Carbon Dioxide Measurements Research Articles

Highly efficient synthetic bacterial consortium for biodegradation of aromatic volatile organic compounds: Behavior and mechanism

Aromatic volatile organic compounds (VOCs) are prevalent pollutants in chemically contaminated sites, posing threats to ecological safety and human health. To address the challenge of achieving low-carbon, low-cost, green, and sustainable in-situ remediation at these sites, a highly efficient synthetic bacterial consortium was constructed for biodegradation of selected pollutants (i.e., benzene, toluene, ethyl benzene, m-xylene, chlorobenzene, p-chlorotoluene, and p-chlorotrifluorotoluene). Under optimized conditions, the consortium achieved a total degradation efficiency of 77%. Biodegradation of benzene, toluene, ethyl benzene, and m-xylene followed first-order kinetics, while p-chlorotoluene and p-chlorotrifluorotoluene followed zero-order kinetics. The mechanisms were analyzed using microbiome technology at genetic, protein, and metabolic levels, identifying key enzymes and differences in protein expression and related metabolites. Carbon dioxide measurements and fluorescence spectrum analysis elucidated the transformation pathways. These findings underscore the consortium’s significant potential for achieving effective, eco-friendly, and sustainable bioremediation of aromatic VOCs in chemically contaminated environments.

Drought-Induced Alterations in Carbon and Water Dynamics of Chinese Fir Plantations at the Trunk Wood Stage.

Over the past three decades, China has implemented extensive reforestation programs, primarily utilizing Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) in southern China, to mitigate greenhouse gas emissions and counter extreme climate events. However, the effects of drought on the carbon sequestration capacity of these forests, particularly during the trunk wood stage, remain unclear. This study, conducted in Huitong, Hunan, China, from 2008 to 2013, employed the eddy covariance method to measure carbon dioxide (CO2) and water fluxes in Chinese fir forests, covering a severe drought year in 2011. The purpose was to elucidate the dynamics of carbon and water fluxes during a drought year and across multi-normal year averages. The results showed that changes in soil water content (-8.00%), precipitation (-18.45%), and relative humidity (-5.10%), decreases in air temperature (-0.09 °C) and soil temperature (-0.79 °C), and increases in vapor pressure deficit (19.18%) and net radiation (8.39%) were found in the drought year compared to the normal years. These changes in environmental factors led to considerable decreases in net ecosystem exchange (-40.00%), ecosystem respiration (-13.09%), and gross ecosystem productivity (-18.52%), evapotranspiration (-12.50%), and water use efficiency (-5.83%) in the studied forests in the drought year. In this study, the occurrence of seasonal drought due to uneven precipitation distribution led to a decrease in gross ecosystem productivity (GEP) and evapotranspiration (ET). However, the impact of drought on GEP was greater than its effect on ET, resulting in a reduced water use efficiency (WUE). This study emphasized the crucial role of water availability in determining forest productivity and suggested the need for adjusting vegetation management strategies under severe drought conditions. Our results contributed to improving management practices for Chinese fir plantations in response to changing climate conditions.

A-085 Comparing CO2 stability in patient samples and proficiency testing material

Abstract Background Total carbon dioxide (tCO2) measurements are important in the assessment of acid-base disorders. The collection and storage conditions of specimens are important preanalytical factors that can influence the accuracy of tCO2 measurements. Proficiency testing (PT) materials are used to assess the accuracy and reliability of a laboratory’s test performance. Unsuccessful performance on PT challenges can be an indicator of procedural issues. However, the stability of tCO2 in PT material compared to physiologic specimens is unknown and no guidance is provided to laboratories on how to handle PT samples for tCO2 measurement. This study aims to compare tCO2 stability in PT material with that of plasma samples when exposed to ambient air at room temperature. Methods Using enzymatic endpoint measurement on Vitros 4600 Chemistry System, tCO2 was measured in PT material (n = 5) and patient samples (n = 6) at baseline and after exposure to air for 15, 30, 60, 90, and 120 minutes. 500μL of each sample was aliquoted into EZ-nest tube adapters and baseline measurements were immediately analyzed. Average percent difference from baseline was calculated and >-10% bias was considered acceptable. Results The average percent difference from baseline in PT samples exceeded -10% as early as 30 minutes; whereas -3% bias was observed in patient samples at 60 minutes. Results are summarized in the table below. Conclusions The assessment of tCO2 stability ensures the reliability of laboratory measurements. Our results indicate tCO2 in PT material is not stable when exposed to air beyond 15 minutes, however tCO2 in most patient samples remained stable beyond 120 minutes. Understanding the stability limits of tCO2 in PT material allows us to devise workflows that prevent sample degradation during PT events. By establishing best practices for maintaining tCO2 integrity in PT material, laboratories can enhance the accuracy of proficiency testing results.

Uncertainties in exposure predictions arising from point measurements of carbon dioxide in classroom environments.

Predictions of airborne infection risk can be made based on the fraction of rebreathed air inferred from point measurements of carbon dioxide (CO[Formula: see text]). We investigate the extent to which environmental factors, particularly spatial variations due to the ventilation provision, affect the uncertainty in these predictions. Spatial variations are expected to be especially problematic in naturally ventilated spaces, which include the majority of classrooms in the UK. An idealized classroom, broadly representative of the physics of (buoyancy-driven) displacement ventilation, is examined using computational fluid dynamics, with different ventilation configurations. Passive tracers are used to model both the CO[Formula: see text] generated by all 32 occupants and the breath of a single infectious individual (located in nine different regions). The distribution of infected breath is shown to depend strongly on the distance from the release location but is also affected by the pattern of the ventilating flow, including the presence of stagnating regions. However, far-field exposure predictions based on single point measurements of CO[Formula: see text] within the breathing zone are shown to rarely differ from the actual exposure to infected breath by more than a factor of two-we argue this uncertainty is small compared with other uncertainties inherent in modelling airborne infection risk.

Evaluating the reliability of UAV-based carbon dioxide measurements in the lower troposphere

Vertical profiles of carbon dioxide (CO2) were captured in rural Ontario, Canada, using an Aeroqual Series 500 monitor mounted onboard an Uncrewed Aerial Vehicle (UAV). Measurements at various altitudes within the Transport Canada regulations height limit (5m – 95m) were compared to simultaneous measurements taken by an identical sensor at ground-level. Results demonstrate a high degree of agreement between onboard and ground-level observations, with a mean different of -6.02 ppm, and the majority of differences falling within the sensor’s factory calibration accuracy (±10 ppm + 5%). The study also demonstrates the ability to capture the homogeneity of CO2 in the lower troposphere, with Intraclass Correlation Coefficients (ICC) exceeding 0.75 at all altitudes, without the addition of turbulence by UAV flight. The vertical profiles captured in this study validate the use of UAV-based measurements for understanding the distribution and transport of greenhouse gases near the surface of the Earth. This research has implications for routine air quality monitoring to improve atmospheric models, environmental impact assessments and the development of targeted emission reduction strategies.

Assessment of Meat Freshness via Optical Measurement of Carbon Dioxide Using Fluorescent Capillary Coating

Assessment of Meat Freshness via Optical Measurement of Carbon Dioxide Using Fluorescent Capillary Coating

A Low-Cost Sensor Network for Monitoring Peatland.

Peatlands across the world are vital carbon stores. However, human activities have caused the degradation of many sites, increasing their greenhouse gas emissions and vulnerability to wildfires. Comprehensive monitoring of peatlands is essential for their protection, tracking degradation and restoration, but current techniques are limited by cost, poor reliability and low spatial or temporal resolution. This paper covers the research, development, deployment and performance of a resilient and modular multi-purpose wireless sensor network as an alternative means of monitoring peatlands. The sensor network consists of four sensor nodes and a gateway and measures temperature, humidity, soil moisture, carbon dioxide and methane. The sensor nodes transmit measured data over LoRaWAN to The Things Network every 30 min. To increase the maximum possible deployment duration, a novel datastring encoder was implemented which reduced the transmitted datastring length by 23%. This system was deployed in a New Forest (Hampshire, UK) peatland site for two months and collected more than 7500 measurements. This deployment demonstrated that low-cost sensor networks have the potential to improve the temporal and spatial resolution of peatland emission monitoring beyond what is achievable with traditional monitoring techniques.

Half substitution of mineral N with fish protein hydrolysate enhancing microbial residue C and N storage and climate benefits under high straw residue return

The widespread utilization of straw return was a popular practice straw disposal for highly intensive agriculture in China, which has brought about some negative impacts such as less time for straw complete biodegradation, aggravation of greenhouse gas evolution, and lower efficient of carbon accumulation. It was urgent to find an eco-friendly N-rich organic fertilizer instead of mineral N as activator to solve the above problems and lead a carbon accumulation in long tern management. Besides, microbial necromass was considered as a crucial contributor to persistent soil carbon (C) and nitrogen (N) pool. How organic fertilizer activators influence microbial residue under different amount of crop residues input remained unclear. Thus, soils incorporating moderate and high rate of rice straw residue with additions of half and full of organic activators (fish protein hydrolysates vs. manure) were incubated for measuring carbon dioxide (CO2) and nitrous oxide (N2O) emission, microbial community and necromass. It was found that soil CO2 emission was rapidest during the first 13 days of straw decomposition but remained lowest in the treatments of 50% mineral N substituted by fish protein hydrolysate. There were that 81%–89% of total CO2 release and 59%–65% of total N2O emission occurred within 60 days of incubation period, and bacterial community and nitrate positively affected soil CO2 and N2O release respectively. Straw incorporation amount and organic activator application interactively influenced soil CO2 emission but not affected soil N2O emission. After 360 days of incubation, the difference of bacterial necromass was noticeable but fungal necromass remained almost unaltered across all treatments. All treatments showed generally comparable contribution of microbial necromass N to the total N pool. The treatment of 50% mineral N substituted by fish protein hydrolysate under high rate of straw input (HSF50) promoted the highest proportion of microbial necromass C in soil organic C because of alleviating N limitation for microorganisms. Finally, HSF50 was recommended as an eco-friendly strategy for enhancing microbial necromass C and N storage and climate benefits in agroecosystems.

Urban sources of methane characterised by long-term eddy covariance observations in central Europe

Multiyear eddy covariance measurements of methane and carbon dioxide were performed in Innsbruck, Austria, a mid-sized European city in the Alps. Annual mean methane and carbon dioxide fluxes were on the order of 21.6 nmol/m2/s and 11.7 μmol/m2/s respectively. Methane fluxes increased significantly with decreasing temperature and showed a negligible weekend to weekday effect. Accompanying non-methane volatile organic compound (NMVOC) measurements provided additional constraints on urban methane sources during an intensive 6-week campaign in 2021. Positive matrix factorization analysis identified a unique and dominant methane source. Contributions from biomass burning and vehicle emissions were found to be small. No evidence was found for a large unknown biogenic source. A second intensive campaign in 2023 revealed that the measured ethane to methane enhancement in turbulent plumes showed a typical ratio of 5.2 ± 0.6%, close to the unburned ratio of natural gas (5%) in Austria. The analysis suggests that urban methane fluxes are likely to be dominated by end-user releases rather than natural gas leaks in the pipeline system. Long-term eddy flux observations also allowed identifying the existence of urban super-emitters, which brought area weighted methane fluxes up to 39 nmol/m2/s in 2022. On average, the 100 y global warming potential of methane emitted by natural gas combustion activities is 6% relative to the total urban CO2 flux, and ∼12% relative to CO2 emissions from the residential, commercial and public sectors in Innsbruck.

Shock-Layer Measurements in T5 Shock Tunnel Hypersonic Flows Around a Cylinder Model

We report on near-body measurements of temperature and nitric oxide (NO) concentration in the hypersonic flows around a cylindrical test article in the Caltech T5 reflected shock tunnel. Flow measurements were made at 50 kHz using tunable diode laser absorption spectroscopy, deploying six lasers to probe an array of quantum state-specific transitions. Laser beams were positioned both in the freestream and behind the bow shock at specific locations deemed pertinent to computational fluid dynamics comparison and kinetic model evaluation. The fractions of laser beam pathlengths behind the shock in different spatial regions were also discerned, thus providing a measurement of shock location. This study consists of six total experiments (“shots”) across two Mach ∼5 conditions, characterized by total enthalpies of 8 and 16 MJ/kg and freestream velocities of 3.5 and 5 km/s, respectively. Freestream measurements generally concur with prior works in the T5, but with some non-trivial differences. Shock-layer measurements span from 2000 to 6000 K and feature noteworthy and expected variety among different zones within the post-shock region. Thermal equilibrium is generally held throughout the flowfield, but chemical nonequilibrium is commonly observed. NO is the primary spectroscopic target, but measurements of carbon monoxide, carbon dioxide, water, and atomic oxygen provide supplementary insights.

An Innovative Prototype to Measure Carbon Dioxide, Ethylene, and Nitric and Nitrous Oxides in the Soil Air

ABSTRACT Agricultural intensification has increased the consumption of inputs, mainly fertilizers, which may increase emissions of greenhouse gases (GHG). The improvement of our knowledge on GHG dynamics in the soil is mandatory to optimize the use of fertilizers and reduce environmental impacts. We developed an electronic sensor prototype based on Arduino to monitor concentrations of carbon dioxide (CO2), ethylene (C2H4), ammonia (NH3), and nitrogen oxides (N2O/NOx) in the soil air in a greenhouse experiment with soybean (Glycine max L.) under two treatments: single inoculation (Bradyrhizobium spp.) or triple co-inoculation (Bradyrhizobium spp. Azospirillum brasilense and Pseudomonas fluorescens) in a completely randomized design. One-way analysis of variance, as well as correlation between plant traits at 35 days of emergence and the average daily concentration of gases in the soil air were performed. Although not affecting plant growth or yield-related traits, co-inoculation increased CO2, while decreased NOx concentrations compared with single inoculation, whereas C2H4 emission changed with the plant growth stage. Although co-inoculation increased respiration, decreased N losses by denitrification, mitigating the total emissions of GHG. The prototype showed to be efficient for monitoring GHG across the experiment at a low cost and easy use, contributing for monitoring GHG concentrations in the soil air.

Carbon-scaled nitrous oxide emissions better reflect the impacts of land use changes than raw nitrous oxide emissions in the Dry Chaco region

In the Dry Chaco region, agriculture expansion has caused significant land use change hotspots. However, the post-impact of land use change on nitrous oxide (N2O) emissions and carbon (C) budgets remains unknown. This study aimed to contrast the impacts of the main land use systems on N2O emissions related to its C inputs and C budgets by comparing them with those of a native forest at two sites of the Dry Chaco region of Argentina. At Site 1, the land use system were soybean-fallow-soybean and maize-fallow-maize sequences, whereas at Site 2, it was a soybean-wheat sequence. Measurements of soil N2O and carbon dioxide (CO2) fluxes were carried out monthly using the static chamber method. The C budgets of each system were determined for the annual crop-fallow cycle by the difference between the C inputs (from annual aboveground (ABG), belowground (BG), and rhizodeposition) and C outputs (defined as cumulative CO2-C emissions). At Site 1, the native forest showed 168 and 50 % more cumulative N2O emissions than maize and soybean, respectively. However, most land use differences were based on C inputs. Thus, when the cumulative N2O emissions of each system were related to their C inputs, the N2O emissions per ton of C entered of the native forest were lower than those of soybean and similar to those of maize. The C budgets (± standard error) at Site 1 were 6.4 ± 1.3, 1.0 ± 0.3 and −0.7 ± 0.6 t C ha−1 yr−1 for native forest, maize and soybean, respectively. At Site 2, they were 3.1 ± 0.7 and −4.0 ± 0.6 t C ha−1 yr−1 for the native forest and the soybean-wheat sequence, respectively. This paper proposes a comprehensive approach that integrates C inputs and budgets when evaluating N2O emissions from different land uses as a guide to define mitigating management practices and considers a native vegetation system to unmask the real impacts of agroecosystems.

Development of a Smartwatch with Gas and Environmental Sensors for Air Quality Monitoring.

In recent years, there has been a growing interest in developing portable and personal devices for measuring air quality and surrounding pollutants, partly due to the need for ventilation in the aftermath of COVID-19 situation. Moreover, the monitoring of hazardous chemical agents is a focus for ensuring compliance with safety standards and is an indispensable component in safeguarding human welfare. Air quality measurement is conducted by public institutions with high precision but costly equipment, which requires constant calibration and maintenance by highly qualified personnel for its proper operation. Such devices, used as reference stations, have a low spatial resolution since, due to their high cost, they are usually located in a few fixed places in the city or region to be studied. However, they also have a low temporal resolution, providing few samples per hour. To overcome these drawbacks and to provide people with personalized and up-to-date air quality information, a personal device (smartwatch) based on MEMS gas sensors has been developed. The methodology followed to validate the performance of the prototype was as follows: firstly, the detection capability was tested by measuring carbon dioxide and methane at different concentrations, resulting in low detection limits; secondly, several experiments were performed to test the discrimination capability against gases such as toluene, xylene, and ethylbenzene. principal component analysis of the data showed good separation and discrimination between the gases measured.

Investigation of the Relationship Between the Measured Alpha Angle in Capnography and Readmission Within Thirty Days in Chronic Obstructive Pulmonary Disease Patients Who Presented to the Emergency Department

BackgroundIndividuals with chronic obstructive pulmonary disease (COPD) constitute a significant portion of patients who present to the emergency department with dyspnea. However, there is no ideal method for predicting mortality or making hospitalization decisions in the emergency department (ED). In this regard, objective findings are needed for these patients. Since there are no objective findings regarding the hospitalization decision, there may be an increase in the re-admission rate of patients who needed hospitalization but were decided to be discharged. Side-stream end-tidal carbon dioxide (EtCO2) measurements offer a non-invasive, easy-to-interpret, quickly accessible, and reproducible method that can be applied at the bedside. ObjectivesThe aim of this study was to evaluate the relationship between the alpha angle values obtained by capnography and readmission rates within 30 days for patients experiencing COPD exacerbations who presented to the ED with dyspnea and were discharged after treatment. MethodsIn this study, we studied with 130 participants presented to the emergency department of a tertiary care university hospital with dyspnea, who are >18 y. Forty patients were excluded after evaluation for eligibility for the study. Thus, the data of 90 patients included were analyzed. We obtained alpha angle and EtCO2 values for all patients at the time of admission and also after treatment. The primary outcome measure of the study was the relationship between the patients’ readmission situations within 30 days of the alpha angle measurements. The secondary outcome measure was the association between patients’ EtCO2 values ​​and readmission within 30 days. ResultsIt was observed that both the pretreatment alpha angle values and the posttreatment alpha angle variables were statistically significant in predicting the readmission of the patients within 30 days (p = 0.001, p = 0.003) ConclusionThe results of this study show that alpha angle values measured for patients with COPD who present to the ED with the complaint of dyspnea may be used to predict readmission.

A Service-Learning Experience in Secondary Education to Promote STEM Learning Through Collaboration Between Research and Education Centers

The needs of the digital revolution and the knowledge-based economy impose a transformation of traditional education to improve technical and scientific knowledge and include alternative abilities. This work presents a service-learning initiative with multiple goals: to improve scientific, technical, engineering, and mathematic (STEM) knowledge at school, to enhance students’ engagement, and to make people aware of the repercussions of poor indoor air quality. The initiative involves four actors: the administration which steers the initiative, students who are the receivers of the knowledge, teachers as facilitators of the activity and research centers as expert references. Within this service-learning initiative, a real-life project has been proposed, focusing on measuring carbon dioxide (CO<sub>2</sub>) levels in classrooms and correlating them with indoor airborne infection transmission. Reference experts have developed two systems provided to teachers and students for project implementation. The project involves an engineering step where students set up the systems, and a scientific step where students hypothesize, develop experiments, analyse data, and communicate results gaining experience with the scientific method. Through the combined efforts and appropriate allocation of responsibilities, this experience has yielded excellent results in STEM knowledge transmission and has proven effective in fostering student commitment to their learning process.

Measurement-based carbon intensity of US offshore oil and gas production

The United States (US) produces oil and gas from six offshore regions: the North Slope of Alaska, Cook Inlet in Alaska, offshore California, and three Gulf of Mexico (GOM) sub-regions: state shallow, federal shallow, and deep waters. Measurement-based assessment of direct greenhouse gas emissions from this production can provide real-world information on carbon emissions to inform decisions on current and future production. In evaluating the climate impact of production, the carbon intensity (CI, the ratio of greenhouse gases emitted compared to the energy of fuels produced) is often used, though it is rarely quantified with measurements. Here, we complete an observational evaluation of the US offshore sector and present the largest current set of measurement-based CIs. We collected airborne measurements of methane, carbon dioxide, and nitrogen oxides from the North Slope, Cook Inlet, and California and combined with prior GOM results. For Alaska and California, we found emissions agree with facility-level inventories, however, the inventories miss some facilities. The US offshore CI, on a 100 year GWP basis, is 5.7 g CO2e/MJ[4.5, 6.8, 95% confidence interval]. This is greater than double the CI based on the national US inventory, with the discrepancy attributed primarily to methane emissions from GOM shallow waters, with a methane dominated CI of 16[12, 22] for GOM federal shallow waters and 43[25–65] for state shallow waters. Regional intensities vary, with carbon dioxide emissions largely responsible for CI on the North Slope 11[7.5, 15], in Cook Inlet 22[13, 34], offshore California 7.2[3.2, 13], and in GOM deep waters 1.1[1.0, 1.1]. These observations indicate offshore operations outside of the GOM in the US have modest methane emissions, but the CI can still be elevated due to direct carbon dioxide emissions. Accurate assessment of different offshore basins, with differing characteristics and practices, is important for the climate considerations of expanded production.

Validation of Dynamic Natural Ventilation Protocols for Optimal Indoor Air Quality and Thermal Adaptive Comfort during the Winter Season in Subtropical-Climate School Buildings

The need for energy-efficient buildings must be based on strong effective passive-design techniques, which coordinate indoor air quality and thermal comfort. This research describes the principles, simulation, implementation, and monitoring of two different natural cross-ventilation algorithm scenarios applied to a school-building case study affected by a subtropical climate during the winter season. These ventilation protocols, the steady and dynamic versions, can control the carbon dioxide concentration and actuate the window openings according to pre-defined window-to-wall ratios. The implementation of the monitoring process during three non-consecutive days in the winter of 2021 validates the opening strategy to maintain carbon dioxide below 800 ppm, described by the protocol Hygiene Measures Against COVID-19, and the temperature within the comfort ranges suggested by the adaptive UNE-EN 16798. The study shows that a steady opening of 2.16% window-to-wall equivalent ratio can be enough to maintain the requested comfort and carbon dioxide conditions. The use of the dynamic window ratios, from 0.23% to 2.16%, modified according to the measured carbon dioxide concentration, can partially maintain the carbon dioxide below the required limits for ASHRAE 62.1, Hygiene Measures Against COVID-19 and UNE-EN 16798 between 48.28% to 74.14% of the time. However, the carbon dioxide limit proposed by RITE, 500 ppm, is only achieved for 15.52% of the time, which demonstrates the inadequacy of the natural ventilation to fulfil the standard. Further improvements in the dynamic control of the openings in these buildings could lead to lower carbon dioxide concentrations while maintaining the thermal comfort in mild winter climates.

Low-cost UAV coordinated carbon observation network: Carbon dioxide measurement with multiple UAVs

Improving the mitigation of global greenhouse effects requires drastic reductions in carbon emissions. Effective carbon management at different spatial scales is therefore crucial to a more sustainable path of economic development. Regional and local carbon management currently rely on the traditional bottom-up method of emission reports, which are known for their opaque and complex procedures. Novel top-down carbon monitoring methods including space-based, aerial and ground-based observations are tantalising alternatives to more reliable data sources of carbon emissions as well as sinks. Unmanned Aerial Vehicles (UAVs) based carbon monitoring is an upcoming field because of its lower costs, higher spatial-temporal resolution and operability at a wider range of weather conditions compared to satellite observations. UAVs equipped with Non-dispersive Infrared (NDIR) carbon dioxide (CO2) sensors can measure in the air with faster response and can intelligently navigate themselves within areas of greater interest. With the help of lighter NDIR payloads and multiple UAVs flying in synchrony, larger cross sections or areas for maximising information acquisition of emission plumes can be covered. In this article, we first introduce the design of a miniaturised NDIR payload, which is compatible with a lightweight UAV to achieve a single system weighing less than 4 kg. Then, we test our design via comparisons against another NDIR payload to determine its accuracy (−0.82 ppm and −0.44 ppm) and precision (0.12 ppm and −0.03 ppm) in measurements of two vertical concentration profiles. Finally, we deployed four UAVs on two major anthropogenic emission source monitoring campaigns with coordinated flight patterns. To fully understand the benefit of multi-UAV carbon monitoring, we attempted two flight patterns and computed power plant emission rates via the cross-sectional flux method. While all flights successfully captured the concentration enhancements downwind of the power plants, the single-sectional flight pattern measured an emission rate of 10ktCO2/day which is 44% less than that reported monthly and the multi-sectional flight pattern yielded relatively varied results (8.5ktCO2/day on average, which is 54% less) for the respective sections due to wind underestimations, plume section undersampling and wind fluctuations.

Periodic open and closed resonators as a biosensor using two computational methods

The volatile particles and molecules in our dry exhaled breath can reveal enormous information about the health of any person, such as the person’s respiratory and metabolic functioning. Beyond the carbon dioxide level is an indicator of life, it provides important health-related data like people’s metabolic rate. This study considers periodic open and closed resonators for measuring carbon dioxide concentration in dry exhaled breath. Transfer matrix and green methods are used to simulate the interaction between acoustic waves and the proposed sensor. The band gaps using the green method coincide with the transmittance spectra by the transfer matrix. The suggested sensor recorded a sensitivity of 5.3Hz.m-1.s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$5.3 Hz.{m}^{-1}.s$$\\end{document}, a figure of merit of 10,254 m-1.s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${m}^{-1}.s$$\\end{document}, a detection limit of 5×10-6m.s-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$5\ imes {10}^{-6} m.{s}^{-1}$$\\end{document}, and a quality factor of 3×106\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$3\ imes {10}^{6}$$\\end{document}. Furthermore, the efficiency shows that the proposed design is appropriate as a diagnostic sensor for different diseases such as chronic obstructive pulmonary. Besides, cylindrical-adapted sensors are urgently needed in medicine, industry, and biology because they can simultaneously be used for fluid transport and detection.

Quantifying the fluxes of carbon loss from an undrained tropical peatland ecosystem in Indonesia

Conservation of undrained tropical peatland ecosystems is critical for climate change mitigation as they store a tremendous amount of soil carbon that is preserved under anoxic water-logged conditions. Unfortunately, there are too few measurements of carbon fluxes from these ecosystems to estimate the climate change mitigation potential from such conservation efforts. Here, we measured carbon dioxide (CO2) and methane (CH4) fluxes as well as fluvial organic carbon export over the peat swamp forest within an undrained tropical peatland landscape in East Kalimantan, Indonesia. Our measurements throughout one year (Oct 2022–Sep 2023) showed that despite its water-logged condition, peat and water overlying the swamp forest on average emits 11.02 ± 0.49 MgCO2 ha−1 yr−1 of CO2 and 0.58 ± 0.04 MgCO2e ha−1 yr−1 of CH4. Further, the fluvial organic carbon export contributes to additional carbon loss of 1.68 ± 0.06 MgCO2e ha−1 yr−1. Our results help improve the accuracy of carbon accounting from undrained tropical peatlands, where we estimated a total carbon loss of 13.28 ± 0.50 MgCO2e ha−1 yr−1. Nevertheless, the total carbon loss reported from our sites is about half than what is reported from the drained peatland landscapes in the region and resulted in a larger onsite carbon sink potential estimate compared to other undrained peat swamp forests. Together, these findings indicate that conserving the remaining undrained peatland ecosystems in Indonesia from drainage and degradation is a promising natural climate solution strategy that avoids significant carbon emissions.