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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.

Increasing CO2 concentration, temperature rise, and changes in rainfall due to climate change are expected to influence groundwater resources in irrigated agricultural regions. A simulation study using AquaCrop and MODFLOW models was undertaken to assess the combined effects of increasing CO2 concentrations, temperature, and rainfall changes on groundwater behavior in a rice–wheat cropping region of northwest India. Simulations were carried out for the 2016–2099 period under two scenarios: increasing CO2 concentrations corresponding to different RCPs (Scenario-I) and at a constant CO2 concentration of 369.4 ppm (Scenario-II). The results indicate that elevated CO2 negates the effect of rising temperature on evapotranspiration (ET) and water demand, and thus, lower ET is simulated under Scenario-I than Scenario-II for different RCPs during the future periods. The lower projected ET resulted in lower rice (2.3%–6.3%) and wheat (1.4%–16.1%) irrigation demand under Scenario-I than under Scenario-II. Of all RCPs, the lowest groundwater level (GWL) decline of 9.2, 20.5, and 24.4 m from the reference GWL (18.85 m) at the end of the early, mid-, and end-century periods, respectively, is projected under RCP8.5 and Scenario-I. Simulation results indicate that CO2 concentration plays an important role while assessing climate change effects on groundwater in irrigated agricultural systems. HIGHLIGHTS Quantified crop water budgeting components and their effect on groundwater levels in response to elevated CO2 concentration.; Rice irrigation requirement (IR) would decrease slightly while wheat IR significantly increased in future periods both in elevated CO2 and constant CO2 concentration scenarios.; Groundwater level is projected to decline less in elevated CO2 than in constant CO2 concentration scenario.;

Background: The Wells-Riley equation has been extensively used to quantify the infection risk of airborne transmission indoors. This equation is difficult to apply to actual conditions because it requires measurement of the outdoor air supply rate, which vary with time and are difficult to quantify. The method of determining the fraction of inhaled air that has been exhaled previously by someone in a building using a CO2 concentration measurement can solve the limitations of the existing method. Using this method, the indoor CO2 concentration threshold can be determined to keep the risk of infection below certain conditions. Methods: Based on the calculation of the rebreathed fraction, an appropriate mean indoor CO2 concentration and required air exchange rate to control SARS-CoV-2 airborne transmission was calculated. The number of indoor occupants, ventilation rate, and the deposition and inactivation rates of the virus-laden aerosols were considered. The application of the proposed indoor CO2 concentration-based infection rate control was investigated through case studies in school classrooms and restaurants. Results: In a typical school classroom environment with 20–25 occupants and an exposure time of 6–8 h, the average indoor CO2 concentration should be kept below 700 ppm to control the risk of airborne infection indoors. The ASHRAE recommended ventilation rate is sufficient when wearing a mask in classrooms. For a typical restaurant with 50–100 occupants and an exposure time of 2–3 h, the average indoor CO2 concentration should be kept below about 900 ppm. Residence time in the restaurant had a significant effect on the acceptable CO2 concentration. Conclusion: Given the conditions of the occupancy environment, it is possible to determine an indoor CO2 concentration threshold, and keeping the CO2 concentration lower than a certain threshold could help reduce the risk of COVID-19 infection.

Abstract Introduction Our aim was to gain insight into the effect of COVID-19 measures on SARS-CoV-2 incidence in secondary schools and the association with classroom CO2 concentration and airborne contamination. Methods Between October 2020—June 2021, 18 schools weekly reported SARS-CoV-2 incidence and completed surveys on school-initiated COVID-19 measures (e.g. improving hygiene or minimizing contacts). CO2 was measured in occupied classrooms twice, and SARS-CoV-2 air contamination longitudinally using electrostatic dust collectors (EDC) and analyzed using RT-qPCR. National COVID-19 policy measures varied during pre-lockdown, lockdown and post-lockdown periods. During the entire study, schools were recommended to improve ventilation. SARS-CoV-2 incidence rate ratios (IRR) were estimated by Generalized Estimating Equation (GEE) models. Results During 18 weeks follow-up (range: 10–22) SARS-CoV-2 school-incidence decreased during national lockdown (adjusted IRR: 0.41, 95%CI: 0.21–0.80) and post-lockdown (IRR: 0.60, 0.39–0.93) compared to pre-lockdown. School-initiated COVID-19 measures had no additional effect. Pre-lockdown, IRRs per 10% increase in time CO2 exceeded 400, 550 and 800 ppm above outdoor level respectively, were 1.08 (1.00–1.16), 1.10 (1.02–1.19), and 1.08 (0.95–1.22). Post-lockdown, CO2-concentrations were considerably lower and not associated with SARS-CoV-2 incidence. No SARS-CoV-2 RNA was detected in any of the EDC samples. Conclusion During a period with low SARS-CoV-2 population immunity and increased attention to ventilation, with CO2 levels most of the time below acceptable thresholds, only the national policy during and post-lockdown of reduced class-occupancy, stringent quarantine, and contact testing reduced SARS-CoV-2 incidence in Dutch secondary schools. Widespread SARS-CoV-2 air contamination could not be demonstrated in schools under the prevailing conditions during the study.

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.

In the face of global warming, the photosynthesis and transpiration of plants will change greatly, which will ultimately affect the water use efficiency (WUE) of plants. In order to study the coupling effects of CO2 and temperature on WUE of maize at ear stage, ‘Zhengdan 958’ was taken as the research object, and 5 temperatures (20 °C, 25 °C, 30 °C, 35 °C and 40 °C) and 11 CO2 concentration (400, 300, 200, 150, 100, 50, 400, 400, 600, 800 and 1000 μmol mol−1) were set to measure the parameters such as net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of single leaves. The response of WUE (Pn/Tr) to CO2 and temperature was evaluated by a CO2 response model. The results show that at the same temperature, Pn and WUE increased with CO2 level, while Tr decreased as CO2 level increases; at the same CO2 concentration, Pn and Tr were both positively correlated with temperature, while WUE decreased with the increase of temperature. The maximum value of WUE was obtained when the CO2 concentration was 1000 μmol mol−1 and the temperature was 20.0 °C. The results suggest that global warming will not improve WUE of maize, which will bring more severe challenges to water-saving agriculture and food security.

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.

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]

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]

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]

Climate change is currently considered the most important threat to sustainable development goals, particularly those goals related to the agricultural sector. The current research investigated sowing date as a strategy for adapting maize to climate change conditions in six sites of Kermanshah province characterized with a mild-arid climate using the SSM-Maize crop simulation model, HadGEM2-ES (the Hadley Centre Global Environmental Model version 2 Earth System configuration) climate model, and AgMIP (the Agricultural Model Intercomparison and Improvement Project) protocol under two emission scenarios (Representative Concentration Pathways: RCP4.5 and RCP8.5). Based on the simulation results, with temperatures rising (14% and 20% in RCP4.5 and RCP8.5, respectively) above the current threshold and CO2 concentrations increasing by 499 and 571 ppm in RCP4.5 and RCP8.5, respectively, maize yield in temperate and cold climates (all sites except Sarepol Zahab) under RCP4.5 and RCP8.5 scenarios will be decreased by -3.8% and − 6.5%, respectively. In Sarepol Zahab, the changes in air temperature and CO2 concentration increased maize yield by 11% and 21.7% in RCP4.5 and RCP8.5, respectively. Two factors influenced by climate change, namely growing season length and number of days with Tmax (maximum air temperature) ≥ 36 °C will play important roles in changing crop yield in the future. The results also showed that changing the sowing date along with increased CO2 concentration could reduce the adverse effects of climate change on maize by 15.6% across all sites, seasons, and scenarios. In fact, in all sites except Sarepol Zahab and Kangavar, sowing on the earliest possible date (April 3) helped the crop avoid encountering temperatures above 36 °C during the flowering period. In contrast, in Sarepol Zahab and Kangavar, as the hottest and coldest sites, respectively, delaying the sowing date (May 19 and June 4, respectively) could provide better conditions for crop growth. Overall, the findings of the current study showed that along with breeding activities, policy makers and extension agents of the agricultural sector can help farmers reduce the adverse effects of climate change on grain maize by compiling the cropping calendar and choosing the appropriate sowing date based on future climatic conditions. [ABSTRACT FROM AUTHOR]

For identifying the inhibiting effect of CO2 on the exothermic properties of coal oxidation at low-temperature, a Differential Scanning Calorimeter (DSC) was used to monitor the heat flows with coal temperature at different CO2 concentrations atmospheres and multiple heating rates. The results show that the DSC curve of the coal low-temperature oxidation process could be divided into three stages: rapid endothermic, slow endothermic, and exothermic stages. Compared to the air atmosphere, CO2 has different degrees of inhibition in the various stages of coal oxidation and heating. By Flynn-Wall-Ozawa (FWO) method, it revealed that the activation energy of coal oxidation decreased by 12%~19% and 10%~25% in the fast and slow endothermic stages. In the exothermic stage, the activation energy of coal oxidation increased by 20.5%~37.9%. The inhibitory effect of CO2 concentration on the exothermic stage of coal low-temperature oxidation process was superior to that in the endothermic stage. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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In order to explore the indoor air quality during different cooking procedures, a very common kitchen in China is selected for experimental research. An indoor air quality meter is used to measure the temperature, relative humidity, and CO and CO2 concentrations of the indoor air above the stove when people cook four different dishes under different ventilation patterns in the kitchen. The results indicate that the heat and gas consumed during cooking are closely related to the temperature and concentrations of CO and CO2. Some cooking procedures such as boiling water are related to the indoor air temperature and relative humidity in the kitchen. In addition, in kitchens without mechanical ventilation, natural ventilation shows a more significant positive effect on controlling temperature, relative humidity, and concentrations of CO and CO2 during cooking procedures. [ABSTRACT FROM AUTHOR]

Due to rising energy costs, there is a trend to return to conventional heating systems powered by solid fuel. A rise in the combination of new and old energy sources is creating unintended dual-fuel heating systems. These systems combine an old solid-fuel furnace and a new gas furnace. Usually, the old furnace was meant to be replaced by the new one and their cooperation was never intended when installing the new heating system. The occupants decided to leave the old system in fear of a rise in prices of gas or electricity or temporary problems with their supply. The study focuses on such a system and its influence on indoor air quality and thermal comfort. A series of dynamic measurements with an IoT remote sensor array in a chosen household was conducted to evaluate the behaviour of the system as well as effects on the indoor environment. Sensors measured the CO2 concentration and thermal profile in a household when using a dual-fuel heating system consisting of an old wood furnace from the 1980s and a recently installed new gas furnace. The results showed that none of the heat sources posed a threat to the occupants. Contaminants were safely removed by the exhaust systems of the furnaces. The thermal comfort, however, was influenced more by the wood furnace where fluctuations in the temperature were noticed, especially during the night. The gas furnace maintained a stable temperature that was more suitable for the occupants. [ABSTRACT FROM AUTHOR]

Previous studies of the effects of elevated CO2 (eCO2) concentrations and heavy metal stress conditions on plant growth and physiology have mostly focused on crops rather than vegetables. In this study, we investigated the effects of Cd stress on the growth and antioxidant system of pak choi (Brassica rapa L.), water spinach (Ipomoea aquatica Forssk.), cherry radish (Raphanus raphanistrum subsp. sativus (L.) Domin) and pepper (Capsicum annuum L.) growing in pots under ambient CO2 (aCO2) or eCO2 conditions. In general, Cd stress reduced plant biomass and SPAD values under aCO2 and eCO2 conditions; however, the reduction was smaller under eCO2. Cd stress significantly reduced vegetable superoxide dismutase (SOD) and catalase (CAT) activities under both aCO2 and eCO2 conditions; however, the decrease in cherry radish and pepper peroxidase and SOD activities and in pak choi SOD and CAT activities was significantly less under eCO2. The Cd content of the edible parts of pak choi, water spinach and pepper was significantly lower under eCO2 than under aCO2. Our data suggest that eCO2 concentrations could be beneficial for the growth of some vegetables and reduce the Cd content.

To project possible future climate change, it is important to understand Earth system response to CO2 removal, a potential key method to limit global warming. Previous studies examined some aspects of Earth system response to different scenarios of CO2 removal, but lacked a systematic analysis of the carbon cycle and climate system response in a consistent modeling framework. We expanded previous studies by using an Earth system model to examine the response of land and ocean carbon cycle, as well as a set of climate variables to idealized scenarios of atmospheric CO2 removal with different removal rates. In the scenarios considered, atmospheric CO2 increases at a rate of 1% per year to four times of its preindustrial level, and then decreases at a rate of 0.5%, 1%, and 2% per year to the preindustrial level. Simulation results show that a reduction of atmospheric CO2 induces CO2 release from both the ocean and terrestrial biosphere, and to keep atmospheric CO2 at a lower level requires the removal of anthropogenic CO2 not only from the atmosphere, but from the ocean and land carbon reservoirs as well. The response of many variables of the Earth system, including temperature, ocean heat content, sea level, deep ocean acidity, and permafrost area and carbon, lags the decrease in atmospheric CO2 ranging from a few years to many centuries. A few centuries after atmospheric CO2 returns to the preindustrial level, sea level is still substantially higher than the preindustrial level, and permafrost continues losing CO2 to the atmosphere. Our study demonstrates that to offset previous positive CO2 emissions by atmospheric CO2 removal does not mean to offset climate consequence of positive CO2 emissions. Rapid and deep reduction in CO2 emissions is key to prevent and limit increasing risks from further warming. Our study provides new insights into the carbon cycle and climate system response to CO2 removal, which would help to assess future climate change and the associated impacts.

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.

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.

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.

The Wells-Riley equation has been extensively used to quantify the infection risk of airborne transmission indoors. This equation is difficult to apply to actual conditions because it requires measurement of the outdoor air supply rate, which vary with time and are difficult to quantify. The method of determining the fraction of inhaled air that has been exhaled previously by someone in a building using a CO 2 concentration measurement can solve the limitations of the existing method. Using this method, the indoor CO 2 concentration threshold can be determined to keep the risk of infection below certain conditions. Based on the calculation of the rebreathed fraction, an appropriate mean indoor CO 2 concentration and required air exchange rate to control SARS-CoV-2 airborne transmission was calculated. The number of indoor occupants, ventilation rate, and the deposition and inactivation rates of the virus-laden aerosols were considered. The application of the proposed indoor CO 2 concentration-based infection rate control was investigated through case studies in school classrooms and restaurants. In a typical school classroom environment with 20–25 occupants and an exposure time of 6–8 h, the average indoor CO 2 concentration should be kept below 700 ppm to control the risk of airborne infection indoors. The ASHRAE recommended ventilation rate is sufficient when wearing a mask in classrooms. For a typical restaurant with 50–100 occupants and an exposure time of 2–3 h, the average indoor CO 2 concentration should be kept below about 900 ppm. Residence time in the restaurant had a significant effect on the acceptable CO 2 concentration. Given the conditions of the occupancy environment, it is possible to determine an indoor CO 2 concentration threshold, and keeping the CO 2 concentration lower than a certain threshold could help reduce the risk of COVID-19 infection. [ABSTRACT FROM AUTHOR]

Introduction: Our aim was to gain insight into the effect of COVID-19 measures on SARS-CoV-2 incidence in secondary schools and the association with classroom CO2 concentration and airborne contamination. Methods: Between October 2020—June 2021, 18 schools weekly reported SARS-CoV-2 incidence and completed surveys on school-initiated COVID-19 measures (e.g. improving hygiene or minimizing contacts). CO2 was measured in occupied classrooms twice, and SARS-CoV-2 air contamination longitudinally using electrostatic dust collectors (EDC) and analyzed using RT-qPCR. National COVID-19 policy measures varied during pre-lockdown, lockdown and post-lockdown periods. During the entire study, schools were recommended to improve ventilation. SARS-CoV-2 incidence rate ratios (IRR) were estimated by Generalized Estimating Equation (GEE) models. Results: During 18 weeks follow-up (range: 10–22) SARS-CoV-2 school-incidence decreased during national lockdown (adjusted IRR: 0.41, 95%CI: 0.21–0.80) and post-lockdown (IRR: 0.60, 0.39–0.93) compared to pre-lockdown. School-initiated COVID-19 measures had no additional effect. Pre-lockdown, IRRs per 10% increase in time CO2 exceeded 400, 550 and 800 ppm above outdoor level respectively, were 1.08 (1.00–1.16), 1.10 (1.02–1.19), and 1.08 (0.95–1.22). Post-lockdown, CO2-concentrations were considerably lower and not associated with SARS-CoV-2 incidence. No SARS-CoV-2 RNA was detected in any of the EDC samples. Conclusion: During a period with low SARS-CoV-2 population immunity and increased attention to ventilation, with CO2 levels most of the time below acceptable thresholds, only the national policy during and post-lockdown of reduced class-occupancy, stringent quarantine, and contact testing reduced SARS-CoV-2 incidence in Dutch secondary schools. Widespread SARS-CoV-2 air contamination could not be demonstrated in schools under the prevailing conditions during the study. [ABSTRACT FROM AUTHOR]

C4 plants supply concentrated CO2 to bundle sheath (BS) cells, improving photosynthetic efficiency by suppressing photorespiration. Mesophyll chloroplasts in C4 plants are redistributed toward the sides of the BS cells (aggregative movement) in response to environmental stresses under light. Although this chloroplast movement is common in C4 plants, the significance and mechanisms underlying the aggregative movement remain unknown.Under environmental stresses, such as drought and salt, CO2 uptake from the atmosphere is suppressed by closing stomata to prevent water loss. We hypothesized that CO2 limitation may induce the chloroplast aggregative movement. In this study, the mesophyll chloroplast arrangement in a leaf of finger millet, an NAD‐malic enzyme type C4 plant, was examined under different CO2 concentrations and light conditions.CO2 limitation around the leaves promoted the aggregative movement, but the aggregative movement was not suppressed, even at the higher CO2 concentration than in the atmosphere, under high intensity blue light. In addition, mesophyll chloroplasts did not change their arrangement under darkness or red light.From these results, it can be concluded that CO2 limitation is not a direct inducer of the aggregative movement but would be a promoting factor of the movement under high intensity blue light. [ABSTRACT FROM AUTHOR]

Strengthening regulations on carbon emissions from ships is important for ensuring that China can achieve its dual carbon aims of reaching peak carbon emissions before 2030 and achieving carbon neutrality before 2060. Currently, the primary means of monitoring ship exhaust emissions are the sniffing method and non-imaging optical remote sensing; however, these methods suffer from a low prediction efficiency and high cost. We developed a method for predicting the CO2 content of ship exhaust that uses a convolutional neural network and mid-infrared spectral images. First, a bench experiment was performed to synchronously obtain mid-wave infrared spectral images of the ship exhaust plume and true values for the CO2 concentration from the online monitoring of eight spectral channels. Then, the ResNet50 residual neural network, which is suitable for image prediction tasks, was selected to predict the CO2 content. The preprocessed mid-infrared spectral image of each channel and the corresponding true value for the CO2 content were input to the neural network, and convolution was applied to extract the radiation characteristics. The neural network then mapped the relationship between the true CO2 content and the radiation characteristics for each channel, which it used to predict the CO2 content in the ship exhaust. The results demonstrated that the predicted and true CO2 contents had a root mean square error of <0.2, mean absolute error of <0.15, and mean absolute percentage error of <3.5 for all eight channels. The developed model demonstrated a high prediction accuracy with one channel in particular demonstrating the best performance. This study demonstrates that the method used for predicting the CO2 content of ship exhaust based on convolutional neural networks and mid-infrared spectral images is feasible and has reference significance for the remote monitoring of ship exhaust emissions. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology 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.)

Smart and personalized ventilation systems have been demonstrated with high performance in creating a healthy and energy-efficient indoor environment, but they have been rarely comprehensively summarized and explored in previous studies. With the progressive development of various terminal devices and control technologies, personalized ventilation based on intelligent control is potentially a promising way to achieve efficient control and energy savings in human micro-environments. This study comprehensively summarizes and analyzes the recent studies and common utilization forms of smart ventilation and PV systems that are based on CO2 concentration control, to pave path and provide some guidelines for their integration application for reducing energy consumption and improving indoor thermal comfort. Research shows that the combination of personalized ventilation and smart ventilation is an essential development for ventilation systems. Smart ventilation with demand control logic based on CO2 concentration has been mature enough to effectively improve the effectiveness and comfortable performance of personalized ventilation. However, switching from traditional air conditioning systems to personalized ventilation still requires improved sensors and intelligent control algorithms. In addition, this paper also summarizes the exploratory studies and potential application analysis of machine-learning theories to improve intelligent control of personalized ventilation. To this end, this paper identifies future tendencies for advanced theories, integrated systems, and devices in personalized ventilation systems.

In this research, improvisation was carried out by modifying the market IR thermopile which functions as a thermal conductivity detector to measure the concentration of CO2 gas in the gas mixture. Four thermopiles are configured with a Wheatstone bridge with the aim of increasing the accuracy of the measurement system in detecting changes in CO2 concentration in the gas mixture (N2 and CO2). Using the bridge configuration of these four thermopiles, this measurement system can measure changes in CO2 concentration in small orders. The sensor developed is easy to manufacture, low cost, and has high linearity as evidenced by a correlation coefficient of 0.9943. From the experiments carried out, the sensor works quite accurately in detecting CO2 concentrations with the sensor’s sensitivity of -88.19 Volt/%, the detection range is 0% to 100%, and the RMS error value is 2.25.

CO2 undisputedly affects global temperature change, but the specific impact of change in atmospheric CO2 concentration on regional warming remains to be quantified, especially in different climatic backgrounds. Taking the Loess Plateau as the research area, this study quantified the effect of CO2 elevation on regional temperature change based on a single-factor sensitivity experiment of the regional Weather Research and Forecasting (WRF) climatic model, and the results revealed the following: (i) The correlation coefficient between monthly mean values of temperature simulated by the WRF model and the observed values reached 0.96 (p < 0.01), and the overall spatial trends of simulated and observed temperatures increased from the northwest to the southeast. (ii) CO2 concentration increased from 370.70 ppm in 2000 to 414.54 ppm in 2020, and the Loess Plateau region warmed by 0.04 and 0.06 °C under the MODIS land cover of 2000 and 2020, respectively. This indicates that increase in CO2 concentration over the Loess Plateau has greater impact than land cover change on regional temperature change. (iii) As CO2 concentration increased, the maximum fluctuation of temperature in summer exceeded 2.0 °C, while the fluctuations in spring (0.72 °C), autumn (0.77 °C), and winter (0.15 °C) were relatively small, indicating that summer temperature is most sensitive to CO2 concentration change. By emphasizing the marked temperature difference associated with the same CO2 change in different seasons, this study provides an important basis for extending the understanding of the differences in the effect of CO2 on regional temperatures. [ABSTRACT FROM AUTHOR]

Phytoremediation technology is an effective method to remove formaldehyde indoors, but the purification capacity and physiological response of plants to formaldehyde under the simultaneous influence of light and CO2 have not been examined in previous studies. In this study, formaldehyde fumigation experiments were conducted on the C3 plants Epipremnum aureum A. and Chlorophytum comosum L., and the crassulacean acid metabolism (CAM) plant Dieffenbachia maculate A. The phytoremediation performance and physiological response of plants were studied. The initial concentration of formaldehyde was established at 11.950 ± 1.442 m g ∙ m - 3 ; the light intensities were 448 ± 7 Lx , 1628 ± 22 Lx , and 3259 ± 22 Lx , respectively; and the concentrations of CO2 were 455 ± 29 ppm , 978 ± 50 ppm , 2020 ± 66 ppm , and 3006 ± 95 ppm , respectively. The results indicated that the highest purification rates of formaldehyde by E. aureum, D. maculata, and C. comosum were 55.8%, 43.7%, and 53.2%, respectively. The light intensity had a positive effect on the formaldehyde purification rates of all three plants and positively stimulated peroxidase (POD) activity, while the CO2 concentration had no significant impact on the formaldehyde purification capacity and plants' physiological characteristics. Exposure to formaldehyde inhibited formaldehyde dehydrogenase (FADH) activity and positively stimulated catalase (CAT) activity. The superoxide dismutase (SOD) activity positively correlated with the formaldehyde purification capacity of plants. [ABSTRACT FROM AUTHOR]

This study was conducted to examine the sensitivity of weather parameters and CO2 concentration to wheat production under two irrigation regimes viz. full irrigation and limited irrigation, using CERES-Wheat model. Field experiment data from the 2016-17 and 2017-18 rabi seasons on wheat cultivar HD-2967 with three sowing dates and five irrigation regimes were used to calibrate and validate the CERES-Wheat crop simulation model. Validation results indicated very good agreement between simulated and observed values under five, four, and three irrigations regimes as compared to lower irrigation regimes. Under full irrigation and limited irrigation, grain yield sensitivity to incremental unit of mean temperature from 1 to 3°C revealed a decrease of 6 to 22% and 8 to 16%, respectively. Temperature decreases of 1-3°C resulted in a gradual increase in yield of 10-28 and 6.5-20%, respectively, under full and limited irrigation. The combined effect of higher mean temperature and lower solar radiation revealed that wheat yield was more sensitive to temperature than solar radiation. Furthermore, the combined effect of mean temperature and CO2 level revealed that higher levels of CO2 concentration yielded the greatest benefits with a 1 °C increase in temperature, but further increases in temperature reduced the beneficial effect of elevated CO2 level under both irrigation conditions. [ABSTRACT FROM AUTHOR]

Considering the risk of infection in surgeries,maintaining an acceptable indoor air quality in Operating Rooms(ORs) to ensure the health and safety of patients and surgical team is very essential.Since air flow is one of the primary mechanisms for transmitting infections and pollution, it is crucial to examine the air distribution systems in the ORs. In the present study, the effect of Turbulent and Laminar Airflow (TAF/ LAF) systems on the air and CO2 distribution in an OR was examined. The effects of inlet and outlet configurations were evaluated for seven different models. The results indicate that the LAF systems are superior to TAF systems. Based on the findings,the LAF with the air curtain configuration brings about the minimum CO2 concentration level in the OR. The results showed that LAF with the air curtain model could reduce the CO2 concentration by about 64.66% and 88.96% on the central plane, which passes along the body patient on 1.14 m and 1.7 m above the floor, respectively, compared to the existing model. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of cadmium (Cd) stress on the growth and antioxidant system of pak choi (Brassica rapa L.), water spinach (Ipomoea aquatica Forssk.), cherry radish (Raphanus raphanistrum subsp. sativus (L.) Domin) and pepper (Capsicum annuum L.) growing in pots under ambient CO2 (aCO2) or elevated CO2 (eCO2) conditions. In general, Cd stress reduced plant biomass and soil plant analysis development (SPAD) values under aCO2 and eCO2 conditions; however, the reduction was smaller under eCO2. Cd stress significantly reduced vegetable superoxide dismutase (SOD) and catalase (CAT) activities under both aCO2 and eCO2 conditions; however, the decrease in cherry radish and pepper peroxidase and SOD activities and in pak choi SOD and CAT activities was significantly less under eCO2. The Cd content of the edible parts of pak choi, water spinach and pepper was significantly lower under eCO2 than under aCO2. Our data suggest that eCO2 was beneficial for the growth of the different types of vegetables, and at the same time, alleviated the degree of Cd stress by regulating the relative chlorophyll content and antioxidant capacity, and ultimately alleviated the adverse effects of Cd stress on the growth and quality of the vegetables. [ABSTRACT FROM AUTHOR]

Human performance and health are among the most relevant topics in modern society, especially at young ages, when academic performance is indispensable. Thus, as humans spend most of their life inside a building, thermal comfort and indoor air quality are essential aspects of a room. The aim of the current study is to numerically evaluate the main thermal comfort parameters such as PMV and PPD as well as indoor air quality, i.e., CO2 concentration, in library group study rooms at the University of Gävle in Sweden. Rotroninc Measurement Solutions CL11 sensors were utilized for temperature measurements. Simulation models were created and validated based on building data as well as temperature measurements. Several simulations were conducted throughout the year, covering different periods. The results show that even though the ventilation system, with only temperature control, works as intended for maintaining thermal comfort, the CO2 concentration rises above 1000 ppm when more than one student occupies the rooms, which is not recommended by different thermal comfort ruling institutions. Consequently, a modification to the ventilation system control is recommended, changing it from temperature control to CO2 and temperature control. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

The aim of this study was to explore the effects of elevated atmospheric CO2 concentration on the growth and medicinal ingredients of Saxifraga stolonifera, so as to provide theoretical basis for the high-quality cultivation and drug compatibility of S. Stolonifera in the future. In this study, the growth, biomass, chlorophyll content, enzyme activity, osmotic adjustment ability, N, P, K and medicinal ingredients content of S. Stolonifera were compared and analyzed under different CO2 concentrations by setting atmospheric CO2 concentration (400±10) μmol·mol-1 and increasing CO2 concentration (800±10) μmol·mol-1. The results showed that the growth and medicinal quality of S. Stolonifera were significantly changed by increasing CO2 concentration. Compared with control CO2, the plant height, root length, leaf number, petiole length and leaf thickness were significantly increased by increasing CO2 concentration, and roots, stems, leaves and total biomass were significantly increased by 9.86%, 69.65%, 14.26% and 23.46%, respectively. Under the treatment of increasing CO2 concentration, the chlorophyll content of S. Stolonifera increased significantly, which increased by 2.17% compared with the control. MDA content decreased by 3.25% under elevated CO2 treatment, while soluble sugar, soluble protein, proline content and SOD were significantly increased. The increase of CO2 concentration had no significant effect on K content in leaves of S. Stolonifera, while the content of N and P decreased significantly by 11.44% and 18.65% respectively. In addition, the content of gallic acid and bergenin and the biological yield of S. Stolonifera were significantly increased with the increase of CO2 concentration, which significantly improved the medicinal quality of it. In conclusion, with the increase of atmospheric CO2 concentration in the future, the morphological index and biomass accumulation of S. Stolonifera would be significantly increased, which would promote the accumulation of traditional Chinese medicine ingredients, and improve the medicinal and economic value of S. Stolonifera. [ABSTRACT FROM AUTHOR]

The atmospheric CO2 enrichment can seriously affect rice root growth. Alternate wetting and drying (AWD) irrigation, which can also increase root growth, is a widely promoted water‐saving technology for future climate, yet how elevated CO2 (eCO2) influences rice root growth under AWD remains unclear. In the present study, we examined the root growth of Yangdao 6 (YD 6) and Koshihikari (KOS) cultured under different water irrigation regimes (well‐watered and AWD) and CO2 concentration (400 and 800 ppm). AWD reduced shoot dry weight of KOS compared with WW under ambient CO2 (400 ppm, aCO2), while the shoot dry weight of KOS showed no difference between WW and AWD treatments under eCO2. Additional, under aCO2, AWD did not affect the exhibited similar root dry weight, length, total surface area, and volume of YD 6 and KOS relative to WW. However, under eCO2, AWD significantly promoted the root dry weight, root length, total root surface area, and root volume of YD 6 and KOS. Furthermore, root ABA content of YD 6 and KOS was significantly higher under AWD than under WW. Then, the OsNCED3 (a key gene for ABA biosynthesis) RNAi lines were used to check the role of ABA in root growth under eCO2 with AWD conditions. The results showed that AWD increased the ABA content and root parameters of WT but not the OsNCED3 RNAi lines under eCO2. Overall, the results suggest that eCO2 can improve rice root growth under AWD by involving root ABA, which contributes to the understanding of water‐saving irrigation on rice in the future climate. [ABSTRACT FROM AUTHOR]

Employing split air conditioners (SAC) for indoor heating is common, but the poor air quality usually occurs due to lack of fresh air and low relative humidity in winter. The indoor living wall (ILW) has become a reasonable option to refine the indoor heating environment through their purification and photosynthesis. To improve the heating environment, ILW were integrated with the SAC. The system integrating the ILW with the SAC (ILW-SAC) was installed in a common room with referring to the other identical room only having the SAC. The indoor thermal environment and CO2 concentration were tested, while the 72 participants were invited to demonstrate their feelings by using skin temperature measurements. The results showed that ILW-SAC significantly improved the indoor environment by increasing relative humidity by 10.8%, controlling air speed between 0.2 m/s and 0.3 m/s, and reducing CO2 concentration by 49 ppm. ILW-SAC lowered the mean skin temperature by 0.4 °C and let the mean skin temperature closer to the neutral value. ILW-SAC was found to improve the overall freshness sensation and thermal comfort level by about 1.32 and 1.10 respectively. By employing ILW-SAC, the indoor thermal environment and air quality are refined significantly in winter.

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.

In a layer house, the CO2 (carbon dioxide) concentration above the upper limit can cause the oxygen concentration to be below the lower limit suitable for poultry. This leads to chronic CO2 poisoning in layers, which manifests as listlessness, reduced appetite, weak constitution, decreased production performance, and weakened resistance to disease. Regulating ventilation may ensure a suitable CO2 concentration in layer houses. Predicting the changes in CO2 concentration and regulating the CO2 concentration in advance are key to ensuring healthy large-scale breeding of layers. In recent years, machine learning and deep learning methods have been increasingly applied to this field. A CO2 prediction model for layer house is proposed based on a GRU (gated recurrent unit) and LSTM (long short-term memory). The temperature, humidity, and CO2 were determined as inputs to the model by the correlation coefficient. The datasets of the experimental layer house were continuously measured during June–July 2023, using a self-developed environmental monitor, and the monitored data were used as samples for model inputs. There were 22,000 time series data in the datasets. In this study, multivariate time series data were standardized via data pre-processing to improve model training. GRU and LSTM models were constructed. The models were trained using a training set. Then, these trained models were used to provide predictions on a test set. The prediction errors were calculated using the true values of the test set and the predicted values provided by the models. To test the performance of the model and accuracy of the predictions, predictions were made for different numbers of datasets. The results demonstrated that the combined prediction model had good generalization, stability, and convergence with high prediction accuracy. Due to the structure of the model, the stability of the LSTM model was higher than that of the GRU model, and its prediction accuracy and speed were lower than those of the GRU model. When the datasets of the GRU model were 15,000 to 17,000, The MAE of the GRU was 70.8077 to 126.7029 ppm, and the prediction time of the GRU is 16 to 24 ms. When the LSTM model’s datasets were 15,000–20,000, the MAE of LSTM was 78.8596 to 136.0896 ppm, and the prediction time of the GRU was 17 to 26 ms.

Modeling stomatal control is critical for predicting forest responses to the changing environment and hence the global water and carbon cycles. A trait-based stomatal control model that optimizes carbon gain while avoiding hydraulic risk has been shown to perform well in response to drought. However, the model's performance against changes in atmospheric CO2, which is rising rapidly due to human emissions, has yet to be evaluated. The present study tested the gain-risk model's ability to predict the stomatal response to CO2 concentration with potted water birch (Betula occidentalis Hook.) saplings in a growth chamber. The model's performance in predicting stomatal response to changes in atmospheric relative humidity and soil moisture was also assessed. The gain-risk model predicted the photosynthetic assimilation, transpiration rate and leaf xylem pressure under different CO2 concentrations, having a mean absolute percentage error (MAPE) of 25%. The model also predicted the responses to relative humidity and soil drought with a MAPE of 21.9% and 41.9%, respectively. Overall, the gain-risk model had an MAPE of 26.8% compared with the 37.5% MAPE obtained by a standard empirical model of stomatal conductance. Importantly, unlike empirical models, the optimization model relies on measurable physiological traits as inputs and performs well in predicting responses to novel environmental conditions without empirical corrections. Incorporating the optimization model in larger scale models has the potential for improving the simulation of water and carbon cycles.

En los últimos años se ha confirmado, a través de multitud de estudios, la existencia de perjuicios graves en la salud de las personas derivados de una mala calidad del aire, lo que ha fomentado el interés en diferentes áreas para su mejora. Previamente, en el año 1987, y sus revisiones en 1997 y 2005, la Organización Mundial de la Salud [OMS) ya indicaba los principales contaminantes en el aire exterior y sus efectos adversos para la salud de las personas. Más tarde, en 2010, publicaba las directrices para espacios interiores. Establecidos estos, la organización estimaba, en 2016, que este factor es el causante de la muerte prematura de 4,2 millones de personas en el mundo. En el ámbito nacional, el estudio de la evaluación de la calidad del aire en España de 2020 constata que estos indicadores, entre los que destacan la materia particulada PM2,5 y PM1 O o el Ü 3, superaban ampliamente los valores límite recomendados por la OMS. Es por ello por lo que, el Consejo General de la Arquitectura Técnica de España ha realizado un estudio de la concentración de CO2 en viviendas, analizando diferentes factores que puedan influir en este indicador. En este caso, se presenta la relación de la concentración de CO2 con la apertura de la puerta durante el periodo nocturno, atendiendo a la exposición del usuario en el dormitorio, lo que ha permitido evaluar la diferencia de concentraciones entre los que duermen con la puerta abierta y los usuarios que lo hacen con la puerta cerrada, un factor que a priori puede parecer irrelevante, pero como veremos en los resultados tiene una gran importancia. Abstract In recent years, numerous studies have confirmed the existence of serious damage to people's health resulting from poor air quality, which has fostered interest in different areas for its improvement. Previously, in 1987, and its revisions in 1997 and 2005, the World Health Organization [WHO] already indicated the main pollutants in outdoor air and their adverse effects on people's health. Later, in 2010, it published the guidelines for interior spaces. Established these, the organization estimated, in 2016, that this factor is the cause of the premature death of 4.2 million people in the world. At the national level, the study of the evaluation of air quality in Spain in 2020 confirms that these indicators, among which particulate matter PM2.5 and PM1 O or Ü3 stand out, exceeded widely the limit values recommended by the WHO. That is why the General Council of Technical Architecture of Spain has carried out a study of the concentration of CO2 in homes, analyzing different factors that may influence this indicator. In this case, the relationship between the concentration of CO2 and the opening of the door during the night is presented, considering the exposure of the user in the bedroom, which has made it possible to evaluate the difference in concentrations between those who sleep with the door open. open and the users who do it with the door closed, a factor that may seem irrelevant at first, but as we will see in the results it is of great importance.

Rice growth at an elevated air temperature (Tair) during the ripening period is often evaluated using a semi-closed chamber (SCC). However, the water vapor pressure deficit (VPD) and CO2 concentration inside SCCs get lower than at ambient air plot, and these changes affect panicle temperature and photosynthesis. We developed a punched-top chamber (PTC), that is, an SCC with numerous pores on the top, and compared meteorological environments inside the two chambers and of ambient air plot. When solar radiation was >200 W m-2, ΔTair (SCC – Ambient) was 3.1°C–5.3°C, and ΔTair (PTC – Ambient) was 2.2°C–3.7°C. Excessively high Tair > 38°C were more frequent inside the SCC than the PTC. The changes in VPD and CO2 concentration inside the PTC were less pronounced compared with those of the SCC, and thus PTC can be a better treatment for safely assessing the direct effect of elevated Tair.