the variance decreased by 6.03–14.42 %. After installing a disturbance fan at the beginning of the stable zone, the temperature field in the cable cabin was fully mixed. Compared to directly increasing the ACH, the temperature field range decreased by 20.65–44.76 %, and the variance decreased by 40.28–64.47 %. The introduction of a disturbance fan could thoroughly mix the air and effectively improve the local thermal environment in the cable cabin. This study contributed to the optimization of cable cabin ventilation strategies.

Effectiveness of natural ventilation through single-sided window opening in air-conditioning rooms

Since many buildings are not equipped with fresh air systems, many people open windows to allow for natural ventilation while the air conditioner is running. However, prolonged window opening may cause unnecessary energy consumption. Additionally, the diverse ways of window opening lead to significant variations in indoor airflow distribution, consequently impacting ventilation efficiency. Therefore, this study used field experiments and computational fluid dynamics (CFD) to determine the air exchange efficiency and air change rate of single-sided natural ventilation in air-conditioning rooms by fitting the decay curves of tracer gas. CFD simulation was performed using the unsteady Reynolds-averaged Navier-Stokes (RANS) model to examine how window openings affect the room’s air distribution, and the computed indoor CO2 concentration was compared to the corresponding field experiment data. The results show that natural ventilation through the window opening induced constant heat and mass exchange between indoor and outdoor air, which caused extra cooling losses but was globally effective in eliminating indoor contaminants. The air exchange efficiency is influenced to varying degrees by factors such as the air supply register’s position, window opening percentage, and window opening position. The air supply register’s position exerted the most significant impact at 46.45%. Efficient indoor-outdoor air exchange can be achieved by opening windows intermittently. When the window is opened from one side and the opening percentage is 100%, the indoor environment can be improved by opening the window for about 10 min every 39 min for X-direction air supply and about 7 min every 39 min for Y-direction.

Effectiveness of do-it-yourself air cleaners in reducing exposure to respiratory aerosols in US classrooms: A longitudinal study of public schools

Poor indoor air quality (IAQ) harms student health and cognitive performance. Air filtration serves to reduce concentrations of particles in indoor environments. We have characterized the performance of Do-It-Yourself air filtration units in primary and secondary public schools in Arizona and Connecticut during the 2022-23 school year. We monitored indoor air quality in 53 classrooms across 5 schools in two states over a six-month period. Measurements of decay rates of aerosol particles smaller than 2.5 μm emitted into classrooms during periods with and without the air cleaners allowed for determination of the effective air changes per hour (ACHe) and apparent clean air delivery rate (CADR). We found an average Clean Air Delivery Rate (CADR) of 239 ft3min-1 (range of 101–355 ft3min-1) across a diverse sample of geographic locations and building types, including naturally and mechanically ventilated learning environments. We observed a 43.3 % reduction in PM2.5 concentrations and 30.6 % reduction in PM10 concentrations in mechanically ventilated classrooms. This study suggests that the addition of a DIY air filtration unit effectively improves indoor particle control in school classrooms across a diverse sample of geographic locations and building types.

Tin Halide Perovskite Epitaxial Films on Gold Surfaces: Atomic Structure and Stability

AbstractTin‐based halide perovskite solar cells can be efficient and environmentally friendly substitutions to lead‐based halide perovskite solar cells, but they have a drawback due to oxidation from Sn2+ to Sn4+. Using vacuum deposition, epitaxially aligned CsSnBr3 ultrathin films are prepared on Au(111) and Au(100) and characterized with scanning tunneling microscopy (STM), low‐energy electron diffraction (LEED), and X‐ray photoelectron spectroscopy (XPS). By co‐evaporation of the precursor molecules CsBr and SnBr2, few monolayers of perovskite are obtained. On Au(111), CsSnBr3 grows in three differently oriented domains due to the hexagonal symmetry of the substrate. On Au(100), which has square symmetry, identical to CsSnBr3, but with about half the lattice constant of the perovskite, a (2×2) superstructure is observed. The perovskite is terminated with the (001) facet showing a square surface structure in agreement with density functional theory (DFT) calculations. Chemical analysis is performed in ultra‐high vacuum (UHV) conditions and no indication of a tin oxidation state higher than Sn2+ is found in the films. However, after exposure to air, rapid and severe changes in the films are observed, highlighting the importance of preparing tin perovskites in a controlled environment to maintain their stability and avoid oxidation‐related issues.

Ventilation performance evaluation of an operating room with temperature-controlled airflow system in contaminant control: A numerical study

This article investigates the efficacy of temperature-controlled airflow systems in modern operating rooms for contaminant control, a critical factor in preventing surgical site infections. We have conducted experimental measurements in an operating room equipped with temperature-controlled ventilation to map the airflow field and contaminant dispersion (airborne particles with diameters ranging from 0.5 to 1 μm). The results were used to validate the computational fluid dynamics code, which was then employed to simulate and examine different conditions, including contaminant release locations and air supply rates. Realizable k-epsilon and passive scalar models were utilized to simulate airflow and airborne particle phases. We assessed the airflow distribution and contaminant dispersion, utilizing indices such as ventilation and air change efficiency scales. The analysis provided quantitative insights into the distribution and removal of contaminants, as well as the speed at which the room air was replaced. Contamination was found to be effectively reduced when contaminants were released near exhaust outlets or under central unidirectional inlets. The presence of the operating table caused a big distortion of the central downward airflow, forming a horizontal air barrier at the periphery. Under this unique interior configuration, an appropriate air supply ratio between central and periphery zones was required to achieve optimal overall ventilation performance.

Improve Cannabis sativa micropropagation through increasing air change rate in photoautotrophic and traditional tissue culture

Micropropagation is essential for pathogen-free plant materials. However, the conventional in-vitro micropropagation approach poses challenges for optimal growth and development. This study enhances Cannabis sativa micropropagation by implementing a photoautotrophic tissue culture with increased air change rates. This method relies exclusively on photosynthesis for carbohydrate synthesis, eliminating the need for exogenous sugar supplementation. To overcome the limitations of conventional in vitro culture, the photoautotrophic culture requires higher air exchange in the vessel to supply CO2 for photosynthesis. The research evaluates the effects of varying air change rates, comparing conventional tissue culture (TC) with photoautotrophic micropropagation (PAM). Nodal explants, each with 3–4 fully expanded leaves, were transferred to PAM or TC media in Magenta boxes, undergoing four distinct air change rate treatments: 0.5 (control), 4.1, 7.9, and 14.5 air change per hour. Magenta boxes were placed under controlled chamber conditions, including a photosynthetic photon flux density of 100 µmol·m−2·s−1, 18-hour photoperiod, 25 °C temperature, 70 % relative humidity, and CO2 concentration of 553 µmol·mol−1; data were collected after a 28-day period. Increasing the air change rate in TC (from 0.5 to 7.9 h−1) and PAM (from 0.5 to 14.5 h−1) resulted in a significant 25.1 % and 146.6 % increase in shoot dry mass, respectively. The number of axillary buds per plant exhibited a linear increase response to increasing air change rates only under PAM; as well as a significant difference between PAM (11.5) and TC (8.3) under an air change rate of 7.9 h−1. Particularly advantageous for PAM was simultaneous root growth, escalating from 5.2 to 44.3 mg as the air change rate rose from 0.5 to 14.5 h−1. Implementing the photoautotrophic culture practice not only accelerated Cannabis micropropagation but also maintained outcomes comparable to traditional sugar-based tissue culture, contributing to cost-effective cultivation practices in the Cannabis and tissue culture industries.