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Mesophyll resistance for CO2 diffusion (rm) is one of the main limitations for photosynthesis and plant growth. Breeding new varieties with lower rm requires knowledge of its distinct components.We tested new method for estimating the relative drawdowns of CO2 concentration (c) across hypostomatous leaves of Fagus sylvatica. This technique yields values of the ratio of the internal CO2 concentrations at the adaxial and abaxial leaf side, cd/cb, the drawdown in the intercellular air space (IAS), and intracellular drawdown between IAS and chloroplast stroma, cc/cbd. The method is based on carbon isotope composition of leaf dry matter and epicuticular wax isolated from upper and lower leaf sides. We investigated leaves from tree‐canopy profile to analyse the effects of light and leaf anatomy on the drawdowns and partitioning of rm into its inter‐ (rIAS) and intracellular (rliq) components. Validity of the new method was tested by independent measurements of rm using conventional isotopic and gas exchange techniques.73% of investigated leaves had adaxial epicuticular wax enriched in 13C compared to abaxial wax (by 0.50‰ on average), yielding 0.98 and 0.70 for average of cd/cb and cc/cbd, respectively. The rIAS to rliq proportion were 5.5:94.5% in sun‐exposed and 14.8:85.2% in shaded leaves. cc dropped to less than half of the atmospheric value in the sunlit and to about two‐thirds of it in shaded leaves.This method shows that rIAS is minor but not negligible part of rm and reflects leaf anatomy traits, i.e. leaf mass per area and thickness. [ABSTRACT FROM AUTHOR]

This article focuses on the influence of occupants on the concentration of contaminants (radon Rn-222 and CO2) as well as the thermal comfort parameters. A series of sensors were placed to measure the concentration of the contaminants, temperature, and relative humidity in the test room at the Institute of Nuclear Physics PAN in Krakow (IFJ PAN), Poland. The test room is an office that is typical of the offices used in the facility. The occupants that used the space kept a detailed diary of their entry, exit, and number of people entering. The results showed that the accumulation of contaminants in such spaces may be severe and risks the health and safety of occupants. The accumulation of CO2 was extremely noticeable and did not diminish to the background level between the re-entry of the occupants to the office. The same was consistent for the radon concentration. The study shows how ventilation methods and small changes in occupant work strategy may influence the contaminant concentration within a test zone. [ABSTRACT FROM AUTHOR]

See also the Commentary on this article by Chater, 243: 503–505. [ABSTRACT FROM AUTHOR]

Various methodologies are used to estimate the impact of changing climatic factors, such as precipitation, temperature, and solar radiation, on crop production and water demand. In this study, the changes in rice yield, water demand, and crop phenology were estimated with varying CO2 concentration and an ensemble of general circulation models (GCMs), using a decision support system for agrotechnology transfer (DSSAT), a crop growth model. The measured CO2 concentration of 400 ppm from the Keeling curve, was used as the default CO2 concentration to estimate yield, water demand, and phenology. These outputs, obtained with the default concentration, were compared with the results from climate change scenarios' concentrations. Further, the outputs corresponding to the ensembled GCMs' climate data were obtained, and the results were compared with the ensembled crop model outputs simulated with each GCM. The yield was found to increase with the increase in CO2 concentration up to a certain threshold, whereas water demand and phenology were observed to decrease with the increase in CO2 concentration. The two approaches of the ensemble technique to obtain final outputs from DSSAT results did not show a large difference in the predictions. [ABSTRACT FROM AUTHOR]

As concerns about indoor air quality increase, air purifiers and fresh air systems are increasingly being used in conjunction with air conditioners in office buildings. To study the synergistic effects of multisystem joint operation on indoor air quality, this study used a combination of experimental and simulation methods to study the indoor particulate matter with a diameter of less than 2.5 µm (PM2.5) and carbon dioxide (CO2) concentrations under different operation conditions. The purification time and the PM2.5 concentration distribution under different conditions were compared with the condition in which the purifier was used alone. The results showed that the purification time required for the condition that the air conditioner runs together with the purifier was shortened by 15.2%. When the fresh air system is running together with the purifier, the purification time can be reduced by 30.4%. It was reduced by 32.6% when the three systems were operating at the same time. The PM2.5 concentration distribution under the joint operating condition was much more even than that under the condition in which the purifier was running alone. To analyze the impact on the CO2 distribution, the CO2 distributions under different joint operations were compared. The results show that the fresh air system can effectively dilute CO2 below 1000 ppm in 30 min. The air conditioner and purifier could help to mix the indoor air to provide a much more uniform indoor CO2 distribution. [ABSTRACT FROM AUTHOR]

A living wall, when integrated with a mechanical ventilation system, can effectively improve the indoor thermal environment and reduce indoor CO2 concentration during the transition season. In this study, a control experiment was conducted to analyze the effect of a living wall integrated with mechanical ventilation (LW-V) on indoor air quality. During the experiment, indoor air temperature, relative humidity, indoor air speed, and CO2 concentration were measured, while the skin temperature was monitored and subjective questionnaires were administered to 60 subjects. The results show that the indoor environment was effectively improved by employing the LW-V system, with the average indoor temperature decreasing by 1.45 °C, while relative humidity increased by 19.1%. Due to the plant photosynthesis, CO2 concentrations were reduced by 13.83 ppm. Meanwhile, the mean skin temperature was reduced by 0.18 °C and was closer to the neutral mean skin temperature. Questionnaire analysis reveals the LW-V system improved overall air freshness sensation and thermal comfort level by 1.09 and 0.53, respectively. The LW-V system improved the indoor thermal environment as well as air quality during the transition season significantly. [ABSTRACT FROM AUTHOR]

Plant productivity is enhanced by elevated atmospheric CO2 concentration, but N content of leaf is reduced. How atmospheric CO2 affects leaf 15N composition and the related mechanisms remain unclear. δ15N and N content of wheat and sunflower leaves were determined under two CO2 concentration(410 and 820 μmol·mol-1) treatments. The results show that the N content of both species decreases with elevated CO2 concentration, but the response of δ15N to CO2 enrichment is different between wheat and sunflower. Under high CO2 concentration treatment, δ15N of wheat leaves decreases significantly by 6.5‰, while δ15N of sunflower leaves increases slightly by 2.1‰, accompanied by a significant increase in leaf mass and aboveground biomass. Therefore, N nutrition characteristics of wheat are consistent with N assimilation limitation hypothesis, while the response of sunflower is consistent with dilution effect hypothesis. δ15N in wheat leaves decreases significantly with leaf aging and cell aging. Therefore, when using δ15N to infer environmental impacts on plant N metabolism, it is necessary to account for the leaf age effect. The results of meta-analysis show that δ15N of non-legume C3 plants decreases significantly by 0.3‰ under elevated CO2 concentration, in line with our results on wheat plants. The study shows that the inhibited N assimilation is an important mechanism related to the CO2 effect on N metabolism and 15N content of plants [ABSTRACT FROM AUTHOR]

To explore the effects of different CO2 concentrations and nitrogen fertilizer levels on the respiration rate of paddy fields, a field experiment was conducted using 12 open-top chambers. Three levels of CO2 concentration were set: the control(CK, ambient atmospheric CO2 concentration), and CO2 concentrations increased by 120 μmol·mol-1 (C1)and 200 μmol·mol-1 (C2)compared with CK. Nitrogen fertilizer was set at two levels: low nitrogen application(N1, 15 g·m-2 )and conventional nitrogen fertilizer(N2, 25 g·m-2 ), with a total of 6 treatments in the experiment. The results showed that under the same nitrogen application level, the respiration rate of the C1N1 treatment decreased by 23.4%(P=0.045)and 49.1%(P=0.010)compared with the CKN1 treatment at the filling stage and wax ripening stage, respectively. During the heading and grain-filling stages, the respiration rates of the C2N2 treatment increased by 12.3%(P=0.009)and 16.8%(P=0.047)compared with the CKN2 treatment, respectively. Under the same level of CO2 concentration, the respiration rates of different nitrogen application levels showed that N2>N1 and showed a significant level during the elongation and heading stages and an extremely significant level during the grain filling stage. In the grain filling and wax ripening stages, the respiration rates of C1N1 treatment decreased by 31.1%(P=0.004)and 42.7%(P=0.010), respectively, compared with C1N2 treatment. This paper demonstrates that the effect of elevated atmospheric CO2 concentration on the respiration rate of paddy fields varies with the growth period, and nitrogen fertilizer reduction can reduce the respiration rate and CO2 accumulation in paddy fields. [ABSTRACT FROM AUTHOR]

In Poland and other countries in Central Europe, residential buildings from the second half of the 20th century dominate, which have recently undergone deep thermomodernisation. Research on the retrofitting of residential buildings has focused mainly on energy efficiency, with only a few studies on indoor air quality. The aim of this study was to present a comparative analysis of the impact of five ventilation scenarios (three natural and two mechanical) on CO2 concentration and energy demand for heating and ventilation in residential spaces of a multi-family building located in Poland. The analyses were based on the results of building performance co-simulation using the EnergyPlus and CONTAM programs carried out under dynamic conditions with a 5 min time step for the entire heating season. The calculations took into account the instantaneous occupancy variability of twenty apartments. In the buildings equipped with new tight windows, the natural ventilation system provided extremely low air exchange (on average 0.1 h−1) and poor indoor air quality (average CO2 concentration at the level of 2500 ppm). Opening windows to ventilate the rooms generated a multiple increase (up to 8 times) in heating demand during these periods, but average CO2 concentration was on the level of 930 ppm. The use of mechanical ventilation was profitable both in terms of energy savings (at the level of 50%) and improvement in the indoor air. [ABSTRACT FROM AUTHOR]

Current developments in vehicles have generated great interest in the research and optimization of heating, ventilation, and air conditioning (HVAC) systems as a factor to reduce fuel consumption. One of the key trends for finding solutions is the intensive development of electric transport and, consequently, additional requirements for reducing energy consumption and modifying climate systems. Of particular interest is the optimal functioning of comfort and life support systems during air recirculation, i.e., when there is a complete or partial absence of outside air supply, in particular to reduce energy consumption or when the environment is polluted. This work examines numerical models of airfields (temperature, speed, and humidity) and also focuses on the concentration of carbon dioxide and oxygen in the cabin, which is a critical factor for ensuring the health of the driver and passengers. To build a mathematical model, the Navier–Stokes equations with energy, continuity, and diffusion equations are used to simulate the diffusion of gases and air humidity. In the Ansys Fluent finite volume analysis package, the model is solved numerically using averaged RANS equations and k-ω turbulence models. The cabin of a mainline locomotive with two drivers, taking into account their breathing, is used as a transport model. The problem was solved in a nonstationary formulation for the design scenario of summer and winter, the time of stabilization of the fields was found, and graphs were constructed for different points in time. A comparative analysis of the uniformity of fields along the height of the cabin was carried out with different locations of deflectors, and optimal configurations were found. Energy efficiency values of the climate system operation in recirculation operating modes were obtained. A qualitative assessment of the driver's blowing directions under different circulation and recirculation modes is given from the point of view of the concentration of carbon dioxide in the breathing area. The proposed solution makes it possible to reduce electricity consumption from 3.1 kW to 0.6 kW and in winter mode from 11.6 kW to 3.9 kW and save up to 1.5 L/h of fuel. The conducted research can be used to develop modern energy-efficient and safe systems for providing comfortable climate conditions for drivers and passengers of various types of transport. [ABSTRACT FROM AUTHOR]

The first experimental results of the indoor air quality in two kindergartens located in the Republic of Srpska are presented in this paper. Kindergarten representatives for the year of construction (old and new), building materials, and energy efficiency have been chosen. Indoor air quality measurements (air temperature, relative humidity, ventilation rate, CO2, and radon concentration) were performed during the winter of 2015/2016. Measured indoor air quality parameters are discussed and compared to the international standards BAS EN 16798-1, ASHRAE 62.1, and ISO 7730. The average measured radon concentrations for both buildings have not exceeded the level of 200 Bq/m³, but for reliable results, long-term measurement needs to be performed. The CO2 concentration in the old kindergarten fulfills the BAS EN 16798-1 requirement for Category I during 62.43% of total occupancy time, while for the new kindergarten, it is only 5.79% of full occupancy time. Results of CO2 concentration confirm that good sealing of the envelope of new buildings and user behavior (number of users and natural ventilation) does affect air quality. Furthermore, a high correlation between CO2 concentration and relative humidity in both buildings and a more considerable correlation for the new building have been observed. [ABSTRACT FROM AUTHOR]

As constituents of one of the vital agricultural ecosystems, paddy fields exert significant influence on the global carbon cycle. Therefore, conducting observations and simulations of CO2 flux in rice paddy is of significant importance for gaining deeper insights into the functionality of agricultural ecosystems. This study utilized an eddy covariance system to observe and analyze the CO2 flux in a rice paddy field in Eastern China and also introduced and parameterized the Jarvis multiplicative model to predict the CO2 flux. Results indicate that throughout the observation period, the range of CO2 flux in the paddy field was −0.1 to −38.4 μmol/(m2·s), with a mean of −12.9 μmol/(m2·s). The highest CO2 flux occurred during the rice flowering period with peak photosynthetic activity and maximum CO2 absorption. Diurnal variation in CO2 flux exhibited a "U"-shaped curve, with flux reaching its peak absorption at 11:30. The CO2 flux was notably higher in the morning than in the afternoon. The nocturnal CO2 flux remained relatively stable, primarily originating from respiratory CO2 emissions. The rice canopy CO2 flux model was revised using boundary line analysis, elucidating that photosynthetically active radiation, temperature, vapor pressure deficit, phenological stage, time, and concentration are pivotal factors influencing CO2 flux. The simulation of CO2 flux using the parameterized model, compared with measured values, reveals the efficacy of the established parameter model in simulating rice CO2 flux. This study holds significant importance in comprehending the carbon cycling process within paddy ecosystems, furnishing scientific grounds for future climate change and environmental management endeavors. [ABSTRACT FROM AUTHOR]

The urgency of addressing climate change has necessitated innovative and practical approaches to reducing greenhouse gas emissions. Cryogenic Carbon Capture (CCC) technology has emerged as a promising solution for capturing CO2 from industrial emissions. This study investigates a simplified design for a precooling system within CCC technology, focusing on optimizing the efficiency and reliability of the system while minimizing energy consumption. The research examines the effects of CO2 concentration in a gas mixture (simulated flue gas, nitrogen and carbon dioxide), cooling bath temperature, and gas mixture flow rate on the performance of heat exchangers in the precooling system. Theoretical, numerical, and experimental analyses were conducted to assess the system's performance. The use of liquid nitrogen at −196 °C in the cooling bath was found unsuitable due to CO2 freezing within the pipes. Instead, a mixture of dry ice and isopropyl alcohol at −78.5 °C proved effective in maintaining consistent temperature and pressure conditions without causing CO2 blockages. Numerical simulations highlighted the importance of optimizing pipe length to balance temperature control and pressure dynamics, with a 140 cm pipe length identified as optimal for heat exchanger design. Experimental results revealed that longer pipes enhance cooling performance due to increased heat exchange surface area, while higher CO2 compositions and flow rates result in higher outlet temperatures and pressures. The study emphasizes the need for further research and simulation work to refine heat exchanger designs for industrial applications, aiming to develop systems that maximize cooling efficiency while ensuring reliable operation.

Field experiment was conducted at Punjab Agricultural University, Bathinda from 2017-18 to 2019-20 to evaluate the growth and yield of wheat under varying sowing dates (Nov. 15, Nov. 30 & Dec 15), irrigation regimes (IW: CP = 0.6, 0.8, & 1.0), and nitrogen levels 80% RDN, RDN & 120% RDN). Timely sowing (15 November) resulted in significantly highest grain yield (5090 kg ha-1) and delay in sowing caused reduction in yield by 2.83 % and 9.91 % in crop sown on 30 November and 15 December respectively. Yield and yield attributes were found to increase with increase in irrigation and nitrogen levels. The highest yield was achieved with 15 November sowing, IW: CPE ratio 1.0 and 120% RDN. The sensitivity of the validated CERES-wheat model to increase in temperature by 0.7, 1.2, 1.5 0C and CO2 concentration by 435, 460, 500 ppm, as projected for years 2030, 2040 and 2050 respectively, revealed reduction in the wheat yield. The combination of 15 November sown crop, irrigation at IW:CPE ratio 1.0, and recommended dose of nitrogen showed resilience against increasing CO2 concentration and temperature rise.

Ecosystem water use efficiency (WUE) is a key indicator for understanding the response of carbon–water processes to environmental changes. However, as affected by uncertainty of WUE estimation and attribution, the individual contributions of environmental drivers to WUE changes and the underlying mechanisms remain unclear on the Tibetan Plateau (TP). Here, a theory-based analytical WUE model was modified by introducing an optimal stomatal behavior model, and used to estimate monthly WUE and their drivers during 1982–2018 for main vegetation types on the Tibetan Plateau (TP). Rationality of three mainstream analytical attribution methods—analytical-based partial derivative method (APDM), regression-based partial derivative method (NPDM), and climate elasticity method (CEM)—was examined. Furtherly, the contributions of various environmental drivers to WUE variation trend were estimated for various vegetation types. Results indicate that: (1) The modified model performed well in estimating WUE against with observed WUE at five eddy-covariance (EC) flux stations, which decreased the uncertainty of WUE estimation. WUE increased significantly in the TP with a slope of 0.49 × 10-2 g C kg−1 H2O yr−1 during 1982–2018 with forests increased most rapidly; (2) Only APDM captured both the variation and magnitude of WUE trends, and both NPDM and CEM failed to reproduce the magnitude of WUE trends, though CEM was better than NPDM benefited from its nonlinear structure. Through comparing these methods, we found that the nonlinear direct effects of these forcing variables on WUE change could be higher than their indirect effects caused by their interactions. (3) There are some differences in the main drivers of WUE trends for various vegetation types. Increase in WUE was mainly driven by the increase in leaf area index (LAI) for both steppes and meadows, while decreased air water vapor pressure deficit (VPD) and elevated CO2 showed higher positive effects for broad-leaf forests. The distinct response and extremely scarce EC observations of forests suggest that more attention should be paid to forests in the TP. This study could help in selection of attribution methods and understanding the mechanisms of carbon–water coupling of alpine ecosystems under a changing climate.

CO2 has rarely been examined as a fire indicator owing to the uncertainty in its background concentration. Nevertheless, for a specific building space with a detector, the background CO2 concentration signal can be determined and documented using artificial intelligence technology. Based on the aforementioned concept, this study explored the feasibility of using CO2 signal features as fire indicators for building fire detection. First, CO2 concentrations under fire and no-fire conditions were obtained to generate study databases. Second, the deep temporal clustering (DTC) model was used to classify CO2 signal features between fire and no-fire scenes, and the clustering accuracy and purity were selected to determine the clustering performance. Third, the k-means, agglomerative clustering, and spectral bi-clustering models were employed to validate the clustering advantages of the DTC model. The results proved the CO2 concentration to be more suitable as a combustion indicator for fire detection compared to the CO2 concentration rate, exhibiting higher clustering accuracy and purity values. Additionally, for time-series clustering, the DTC model outperformed traditional clustering models. The findings of this study represent a fundamental step toward the realization of space-exclusive multi-sensor fire-detection technology for assisting smart building construction in a cost-effective and accurate manner.

Climate change, characterized by rising atmospheric CO2 levels and temperatures, poses significant challenges to global crop production. Sweet sorghum, a prominent C4 cereal extensively grown in arid areas, emerges as a promising candidate for sustainable bioenergy production. This study investigated the responses of photosynthesis and leaf-scale water use efficiency (WUE) to varying light intensity (I) in sweet sorghum under different temperature and CO2 conditions. Comparative analyses were conducted between the An-I, gs-I, Tr-I, WUEi-I, and WUEinst-I models proposed by Ye et al. and the widely utilized the non-rectangular hyperbolic (NRH) model for fitting light response curves. The Ye's models effectively replicated the light response curves of sweet sorghum, accurately capturing the diminishing intrinsic WUE (WUEi) and instantaneous WUE (WUEinst) trends with increasing I. The fitted maximum values of An, gs, Tr, WUEi, and WUEinst and their saturation light intensities closely matched observations, unlike the NRH model. Despite the NRH model demonstrating high R2 values for An-I, gs-I, and Tr-I modelling, it returned the maximum values significantly deviating from observed values and failed to generate saturation light intensities. It also inadequately represented WUE responses to I, overestimating WUE. Across different leaf temperatures, An, gs, and Tr of sweet sorghum displayed comparable light response patterns. Elevated temperatures increased maximum An, gs, and Tr but consistently declined maximum WUEi and WUEinst. However, WUEinst declined more sharply due to the disproportionate transpiration increase over carbon assimilation. Critically, sweet sorghum An saturated at current atmospheric CO2 levels, with no significant gains under 550 mmol mol-1. Instead, stomatal closure enhanced WUE under elevated CO2 by coordinated gs and Tr reductions rather than improved carbon assimilation. Nonetheless, this response diminished under simultaneously high temperature, suggesting intricate interplay between CO2 and temperature in modulating plant responses. These findings provide valuable insights into photosynthetic dynamics of sweet sorghum, aiding predictions of yield and optimization of cultivation practices. Moreover, our methodology serves as a valuable reference for evaluating leaf photosynthesis and WUE dynamics in diverse plant species. [ABSTRACT FROM AUTHOR]

The phenology has gained considerably more attention in recent times of climate change. The transition from vegetative to reproductive phases is a critical process in the life history of plants, closely tied to phenology. In an era of climate change, understanding how environmental factors affect this transition is of paramount importance. This study consisted of field surveys and a greenhouse experiment on the reproductive biology of Northern pipevine (Aristolochia contorta Bunge). During field surveys, we investigated the environmental factors and growth characteristics of mature A. contorta, with a focus on both its vegetative and reproductive phases. In its successful flowering during the reproductive phase, A. contorta grew under the conditions of 40% relative light intensity and 24% soil moisture content, and had a vertical rhizome. In the greenhouse experiments, we examined the impact of increased CO2 concentration on the growth and development of 10-year-old A. contorta, considering the effect of rhizome direction. Planted with a vertical rhizome direction, A. contorta exhibited sufficient growth for flowering under ambient CO2 concentrations. In contrast, when planted with a horizontal rhizome direction, it was noted to significantly impede successful growth and flowering under elevated CO2 concentrations. This hindered the process of flowering, highlighting the pivotal role of substantial vegetative growth in achieving successful flowering. Furthermore, we observed a higher number of underground buds and shoots under the conditions of elevated CO2 concentration and a horizontal rhizome direction instead of flowering. Elevated CO2 concentrations also exhibited diverse effects on mature A. contorta's flower traits, resulting in smaller flower size, shorter longevity, and reduced stigma receptivity, and pollen viability. The study shed light on elevated CO2 concentrations can hinder growth, potentially obstructing sexual reproduction and diminishing genetic diversity. [ABSTRACT FROM AUTHOR]

Shared public buildings have become centers of innovation, integrating advanced technologies to meet evolving societal needs. With a heightened emphasis on occupants' health and well-being, these buildings serve as hubs for technological convergence, facilitating seamless connectivity and intelligent data analysis and management. Within this context, environmental monitoring emerges as a foundational element, pivotal to all aspects of building management. This article provides findings from the nationally funded RE-START project, which focuses on shared public buildings, with special regard to educational and medical facilities. The project explores enhanced indoor air quality monitoring, focusing on CO2 concentration that is directly correlated with occupancy, as a fundamental element for developing health and safety protocols, energy efficiency strategies, the integration of smart building technologies, and data-driven energy management. The intersection of environmental monitoring, energy efficiency, security, and IoT technologies in in indoor spaces is relevant. The outcomes of the study reveal the delicate nature of all the involved components, which need to be carefully developed in an integrated manner. [ABSTRACT FROM AUTHOR]

It is commonly recognized that the observed increase in global mean annual air temperature is strongly related to the increase in global carbon dioxide concentration C, and that both these variables are related to global development. It remains, however, unclear the degree to which local mean annual urban air temperature T is affected by local variables such as annual precipitation depth P and urban area extent A. This study assumes that A is a proxy of local development and C is a proxy of global development and investigates the commingled effects of A, P, and C on T by using long-term annual data observed over the years 1881–2019 from the Modena Observatory in Italy. Linear relationships between T, C and A are found to be spurious since all these series have a monotonic increasing trend with time. Parametric analytic models like logistic functions are found to lack flexibility. Smoothing splines can only give insights into the strength of the relationships but not on their shape defining the functional relationship between variables. Advanced nonlinear models like generalized additive models, instead, are found to combine flexibility in a parametric form, and appear therefore to be suitable models for explaining the complex relationships between A, P, and C on T. The different models are evaluated using traditional goodness of fit statistics like R2, AIC, BIC, and a new index of relation IR which is introduced to jointly evaluate the goodness-of-fit of relationships between variables that may either be dependent or independent. [ABSTRACT FROM AUTHOR]

The present study to quantify the variations in microclimate under wheat, mustard and chickpea crops was conducted at ICAR-Indian Institute of Farming Systems Research, Modipuram, Meerut (U.P.), India. Air temperature, relative humidity and CO2 concentration below and above the canopies of wheat, mustard and chickpea were recorded at hourly interval from 07:30 to 17:30 hours at different heights (0.5 m, 1.0 m and 2.0 m) from the ground. CO2 probes like GMP-343, (Diffusion aspiration) was used to record data of CO2 concentration and HPM-75 probes was used to capture the observation of air temperature and relative humidity. Results revealed that diurnal air temperature was continuously increasing from morning to afternoon hrs and highest air temperature was recorded at 13:30 hrs (afternoon). Thereafter, air temperature decreased and reached to the lowest at 17:30 hrs irrespective of crops and height from the ground. Analysis of diurnal air temperature variations at different height clearly showed that tall statured crop such as wheat and mustard reached higher air temperature regime early (13.30 hrs) compared to short statured crop like chickpea at 15.30 hrs. Highest relative humidity was observed at 07.30 hrs and lowest relative humidity was recorded either at 13:30 hrs or at 15:30 hrs. As per study maximum CO2 concentration was found at 07:30 hrs morning and minimum at 15:30 hrs. The lowest concentration of CO2 (624 ppm) was recorded from the chickpea field and highest from the mustard field (630 ppm) at the same point of observation during vegetative phase of crops. [ABSTRACT FROM AUTHOR]

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Microclimate modelling in a greenhouse is complicated due to the model's irregularity and uncertainty of variable parameters. Evaluating the greenhouse's changing climate is challenging since the conditions are always changing. As a result, it is necessary to determine the best way to manage the microclimate for the healthy development of growing plants. In order to maximise the growth of blooming plants, a modified leader optimisation algorithm (MLA) is created in this study to control the inside environment of a greenhouse. The implementation is done using greenhouses with a double-span structure located in Punjab and Mohali in India. The recommended approach analyses a number of characteristics, including carbon dioxide (CO2) concentration, temperature, and humidity, to keep track of the greenhouse's environment. The humidity, temperature and CO2 content of flowering plants are studied using the proposed method implemented using MATLAB tool. The evaluated parameters are compared to conventional techniques like Battle Royale Optimisation (BRO), Particle Swarm Optimisation Algorithm (PSO), and BAT algorithm (BAT). Cost and energy consumption are also calculated for both proposed and existing models. Additionally, for the microclimatic parameters, error metrics, including Mean Absolute Error (MAE), Maximum Absolute Error (MaxAE), Mean Square Error (MSE), Root Mean Square Error (RMSE), and Standard Deviation (STD) are analysed and compared with the conventional approaches. The comparative outcomes highlight the minimal error metrics of a suggested MLA for temperature, humidity, and CO2 levels in blooming plants. The result analysis proves that the proposed MLA model is better than the previous models for predicting the proper range of CO2 concentration, suitable temperature, and perfect humidity for flowering plants. This demonstrates the effectiveness of the proposed MLA approach compared to the established methods for developing blooming plants. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Health problems and respiratory diseases are associated with poor indoor air ventilation. We investigated the air quality inside a classroom-laboratory where no ventilation is provided. The case of study, consisting of an internal enclosure, is located at the Escuela Técnica Superior de Edificación (ETSEM) of Madrid (Spain). The high height favours air stratification which is analysed in terms of temperature and CO2 spatial distribution. Temperature, air humidity, atmospheric pressure and CO2 concentration measurements were taken in time at three different height locations. A CFD numerical model was established to analyse air quality. Flow circulation is derived by solving full 3D Navier – Stokes governing equations, coupled with the thermal problem. The diffusion problem of the CO2 produced by the inner occupants is then derived from the kinematics solution. Three scenarios were taken into account: occupants seated (1), standing (2), half seated, half standing (3). Results clearly show the air stratification as a result of density gradient, which is in turn determined by temperature difference between the occupants and the surrounding air. Temperature prediction maximum relative error is contained to 3.5 %. As expected, CO2 concentration increases over time, reaching maximum values depending on the configuration considered and height location.

The article focuses on an analysis of the indoor climate in a small, newly-built auditorium. Providing optimal indoor climate parameters in the interiors of a university is extremely important for students. Meeting these parameters is essential not only from a physiological point of view, but also to achieve desirable student performances. The parameters of CO2 concentration are also influenced by the air distribution system in a small auditorium. The correct positions of the supply and extract air is very important. The first experimental measurements of CO2 concentration were carried out in a small auditorium in an old building. The natural ventilation of the small auditorium was evaluated. The second experimental measurements of the CO2 concentration were made in a small auditorium in a newly-built building. The ventilation system and the modern air distribution system of the small, newly-built auditorium were evaluated based on the CO2 concentration and the PMV index. A Testo 480 was used for the measurements. The conclusion of this paper contains the recommendations for the design of a newly-built ventilation system in a small auditorium.

Nitrogen (N) resorption is an important pathway of N conservation, contributing to an important proportion of plant N requirement. However, whether the ratio of N resorption to N requirement may be affected by environmental factors, mycorrhizal types or atmospheric CO2 concentration remains unclear. Here, we conducted a meta‐analysis on the impacts of environmental factors and mycorrhizal types on this ratio. We found this ratio in ectomycorrhizal (EM) trees decreased with mean annual precipitation, mean annual temperature, soil total N content and atmospheric CO2 concentration and was significantly lower than that in arbuscular mycorrhizal (AM) trees. An in situ15N tracing experiment further confirmed that AM trees have a stronger reliance on N resorption than EM trees. Our study suggests that AM and EM trees potentially have different strategies for alleviation of progressive N limitation, highlighting the necessity of incorporating plant mycorrhizal types into Earth System Models. [ABSTRACT FROM AUTHOR]

In the northern high latitudes, warmer spring temperatures generally lead to earlier leaf onsets, higher vegetation production, and enhanced spring carbon uptake. Yet, whether this positive linkage has diminished under climate change remains debated. Here, we used atmospheric CO2 measurements at Barrow (Alaska) during 1979–2020 to investigate the strength of temperature dependence of spring carbon uptake reflected by two indicators, spring zero‐crossing date (SZC) and CO2 drawdown (SCC). We found a fall and rise in the interannual correlation of temperature with SZC and SCC (RSZC‐T and RSCC‐T), showing a recent reversal of the previously reported weakening trend of RSZC‐T and RSCC‐T. We used a terrestrial biosphere model coupled with an atmospheric transport model to reproduce this fall and rise phenomenon and conducted factorial simulations to explore its potential causes. We found that a strong–weak–strong spatial synchrony of spring temperature anomalies per se has contributed to the fall and rise trend in RSZC‐T and RSCC‐T, despite an overall unbroken temperature control on net ecosystem CO2 fluxes at local scale. Our results provide an alternative explanation for the apparent drop of RSZC‐T and RSCC‐T during the late 1990s and 2000s, and suggest a continued positive linkage between spring carbon uptake and temperature during the past four decades. We thus caution the interpretation of apparent climate sensitivities of carbon cycle retrieved from spatially aggregated signals. [ABSTRACT FROM AUTHOR]

To address the problem that there are many limestone particle decomposition reaction models and it is difficult to accurately select the appropriate one, this paper established two typical one-dimensional unsteady numerical calculation models for single-particle limestone decomposition, coupling the convective heat transfer, thermal conduction, and CO2 mass transfer processes. Two numerical calculation models were solved through the Matlab R2021a platform, and the internal temperature, CO2 concentration distribution, and decomposition reaction rate of the limestone particles during the period from the beginning of temperature rise to the end of decomposition were obtained. Compared with the experimental data, Model 1 has a better agreement with a relative error of less than 10%. The simulation results have shown that the average decomposition reaction rate is 20% higher than the average mass transfer rate. As the particle size increases from 20 mm to 80 mm, the time required for temperature rise in the initial stage changes from 6.6 min to 42.7 min. It is noted that the CO2 volume fraction increment increases by 0.42% with a particle size of 80 mm and a heating temperature of 1050 °C, indicating that the influence of the distribution of CO2 on the limestone decomposition may not be ignored. [ABSTRACT FROM AUTHOR]

Artificial lighting is complementary and single-source lighting for controlled Environment Agriculture (CEA) to increase crop productivity. Installations to control CO2 levels and luminaires with variable spectrum and intensity are becoming increasingly common. In order to see the net assimilation of CO2 based on the relationship between the three factors: intensity, spectrum and CO2 concentration, tests are proposed on tomatoes seedling with combinations of ten spectra (100B, 80B20G, 20B80G, 100G, 80G20R, 20G80R, 100R, 80R20B, 20R80B, 37R36G27B) seven light intensities (30, 90, 200, 350, 500, 700 and 1000 μmol·m-2 s-1) and nine CO2 concentrations (200, 300, 400, 500, 600, 700, 800 and 900 ppm). These tomato seedlings grew under uniform conditions with no treatments applied up to the moment of measurement by a differential gas analyzer. We have developed a model to evaluate and determine under what spectrum and intensity of light photosynthesis the Net assimilation of CO2 (An) is more significant in the leaves of tomato plants, considering the CO2 concentration as an independent variable in the model. The evaluation of the model parameters for each spectrum and intensity shows that the intensity has a more decisive influence on the maximum An rate than the spectra. For intensities lower than 350 μmol·m-2 s-1, it is observed that the spectrum has a greater influence on the variable An. The spectra with the best behaviour were 80R20B and 80B20R, which maintained An values between 2 and 4 (μmol CO2·m-2·s-1) above the spectra with the worst behaviour (100G, 80G20R, 20G80R and 37B36G27R) in practically all situations. Photosynthetic Light-Use Efficiency (PLUE) was also higher for the 80B20R and 20R80B spectra with values of 36,07 and 33,84 mmol CO2·mol photon-1, respectively, for light intensities of 200 μmol·m-2 s-1 and 400 ppm of CO2that increased to values of 49,65 and 48,38 mmol CO2·mol photon-1 for the same light intensity and concentrations of 850 ppm. The choice of spectrum is essential, as indicated by the data from this study, to optimize the photosynthesis of the plant species grown in the plant factory where light intensities are adjusted for greater profitability. [ABSTRACT FROM AUTHOR]

The increasing CO2 concentration ([CO2]) in the atmosphere decreases mineral nutrients concentration in crops, whereas it increases water use efficiency (WUE). Partial root-zone irrigation (PRI) could not only increase WUE but also improve plant nutrient status. Yet the effect of PRI combined with elevated CO2 concentration (e[CO2]) on the element stoichiometry of tomato leaves remains unknown. This study sought to investigate the responses of leaf mineral nutrients status and element stoichiometric ratios in tomatoes to PRI combined with e[CO2]. Tomato plants (cv. Ailsa Craig) were grown in pots in climate-controlled growth chambers with ambient [CO2] (a[CO2], 400ppm) and elevated [CO2] (e[CO2], 800ppm), respectively. Three irrigation regimes, i.e., full irrigation (FI), deficit irrigation (DI) and PRI, were applied to tomato plants at the flowering stage. The results showed that plants grown under DI and PRI had a similar biomass, enhanced root growth including greater root to shoot ratio, root length, surface area, volume and specific length, and an improved WUE in comparison with FI under e[CO2]. Additionally, under e[CO2], PRI showed an increase in leaf [C](+1.5%) and [N] (+9.3%), no decrease in leaf [K], [Ca], [Mg], [S] and [15N], but a decrease in leaf C/N (−6.6%) as compared with FI. Conclusively, PRI had the ability to improve leaf N concentration, maintain most leaf mineral nutrient concentrations, and optimize or maintain leaf element stoichiometric ratios under e[CO2]. Therefore, PRI would be a practicable mode of irrigation for optimizing WUE and nutrient status in tomato leaves in a future freshwater-limited and higher-CO2 environment. [ABSTRACT FROM AUTHOR]

The crystal blockage of the tunnel drainage system seriously affects the safety and stability of the lining structure of the tunnel, and there are many factors that affect the crystal blockage of the system. CO2 concentration is one of the factors. This paper uses indoor model test to study the influence of CO2 concentration on the crystallization of tunnel drainage pipe under different water filling conditions is studied. First, it studies the crystallization amount of each pipe section under six working conditions. According to the results, the crystallization amounts of sections 4 and 5 of the pipe are greater than those of other sections. Section 5 has the highest amount of crystallization. In other words, the crystallization happens more at the outlet section of the horizontal drainage pipe; (2) When the CO2 concentration between 10~15 kg/cm², the crystallization amount of the test pipe gets an upward trend and when the CO2 concentration is around 15 kg/cm², the crystallization reaches its maximum; (3) When the test tube is filled with water, the amount of crystallization will decrease as the flow rate becomes higher. When the factor of CO2 concentrations is controlled, the crystallization amount is less when all the pipe is filled with water than when it is half filled. The research results can guide the maintenance and daily monitoring of the tunnel drainage system, and support the formulation of the daily maintenance plan for the drainage system. [ABSTRACT FROM AUTHOR]

Due to the low melt strength, PET foam cells easily grow, and due to the low CO2 concentration in PET, generating more nucleation sites during the foaming process is difficult. As a result, PET foam produced using the supercritical CO2 foaming method possesses a large cell size and a low expansion ratio, which leads to poor mechanical performance. In addition, there has not been much research on how to improve CO2 concentration in PET. In this work, the PC with higher melt strength and CO2 absorption capacity was incorporated into the PET matrix to improve the foaming behaviors of the blend. The results showed that the melt strength and CO2 concentration of PET/PC blends are much higher than that of pure PET. For instance, the melt strength and CO2 concentration of the PET/PC10 blend would be more than twice that of pure PET when the PC content is only 10%wt. By studying the foaming behavior, it was found that high melt strength inhibited the cell overgrowth and collapse of PET/PC foam, resulting in the foam with good cell structure was obtained. In addition, the high CO2 concentration in PET/PC blend is conducive to cell nucleation, thereby increasing the foam expansion ratio during the CO2 foaming process. Finally, the PET/PC blend foam with excellent mechanical properties was obtained. To be specific, the expansion ratio of the PET/PC blend foam was about 9.61, and the average cell size was only 40.38 µm. And the PET/PC blend foam possessed an excellent compressive strength of 7.41 MPa due to the strong interfacial bead cohesion, which showed the application prospect in the field of construction engineering. [ABSTRACT FROM AUTHOR]

To examine the effects of gradual increase of atmospheric CO2 concentration on soil respiration of winter wheat (Triticum aestivum) field, a gradually increased CO2 concentration experiment was conducted with automatic control system of CO2 in open top chambers (OTCs) during 2017-2019 growing seasons. In this study, a gradual increase of atmospheric CO2 concentration(C80 and C120,an increase of 40 μmol·mol-1 year by year from 2016) was set up based on the ambient atmospheric CO2 concentration (CK). The soil respiration rate (Rs) was measured by static chamber-gas chromatograph method. The results showed that gradually increased CO2 did not alter the seasonal patterns of soil respiration, but had significant effect on Rs during winter wheat bloom-growth period. In 2018-2019 growing season, compared to CK,C120 treatment significantly increased Rs by 50. 2% (P=0. 008) at the heading-flowering stage, and significantly increased cumulative amount of CO2 emissions (CAC) by 25. 9% (P=0. 044) during the wheat growing season; while in 2017-2018 growing season, compared to CK,C80 treatment had no significant effect on Rs. A positive exponential relationship was found between soil respiration rate and soil temperature. Compared to CK,gradually increased CO2 concentration reduced the temperature sensitivity coefficient of soil respiration (Q10 values). In summary, a gradual increase of atmospheric CO2 concentration of 120 μmol·mol-1 increased CAC during the growing season of winter wheat. [ABSTRACT FROM AUTHOR]

A person spends about a third of their life sleeping, and high sleep quality is very important for health. Environmental factors are one of the most important factors affecting sleep quality, and indoor carbon dioxide (CO2) concentration while sleeping has a significant effect on sleep quality. In an indoor bedroom with no open windows and no fresh air system, different numbers of people sleeping will lead to changes in indoor CO2 concentration. In order to study the changes in sleep quality caused by differences in CO2 concentration, experimental research was performed. Objective sleep quality data are collected with polysomnography (PSG) and a subjective questionnaire. The sleep quality of the subjects is tested under three different CO2 concentration levels; the average carbon dioxide concentration of three conditions is 680, 920, and 1350 ppm, which simulate a room with 1, 2, and 3 people sleeping, respectively. Other environment parameters are controlled as follows: test environment temperature is 26 ± 0.5 °C, relative humidity is 50 ± 5%, there is no obvious heat source in the test room, and the radiation temperature and air temperature difference is less than 1 °C. A total of 30 subjective tests were carried out with 10 subjects; the test lasted more than one month. The data subsequently underwent statistical analysis to determine the influence of CO2 concentration on sleep quality. The results show that as the CO2 concentration level increased, the sleep quietness and satisfaction of the subjects gradually decreased, the sleep duration gradually decreased, and symptoms such as throat discomfort, dyspnea, dry and itchy skin, difficulty falling asleep, difficulty waking up, congested nose and bad air smell become more obvious. The PSG test results showed that CO2 concentration has a significant impact on the proportion of the N3 period. According to the group of CO2 concentration conditions, the mean of the N3 period proportion under the conditions of one person, two persons, and three persons is 20.4%, 17.3%, and 14.4%, respectively. Finally, there was also an increase in turning over or awakening during sleep, indicating that sleep quality was reduced under higher CO2 concentrations. [ABSTRACT FROM AUTHOR]

In this study, we analyze the performance of ventilation modules to improve air quality in educational facilities. Using (CFD), we examine the flow design variables of a window-mounted ventilation module. Using computational analysis, we analyze various flow design characteristics of window-mounted ventilation modules and review optimal conditions. First, we measure the carbon dioxide concentration in the classroom and use CFD to analyze the internal air characteristics according to the ventilation module's inflow speed, inflow angle, and indoor temperature conditions. According to classroom air quality management standards, the concentration of carbon dioxide must be managed below 1000 ppm. When the ventilation module's inflow velocity was 2.0 m/s, a carbon dioxide concentration of less than 1000 ppm was measured in the classroom. Additionally, an air filter was selected to prevent the inflow of external fine dust through the ventilation module. The suitability of HEPA H14 was reviewed to design the weight concentration of fine dust flowing from the ventilation module to be less than 50 μg/m3. Through research, flow design conditions for a window-mounted ventilation module were presented to reduce carbon dioxide concentration inside the classroom. The analysis of the ventilation system flow characteristics proposed in this study derived primary data for improving the classroom ventilation system. [ABSTRACT FROM AUTHOR]

The present study to quantify the variations in microclimate under wheat, mustard and chickpea crops was conducted at ICAR-Indian Institute of Farming Systems Research, Modipuram, Meerut (U.P.), India. Air temperature, relative humidity, CO2 concentration below and above the canopies of wheat, mustard and chickpea were recorded at hourly interval from 07:30 to 17:30 hours at different heights (0.5 m, 1.0 m and 2.0 m) from the ground. CO2 probes like GMP-343, (Diffusion aspiration) was used to record data of CO2 concentration and HPM-75 probes was used to capture the observation of air temperature and relative humidity. Results revealed that diurnal air temperature was continuously increasing from morning to afternoon hrs and highest air temperature was recorded at 13:30 hrs (afternoon). Thereafter, air temperature decreased and reached to the lowest at 17:30 hrs irrespective of crops and height from the ground. Analysis of diurnal air temperature variations at different height clearly showed that tall statured crop such as wheat and mustard reached higher air temperature regime early (13.30 hrs) compared to short statured crop like chickpea at 15.30 hrs. Highest relative humidity was observed at 07.30 hrs and lowest relative humidity was recorded either at 13:30 hrs or at 15:30 hrs. As per study maximum CO2 concentration was found at 07:30 hrs morning and minimum at 15:30 hrs. The lowest concentration of CO2 (624 ppm) was recorded from the chickpea field and highest from the mustard field (630 ppm) at the same point of observation during vegetative phase of crops.

Previous research in CO2 electroreduction primarily focused on cathodic electrocatalysts and electrode configurations using pure CO2. Few studies explored the impact of residence time and N2/O2 compounds, crucial for practical industrial implementation. In this study, the effect of residence time and the influence of N2 and O2 compounds on CO2 electroreduction to formate are investigated, employing Bi carbon-supported nanoparticles in the form of Gas Diffusion Electrodes within an electrochemical flow reactor with a single pass of the reactants. The results highlight the critical role of residence time and the impact of N2 and O2 compounds in the CO2 electroconversion process. On the one hand, the evaluation of residence time holds paramount significance for the potential establishment of a large-scale CO2 recycling plant, as it has the potential to significantly impact both the capital and operational costs of the integrated electrolyzer-separator system. Optimal results are obtained in the range of residence times between 1.8 and 2.9 seconds, corresponding to CO2 flow rates of 150 and 250 mL·min−1, respectively. On the other hand, the study resulted in a promising Faradaic Efficiency for formate of 75.0%, with similar values achieved at CO2 concentrations in the range of 75 – 100 vol%. These results are particularly noteworthy as they demonstrate that achieving a CO2 capture efficiency of 100% is not necessary, thereby reducing the costs associated with this process and, consequently, the overall cost of integrating both capture and utilization processes in a CO2 recycling plant.

The phenology has gained considerably more attention in recent times of climate change. The transition from vegetative to reproductive phases is a critical process in the life history of plants, closely tied to phenology. In an era of climate change, understanding how environmental factors affect this transition is of paramount importance. This study consisted of field surveys and a greenhouse experiment on the reproductive biology of Northern pipevine (Aristolochia contorta Bunge). During field surveys, we investigated the environmental factors and growth characteristics of mature A. contorta, with a focus on both its vegetative and reproductive phases. In its successful flowering during the reproductive phase, A. contorta grew under the conditions of 40% relative light intensity and 24% soil moisture content, and had a vertical rhizome. In the greenhouse experiments, we examined the impact of increased CO2 concentration on the growth and development of 10-year-old A. contorta, considering the effect of rhizome direction. Planted with a vertical rhizome direction, A. contorta exhibited sufficient growth for flowering under ambient CO2 concentrations. In contrast, when planted with a horizontal rhizome direction, it was noted to significantly impede successful growth and flowering under elevated CO2 concentrations. This hindered the process of flowering, highlighting the pivotal role of substantial vegetative growth in achieving successful flowering. Furthermore, we observed a higher number of underground buds and shoots under the conditions of elevated CO2 concentration and a horizontal rhizome direction instead of flowering. Elevated CO2 concentrations also exhibited diverse effects on mature A. contorta’s flower traits, resulting in smaller flower size, shorter longevity, and reduced stigma receptivity, and pollen viability. The study shed light on elevated CO2 concentrations can hinder growth, potentially obstructing sexual reproduction and diminishing genetic diversity.

The Federal District Integrated Recycling Complex (CIR-DF) contributes significantly to reducing the environmental impact of the waste produced by the metropolis of Brasilia, as it provides for the recycling of materials that would otherwise be taken to landfills and also employs around 450 collectors. That said, this work sought to monitor the air quality of the CIR/DF shed spaces, checking the concentration of CO2, temperature and humidity, in the period of intense heat and drought, relating the data with measures of adaptive comfort in order to contribute with space management. The results showed that the CO2 concentration is below 3,900 ppm in 48 hours per week indicated by NR 15. The temperatures verified between the six monitored days are, for the most part, below 50 % of the comfort zone and the humidity data are also below the 40 % limit indicated by NR 17. Thus, the Complex faces challenges related to the internal environmental comfort of the sheds, which can be improved by applying strategies for air renewal that are more appropriate to the location.

The aromatic odor of Plectranthus hadiensis var. tomentosus has been found to have the potential to improve physical and mental health of people in indoor environment, but its effectivess is reduced for that the release of volatile organic compounds from plants is susceptible to indoor environmental changes. The purpose of this study was to investigate the response of volatile organic compounds released by P. hadiensis var. tomentosus to common indoor environmental changes, and to provide a scientific basis for its efficient and sustainable application in building a comfortable pro-biotic environment to improve the physical and mental health of indoor personnel. Thus, the effects of four typical indoor environmental factors, such as air temperature, air relative humidity, CO2 concentration and light variation, on the release of volatile organic compounds from P. hadiensis var. tomentosus were investigated in this study. And the dynamic headspace and gas chromatography-mass spectrometry techniques were used to analyze the volatile organic compounds in different indoor environments with an environmental control device based on mixed-level orthogonal array design. The results were as follows: (1) Among the four typical indoor environmental factors of air temperature, air relative humidity, CO2 concentration and light condition, CO2 concentration and air temperature had greater effects on the release of volatile organic compounds from P. hadiensis var. tomentosus, while the effects of air relative humidity and light were weak. (2) For P. hadiensis var. tomentosus cultivated under normal photoperiod, an environmental condition with CO2 concentration of 500 μmol·mol-1, air temperature of 25℃ and air relative humidity of 60% was the most suitable for releasing volatile organic compounds from P. hadiensis var. tomentosus in the absence of light. Under this environmental condition, the total amount of volatile organic compounds released by P. hadiensis var. tomentosus was 86.23 μg·L-1·kg-1, and the content of biological active components with potentials for the positive intervention of physical and mental health was 78.03 μg·L-1·kg-1. In summary, the results suggest that when the aroma plant P. hadiensis var. tomentosus is used to build an indoor pro-biotic environment to maintain or improve the physical and mental health of people in indoor, the environmental conditions should be controlled properly, especially CO2 concentration and air temperature, so as to fully and efficiently produce the positive health benefits from P. hadiensis var. tomentosus.

This article focuses on the influence of occupants on the concentration of contaminants (radon Rn-222 and CO2) as well as the thermal comfort parameters. A series of sensors were placed to measure the concentration of the contaminants, temperature, and relative humidity in the test room at the Institute of Nuclear Physics PAN in Krakow (IFJ PAN), Poland. The test room is an office that is typical of the offices used in the facility. The occupants that used the space kept a detailed diary of their entry, exit, and number of people entering. The results showed that the accumulation of contaminants in such spaces may be severe and risks the health and safety of occupants. The accumulation of CO2 was extremely noticeable and did not diminish to the background level between the re-entry of the occupants to the office. The same was consistent for the radon concentration. The study shows how ventilation methods and small changes in occupant work strategy may influence the contaminant concentration within a test zone.

Various methodologies are used to estimate the impact of changing climatic factors, such as precipitation, temperature, and solar radiation, on crop production and water demand. In this study, the changes in rice yield, water demand, and crop phenology were estimated with varying CO2 concentration and an ensemble of general circulation models (GCMs), using a decision support system for agrotechnology transfer (DSSAT), a crop growth model. The measured CO2 concentration of 400 ppm from the Keeling curve, was used as the default CO2 concentration to estimate yield, water demand, and phenology. These outputs, obtained with the default concentration, were compared with the results from climate change scenarios’ concentrations. Further, the outputs corresponding to the ensembled GCMs’ climate data were obtained, and the results were compared with the ensembled crop model outputs simulated with each GCM. The yield was found to increase with the increase in CO2 concentration up to a certain threshold, whereas water demand and phenology were observed to decrease with the increase in CO2 concentration. The two approaches of the ensemble technique to obtain final outputs from DSSAT results did not show a large difference in the predictions.