Annual CO2 Emissions Research Articles

Modelling the impact of sublingual immunotherapy versus subcutaneous immunotherapy on patient travel time and CO2 emissions in Sweden

In Sweden, allergy immunotherapy (AIT) is available as either subcutaneous immunotherapy (SCIT) injections or sublingual immunotherapy (SLIT) tablets and is used to treat moderate-severe allergic rhinitis (AR). This study sought to determine treatment-related CO2 emissions and travel times in Swedish patients receiving either SCIT or SLIT-tablets. A list of specialized Swedish AR clinics that administer AIT was determined, and respective co-ordinates retrieved. Swedish municipality population data were obtained from a national database. The mean distance from each Swedish municipality to the nearest AR clinic was calculated, adjusted using a detour index, and weighted by estimated patient population size. Transport modality data were obtained from a Swedish urban transport study and CO2 emissions were obtained from Government sources. The mean number of annual SLIT-tablets and SCIT doses required were calculated based on product labels and clinical expert input. The annual number of healthcare professional interactions were layered into the model to estimate changes in mean patient travel time, distance, and travel-related CO2 emissions associated with using SCIT versus SLIT-tablets. Mean annual travel-related CO2 emissions were 410 tonnes (to two significant figures [s.f.]; standard deviation [SD] 90) with SLIT-tablets, versus 1700 tonnes (SD 380) for SCIT, resulting in mean annual savings of approximately 1300 tonnes (SD 290) of CO2 if all AIT patients were to receive SLIT-tablets instead of SCIT, over 380 times greater than 2021 average Swedish CO2 emissions per capita. Approximate mean annual travel times for patients taking SLIT-tablets were 66,500 h (three s.f.; SD 14,400), and 278,000 h (SD 60,200) for SCIT, resulting in mean annual savings of 211,000 h (SD 45,800) if all AIT patients were to receive SLIT-tablets instead of SCIT. Compared with SCIT injections, SLIT-tablets led to substantial reductions in treatment-related CO2 emissions and travel times for Swedish patients.

Techno-economic and environmental analysis of an off-grid hybrid system using solar panels, wind turbine, diesel generator, and batteries for a rural health clinic considering

Abstract Middle East has significant potential for independent solar and wind power generation due to its vast land area and dispersed settlements. Enhancing the standard of living in remote areas and meeting the increasing demand for healthcare services worldwide are crucial objectives. Finding the most reliable and affordable method of supplying energy and clean water to rural healthcare institutions is the main goal of the research. The aim of this research is to evaluate the financial and environmental impacts of employing a hybrid energy system to supply power to a clinic in Rijal Almaa, Saudi Arabia. Utilizing the HOMER software, the investigation determined that the most efficient hybrid configuration includes 360 batteries, a 25 kW DG, a 2 kW wind turbine, 33.3 kW of solar panels, and an 18.4 kW converter. The NPC (Net Present Cost) associated with this optimized system amounts to $109 307, while its COE is 0.103 $/kWh. It was found that this efficient system necessitates an initial capital outlay of $72 281, coupled with an annual operational expense of $2361. The renewable fraction (RF) of 84.7%, excess electricity generation of 8.81%, and fuel consumption of 4135 L/yr are notable features of the system. The system also exhibits the lowest annual CO2 emissions at 10825 kg/yr, indicating a positive environmental impact. The findings can be applied globally, particularly in hot, arid regions. The analysis suggests that reducing the costs of hybrid solar panels, DG, wind turbine, and battery systems could significantly reduce overall costs, making them a feasible solution for developing nations.

Meat and Bone Meal as a Renewable Energy Source in Cement Kilns: Investigation of Optimum Feeding Rate

Meat and Bone Meal (MBM) is a CO2 neutral fuel, and hence is a good candidate for substituing fossil fuels like pulverized coal in rotary kiln burners used in cement kiln systems. MBM is used in several cement plants, but the optimum substitution rate has apparently not yet been fully investigated. The present study aims to find the maximum possible replacement of coal by MBM, without negatively affecting the product quality, emissions and overall operation of the process. A full-scale experiment was carried out in the rotary kiln burner of a cement plant by varying the MBM substitution rate from 0 to 7 t/hr. Clinker quality, emissions and other relevant operational data from the experiment were analysed. Additionally, coal and MBM were compared by laboratory experiments. The results revealed that MBM could safely replace more than 40% of the coal energy without giving negative effects. The limiting factor is the free lime content of the clinker. Possible explanations to the free lime increase are given. If 40% of the coal in the rotary kiln burner was replaced by MBM on a long-term basis, the total annual CO2 emissions of the plant could be reduced by 10%.

Dual-objective optimization and energy efficiency enhancement of natural decantation assisted extractive distillation process for n-butanol/isobutanol/water separation

Isobutanol (i-BuOH) and n-butanol (n-BuOH) are widely used as solvents and organic raw materials in fine chemical and pharmaceutical fields. Hence the recovery of high-purity products from chemical industrial effluent containing i-BuOH and n-BuOH is of great significance to improve economic and environmental benefits. In this article, two extractive distillation processes with or without natural decantation are developed with 1,4-butanediol as entrainer, namely CED and NDED. In order to obtain the optimal process parameters under the trade-off between economic and environmental benefits, the two processes are optimized with total annual cost (TAC) and CO2 emissions as objective functions by a non-sorting genetic algorithm. Further, a heat integrated extractive distillation process with natural decantation and vapor recompressed heat pump is designed and investigated, namely HI-NDED-VRHP. Finally, a fair multi-criteria evaluation is conducted on all three optimal processes in terms of TAC, CO2 emissions, and total energy consumption (TEC). The results show that the HI-NDED-VRHP process is highly eco-efficient, which can reduce TAC by 18.9%, CO2 emissions 44.2% and TEC 44.7% than the CED process and decrease TAC by 12.4%, CO2 emissions 36.7% and TEC 37.1% than the NDED process.

Decadal shifts in Qingzang Plateau lake carbon dynamics (1970–2020): From predominant carbon sources to emerging sinks

The evasion of carbon dioxide (CO2) from lakes significantly influences the global carbon equilibrium. Amidst global climatic transformations, the role of Qingzang Plateau (QZP) lakes as carbon (C) sources or sinks remains a subject of debate. Furthermore, accurately quantifying their contribution to the global carbon budget presents a formidable challenge. Here, spanning half a century (1970–2020), we utilize a synthesis of literature and empirical field data to assess the CO2 exchange flux of QZP lakes. We find markedly higher CO2 exchange flux in the southeast lakes than that in the northern and western regions from 1970 to 2000. During this time, both freshwater and saltwater lakes served primarily as carbon sources. The annual CO2 exchange flux was estimated at 2.04 ± 0.37 Tg (Tg) C yr−1, mainly influenced by temperature fluctuations. The CO2 exchange flux patterns underwent a geographical inversion between 2000 and 2020, with increased levels in the west and decreased levels in the east. Notably, CO2 emissions from freshwater lakes diminished, and certain saltwater lakes in the QTP transitioned from carbon sources to sinks. From 2000 to 2020, the annual CO2 exchange flux from QZP lakes is estimated at 1.34 ± 0.50 Tg C yr−1, with solar radiation playing a more pronounced role in carbon emissions. Cumulatively, over the past five decades, QZP lakes have generally functioned as carbon sources. Nevertheless, the total annual CO2 emissions have declined since the year 2000, indicating a potential shift trend from being a carbon source to a sink, mirroring broader patterns of global climate change. These findings not only augment our understanding of the carbon cycle in plateau aquatic systems but also provide crucial data for refining China's carbon budget.

A case study of an integrated solar chimney power plant and water desalination plant in Qatar

The study proposes a novel solution of integrating a solar chimney power plant (SCPP) with a water desalination pilot plant (WDPP) to enhance generating energy and fresh water. The integration was accomplished by coupling the excess heat from the WDPP to the collector of the SCPP. Hence, enhance the temperature profile within the structure for better energy production. Hourly weather data (temperature, humidity, wind speed, and solar irradiance) were gathered during the entire year and their impacts on the efficiency of the SCPP were analyzed. The performance of SCPP+WDPP was assessed in terms of the production of electrical power and desalinated water. The temperature differences between the inside and exterior of the SCPP had a significant impact on the airflow pattern within the chimney and the resulting energy production. The results emphasized the superior performance of SCPP+WDPP, especially in terms of continuous 24-h electrical and water production. The proposed system increased water production from 139,443.4 tons to 224,513.7 tons and energy production from 633,125.9 kWh to 1,103,435 kWh compared with SCPP. The SCPP+WDPP could reduce the annual CO2 emissions by 993,091.5 kg and increased power efficiency by 98 %. Performing further techno-economic assessments is advised to enhance the system efficiency.

Design and multi-objective optimization of hybrid extractive distillation process for separating the toluene-methanol-water ternary azeotrope

Cleaner production and sustainable development are still hot topics for modern industry. Developing green technology with low energy consumption, low pollution, and low cost has always been the common pursuit of chemical, petroleum, pharmaceutical, and other industries. This article proposes an environmentally friendly and efficient solvent, glycerol, for the separation of the ternary azeotrope of toluene-methanol-water. Three feasible extractive distillation schemes were designed and optimized, while the double-column extractive distillation process with a decanter demonstrated superior performance when glycerol was used as the solvent. Additionally, the multi-objective genetic algorithm was employed to optimize these separation processes and determine the optimal operating conditions, taking total annual cost (TAC), CO2 emissions (ECO2), and separation efficiency (Eext) as target performance indicators to achieve the objectives of energy conservation, consumption reduction, and emission reduction. Results demonstrated that the newly proposed scheme can significantly reduce the total annual cost by up to 33.1 % and CO2 emissions by 50.5 % compared with the existing separation process. This work provides a new insight to separate and purify the multiple systems by extractive distillation in industry.

Exploring optimal pathways of the high-CO2 content natural gas source to chemicals and fuels using superstructure multi-objective optimization

This study aims to develop a mathematical formulation of superstructure multi-objective optimization to find optimal pathways of high-CO2 natural gas and PV-hydrogen to chemicals and fuels integrated with CO2 sequestration. A mixed-integer nonlinear programming optimization model is used to compete along 56 pathways in the superstructure optimization network. The model was developed with the general algebraic modeling system and computed with the standard branch and bound (SBB) solver to maximize annual net profit and minimize annual net CO2 emissions. The result shows the selected products in 2020 are liquefied natural gas, methanol, dimethyl ether, formic acid, and acetic acid, with annual net profits and net CO2 emissions of 38.17 million $/year and −8.47 million tons of CO2/year, respectively. In the projection analysis, the annual net profit growth results at a compounding annual growth rate of 7.85% per year between 2020 and 2060, while annual net CO2 emissions decrease until −16.37 million tons of CO2/year in 2060. In 2030, blue acetic acid will be selected via all separation processes. For 2050, the synfuel via partial membrane separation is selected. The other products, formic acid, methanol, and acetic acid via membrane separation (full and partial), will always be selected between 2020 and 2060. Therefore, this could be a future strategy for monetizing high–CO2–content natural gas sources with low-carbon process development.

Comprehensive Performance Evaluation of New Photovoltaic/Serpentine Collectors using Response Surface Methodology: Energy, Exergy, and Environmental Perspectives

Addressing the global energy demand and climate change mitigation requires novel strategies for renewable energy utilization. Photovoltaic (PV) systems harness solar power and are critical contributors to this clean energy transition. However, stand-alone PV systems capture only a fraction of the incident solar energy, thus limiting their overall energy conversion efficiency. To overcome this limitation, this study investigates the performance of integrated photovoltaic/thermal (PV/Thermal) systems that generate electricity and leverage solar energy for thermal applications. This research compares a stand-alone PV panel and six other innovative PV/Thermal configurations. Each configuration exhibits a unique serpentine-based four-compartment thermal absorber design. A comprehensive energy, exergy, and CO2 emission reduction evaluation combined with the Response Surface Methodology (RSM) technique is assessed in this study. The RSM technique generates regression models for all proposed PV/Thermal designs that can predict the output response as a function of the weather data. Finally, the Energy Payback Time is assessed for both systems to evaluate their financial feasibility. The results reveal that the uncooled PV system shows the shortest EPBT, while the PV/Thermal system offers additional benefits through combined electricity and thermal energy generation. Regarding CO2 emissions and mitigation over their lifespan, the PV/Thermal system could reduce the annual CO2 emissions by an average of 6.42 tons per year.

Performance analysis of the comprehensive energy system based on active energy storage-discharge technology under time-sharing electricity price operation strategy

Multi-energy complementary comprehensive energy systems based on renewable energy can reliably meet the energy needs of communities and significantly mitigate carbon emissions. This is of paramount significance in the establishment of low-carbon sustainable communities. The effective operation of an integrated energy system necessitates a thorough examination of demand-side load, the dynamic performance of the energy supply system, the configuration of energy storage systems, local electricity pricing policies, and operational or control strategies for the system. It confronts substantial challenges in practical application. Considering the noteworthy performance variations of comprehensive energy systems under diverse demand-side load, fluctuating electricity prices, and various operating modes of energy storage equipment, this paper initially conducts a practical analysis of demand-side load. A comprehensive energy system with multi-energy complementary based on source-load-storage coordination (SLS-CES) model was constructed. From the perspective of system operation strategy, we identify the current electricity consumption pattern in the region, characterized by peak and valley periods. We integrate this information with the time-of-use electricity pricing policy and the equipment within the target area. An operation strategy based on local time-of-use electricity price policy was proposed. An in-depth analysis of the thermal performance, environmental performance, and economic performance of the system in the full-year dimension and typical daily dimension under this operating strategy was conducted. The results show that under this operation strategy, the system's annual net income is 415.90 thousand yuan, of which the system's energy storage battery power supply revenue during peak period reaches 254.40 thousand yuan. The initial investment is 5.03 million yuan, and the static investment payback period is 12.09 years. The annual primary energy saving rate of the system is 36.00%, and the maximum CO2 emission reduction rate is 72.23%. The maximum primary energy saving rates on typical days in winter and typical days in summer are 74.74% and 97.14% respectively. The total annual CO2 emissions were reduced by 5.47 tons and 4.54 tons respectively. Through this study, we found that a system incorporating energy storage equipment, combined with an operation strategy based on electricity price policy, can yield additional economic benefits. This approach helps alleviate peak power supply pressure on the grid and mitigates the challenges associated with the high initial investment in renewable energy systems, all while maintaining good thermal performance and environmental benefits.

Numerical performance investigation of High Vacuum Flat Plate Hybrid Photovoltaic-Thermal devices.

We propose an innovative flat plate hybrid Photovoltaic-Thermal system under high vacuum (HV PV-T) optimized for solar-to-thermal energy conversion. It consists of a glass cover, metallic vessel, and the actual PV-T device, which englobes a low-emissive Transparent Conductive Oxide (TCO), a perovskite-based PV cell, a Solar Absorber, and a copper substrate. We investigate, through a 1-D model developed in MATLAB, the performances of the proposed PV-T system, still mined by radiative losses, varying the operating temperature (Top) and the emittance of the TCO (εTCO ) in the ranges of (25÷175) °C and (0.05÷0.45) respectively. The annual thermal and electrical productions are evaluated considering the Typical Meteorological Year of Naples, Italy. Specific annual costs and emission savings are evaluated and compared with the ones assured by commercial High Vacuum Flat Plate Solar-Thermal (HVFP ST) and PV collectors. Results indicate that the proposed HV PV-T increases the annual cost savings by 34% and 11% when compared to HVFP ST and PV collectors, respectively. Moreover, the presented HV PV-T increases the annual CO2 emissions savings by 7% and 48% when compared to HVFP ST and PV collectors, respectively.

Grid aided combined heat and power generation system for rural village in north China plain using improved PSO algorithm

The rural areas of North China Plain, an important grain producer in China, are endowed with abundant new energy resources such as biomass, solar, and wind energy. The revitalization of the rural villages is confronted with the shortage of clean and low carbon energy supply. This work proposes a multi-energy complementary distributed energy system (DES) tailored for daily energy consumption in a typical scattered village on the basis of the field survey results. The geothermal heat pump, photovoltaic system (PV), biomass gasification equipment, and other energy conversion devices are integrated in the DES model. The state grid is used as a fundamental ensuring resource to improve the robustness of the system. The improved particle swarm optimization (PSO) algorithm is employed to determine the optimal unit capacity configuration by examining investment cost, payback period, system self-sufficiency, accommodation rate, and annual CO2 emissions. The main available renewable energy resources are biomass and solar energy with the annual amount of 1608.9 tons and 1679 kW h/m2. The heat, gas, and electricity load account for 76.84%, 3.14%, and 20.02%, respectively. Based on the daily peak-to-valley price differentials in Beijing of over $0.15/kWh, DES optimization was carried out with PSO module in MATLAB software. The cost of the energy supply with DES, Scenario 3, was compared with that of the mere grid and renewable systems, Scenario 1 and Scenario 2. The direct DES cost is $0.52 million with the internal rate of return of 8.46%, resulting in a payback period of 6.15 years. The overall system self-sufficiency index except for grid achieved a value of 0.42. The application of the DES lead to energy costs of residents and annual carbon emission reduction by 32.5% and more than 3800 tons, respectively, compared to grid-only energy consumption, showcasing the feasibility of grid-aided combined heat and electricity production in rural areas.

Addition of biochar decreased soil respiration in a permanent no-till cover crop system for organic soybean production

The increase in soil carbon sequestration under long-term no-till (NT) and cover crop management has been shown to form part of a sustainable agricultural management practice system. Along with the increase in soil organic carbon (SOC), soil respiration in this system was also enhanced by the increased soil temperature through the decomposition that causes carbon loss from the soil. To overcome this issue, biochar can be applied. However, the addition of biochar into this system is not well studied. Therefore, the aim of this study was to investigate the effect of this system on soil respiration. The experiment was conducted at the Center for International Field Agriculture Research & Education, Ibaraki University. Long-term tillage practices, such as NT and moldboard plowing (MP), cover crops such as rye (RY) and fallow (FA), and biochar application such as with biochar (WB) and no biochar (NB) were applied to a split–split plot in a randomized complete block design with four replications. The daily CO2 flux was measured every week at 9:00–11:00 a.m. The daily soil respiration was affected by tillage and cover crop with NT practice had significantly higher daily CO2 flux than that of MP (23.8%–107.4% and 38.0%–107.8%), while RY had higher flux than that of FA (11.9%–81.2% and 34.9%–65.4%) in 2020 and 2021 soybean growing season, respectively. Additionally, in the 2020 cover crop growing season RY also increased daily CO2 flux approximately 41.8%–88.2% compared to FA. Biochar addition significantly reduced soil respiration in soybean and cover crop seasons compared to NB by 24.0%–50.7% and by 25.9%–48.3%, respectively. This reduction in soil respiration by the biochar decreased annual CO2 emissions by 17.6% and 13.0% in 2020 and 2021. The values of these emissions ranged from 9.6 Mg ha−1 for MP FA WB to 18.9 Mg ha−1 for MP RY NB in 2020 and from 7.5 Mg ha−1 for MP FA WB to 13.7 Mg ha−1 for NT FA NB in 2021. This study highlights the crucial role of biochar in reducing soil respiration and enhancing SOC sequestration. The addition of biochar into this system was able to reduce soil respiration by regulating the soil temperature, soil moisture, and protect the SOC from decomposition. Biochar addition also increased the SOC and decreased the soil bulk density, which improves soil porosity. Therefore, these findings would be very useful to be included within the global scenario of soil organic matter management.

Nearly zero energy building design and optimization: A residential building transformation in Türkiye

In this study, the energy performance analysis of a representative residential building located in Izmir, Turkey, was carried out, utilizing the DesignBuilder energy simulation program. Heating, ventilation, and air conditioning systems are modeled as detailed in Design Builder in order to consider parameters such as thermal properties of materials, duct layout and airflow dynamics of the system in detail in the analysis. The technical and economic analysis of transforming the building into a nearly zero energy building (NZEB) was performed for eight different retrofit scenarios, including passive and active energy efficiency measures. The most effective scenario, Scenario 8 (S8), reduced the building's annual net primary energy consumption by 96.08% to 7.45 kWh/m²/year. S8's annual CO2 emissions decreased by 100.07% compared with the reference scenario, resulting in −0.042 kg CO2/m²/year. The overall energy performance class of the building was determined using Turkey's national calculation program for the preparation of the energy identity certificate. The energy performance class of the reference building was determined as D, and the class of the building designed according to S8 as A. Investment evaluations were carried out for the retrofit scenarios, revealing that the investment cost for S8, having the lowest net primary energy consumption, amounted to USD 17,565.87. This finding establishes S8 as a more financially viable option in the short term. This study demonstrates the potential of NZEBs in reducing greenhouse gas emissions and achieving sustainable development goals.

Light-Induced Ammonia Generation over Defective Carbon Nitride Modified with Pyrite

The challenge to mitigate climate change and to limit global warming to well below 2 °C according to the Paris Agreement, requires a reduction of greenhouse gas emissions not only in transportation, but also in industry.[1] The Haber-Bosch process for the production of ammonia, NH3, is one of the most important industrial processes, but significantly contributes to the world’s annual CO2 emissions.[2] Photocatalytic reduction of dinitrogen (NRR) offers a sustainable alternative for the synthesis of ammonia. Some of the highest activities so far were achieved with carbon nitride (C3N4) photocatalysts, especially after the introduction of nitrogen vacancies.[3] Carbon nitrides are earth abundant, non-toxic, low-cost polymeric materials, with a suitable band gap for visible light absorption. To overcome the inherently fast charge carrier recombination that diminishes the efficiency, heterojunctions with a second photocatalyst are widely investigated.[4] Another common approach in the design of photocatalyst for the NRR is nature-inspired. Herein, mainly sulphur, iron and molybdenum containing materials are investigated, inspired by the composition of the active centre in nitrogenase enzymes.[5]In this contribution we present composite materials of FeS2 and vacancy-rich VN-C3N4, thereby combining both strategies of heterojunction formation and bio-inspiration, as well as that of defect engineering in C3N4, to increase the number of active sites.[6] The composites yield significantly higher amounts of ammonia after light irradiation for 7 h, compared to both FeS2 and VN-C3N4 alone. Hydrogen is produced as the only by-product. A combination of control experiments and material characterisation before and after light irradiation revealed that iron in FeS2 coordinates to VN-C3N4 at the defect site. Cyano-groups at these sites are activated via π-back-donation and subsequently converted into ammonia. Thus we could prove that – at least initially – ammonia is generated not from the N2 gas, but from the C3N4-framework itself.

Low carbon dioxide emissions from aquaculture farm of lake revealed by long-term measurements

Fast-growing global aquaculture has resulted in eco-environmental costs, one of the key concerns is carbon emissions. Freshwater lakes have been long used for aquaculture, and CO2 emissions from the system should be assessed to better understand the role of aquaculture in carbon budget. Here, CO2 emissions from aquaculture farm and open water of a lake in eastern China were investigated with long-term (2000–2017) field samplings. Positive correlation between annual CO2 emissions and dissolved organic carbon (R2 = 0.63, p < 0.01) occurred at aquaculture farm, suggesting feed-derived carbon application contributed to aquaculture CO2 emissions. But unexpected lower CO2 emissions (8.01 ± 5.28 mmol m−2 d−1) occurred at aquaculture farm compared with emissions from open water (11.58 ± 7.42 mmol m−2 d−1). Although temporal variation of CO2 emissions was negatively correlated with chlorophyll-a at non-aquaculture region, a reciprocal relationship with dissolved oxygen level (R2 = 0.35, p < 0.01) was found at aquaculture farm, which was attributed to the presence of aquatic vegetation used for the aquaculture. Meanwhile, positive correlation between annual CO2 emissions and nutrient was found, and aquatic vegetation planting in the aquaculture may reduce the CO2 emissions via direct photosynthesis and indirect ways of such as absorbing nutrient. The findings suggested that the two aquaculture management actions (feed addition and vegetation planting) are two antagonistic processes in the CO2 emissions, likely lead to the aquaculture farm as relatively low CO2 source. Our results may provide an informed solution for the tradeoff between CO2 emissions and aquaculture production.

Assessment of the Emission Characteristics of Major States in the United States using Satellite Observations of CO2, CO, and NO2

By using space-based measurements of the column-averaged dry air mole fraction of carbon dioxide (XCO2) from the Orbiting Carbon Observatory-2 (OCO-2) and CO and NO2 from the Tropospheric Monitoring Instrument (TROPOMI), this study investigates the seasonal variation in the characteristics of CO2, CO, and NO2 across major states in the United States. Beyond correlating these trends with natural factors, significant emphasis is placed on human activities, including heating demands, energy usage, and the impacts of the COVID-19 pandemic. Concentration enhancements in observations influenced by anthropogenic emissions from urban regions relative to background values are calculated to estimate gas emissions. Our investigation reveals a strong correlation between NO2 and CO2 emissions, as evidenced by a correlation coefficient (r) of 0.75. Furthermore, we observe a correlation of 0.48 between CO2 and CO emissions and a weaker correlation of 0.37 between CO and NO2 emissions. Notably, we identify the NO2 concentration as a reliable indicator of CO2 emission levels, in which a 1% increase in NO2 concentration corresponds to a 0.8194% (±0.0942%) rise in annual mean CO2 emissions. Enhancement ratios among NO2, CO, and XCO2 are also calculated, uncovering that high ΔNO2: ΔXCO2 ratios often signify outdated industrial structures and production technologies, while low ΔCO: ΔXCO2 ratios are linked to states that utilize clean energy sources. This approach offers a deeper understanding of the effect of human activities on atmospheric gas concentrations, paving the way for more effective environmental monitoring and policy-making.

An appropriate amount of straw replaced chemical fertilizers returning reduced net greenhouse gas emissions and improved net ecological economic benefits

With the increasing application of crop straw, the greenhouse gas emissions caused due to crop straw have received increasing attention. However, the current studies have not explored the greenhouse gas emissions from on-farmland consumption of returned straw. Based on a long-term positioning experiment, three treatments were set up in double-cropping rice fields: chemical fertilizer (CF), straw replacing 1/3 nitrogen fertilizer (MS), and straw replacing 2/3 nitrogen fertilizer (HS). We measured the biomass, soil properties, and greenhouse gas emissions of double-cropping rice and then comprehensively evaluated the global warming potential, carbon footprint, and net ecological and economic benefits. The straw treatments (MS and HS) increased the cumulative annual emissions of CH4 (98.44% and 261.23%), CO2 (30.85% and 122.29%), and N2O (7.37% and 52.50%), the cumulative annual global warming potential (74.15% and 206.12%), average GHG intensity (43.26% and 138.07%), and the annual cumulative net ecosystem carbon budget (52.96% and 100.97%) in the early and late rice growing seasons, respectively. We observed that the real-time greenhouse gas emissions were significantly correlated to the soil microbial functional genes and total carbon, NH4+-N, and NO3−-N. The results of the random forest model showed that total carbon (13.87%) and nirK abundance (9.80%) were the highest predictors of global warming potential at the booting and maturity stages, respectively during rice growing season. Combining the resource inputs for agricultural production and the greenhouse gas emission potential of the returned straw on its own, MS showed the lowest net greenhouse gas emission, and MS and HS showed significantly increased annual cumulative net ecological economic benefits (38.08% and 34.30%). Overall, MS showed the lowest net greenhouse gas emission and the highest net ecological economic benefits, which is a straw-returning measure with low environmental impact and high economic returns.

3D-printed polylactic acid-microencapsulated phase change material composites for building thermal management

The integration of phase change materials (PCM) into architectural elements is an emerging strategy to enhance thermal energy storage in modern buildings. This research examines 3D-printed polylactic acid structures incorporated with microencapsulated PCM, targeting a more efficient thermoregulation in foundational architectural sections such as walls, floors, and ceilings. Through rigorous evaluations, the polylactic acid-PCM composite revealed promising thermoregulatory properties. Notably, latent heat values stood at 198.4 J/g for melting and 197.9 J/g for freezing. Real-world experiments demonstrated a distinct advantage, maintaining temperatures 3.2°C–3.3 °C higher than standard polylactic acid at night and exhibiting a cooler range of 10.4 °C–13.3 °C during daylight. Within specific geographical contexts, like the Mediterranean and Aegean Seas coastline, 0.026 m thick polylactic acid-PCM panels stood out, registering 100 % energy savings. The findings consistently showed that an increase in panel thickness correlated with a decrease in building heating needs. Further analysis explored the carbon emissions landscape. Coal, when utilized with 0.05 m-thick polylactic acid-PCM panels, was identified as particularly effective, yielding a reduction of 34 kg/m2 in annual CO2 emissions. Collectively, the findings underscore the transformative potential of polylactic acid-PCM composites, positioning them as pivotal tools for advancing architectural energy efficiency and fostering sustainable building innovations.

Thermal insulation and energy performance's assessment of a mycelium-based composite wall for sustainable buildings

Bio-composite insulation materials play a crucial role in reducing the environmental impact of buildings. This paper numerically investigates the eco-friendly application of mycelium in south-facing walls in Marrakech, Morocco, using 2D CFD simulations. In this context, the thermal efficiency of bio-sourced insulating materials was assessed and compared to that of conventional insulating materials. The study basically aims at the time lag and the decrement factor analysis to evaluate the dynamic thermal performance of a multilayer wall insulated with mycelium. A life cycle cost analysis (LCCA) is performed to establish the optimal thickness of the mycelium insulation, which was turned out to be 0.08 m. This optimization leads to a substantial improvement in energy efficiency, resulting in energy savings increasing by 87.4 % in winter and 55.9 % in summer. Besides, during the last 72 h of the simulation, the indoor surface temperature drops by approximately 4 °C on summer days and raises by approximately 1 °C on winter days. The thickness of mycelium insulation was found to have a significant impact on energy savings, increasing them from 56 % to 93 %, and representing nearly a 1.7-fold improvement. The study has also targeted annual CO2 emissions to reveal a potential reduction of around 72 % using optimal mycelium composite insulation. Finally, a comparative analysis with the guidelines of Moroccan thermal regulations was achieved. The obtained findings exhibit that the examined configuration excels in terms of thermal performance, economic feasibility, and environmental benefits.