Reduction Of CO2 Concentration Research Articles

Ruminating on the science of carbon ranching

Abstract There is interest in reducing CO2 concentrations in the atmosphere by managing livestock grazing to increase carbon (C) storage in soil. However, our understanding of the value of this practice of ‘C ranching’ is based on studies suffering substantial, overlooked methodological problems. We reviewed research into effects of grazing treatments on soil organic carbon (SOC) stocks (mass SOC × area₋1). We show the empirical basis for C ranching (C offset) projects relies mainly on studies with unrealistic and overly simplistic livestock grazing treatments (e.g. grazed vs. not grazed), suboptimal experimental designs (e.g. lack pretreatment data, low number of treatment replications) and problematic SOC stock metrics. Synthesis and applications. It is not clear that grazing treatments differ enough in their effects on soil organic carbon (SOC) stocks to reliably offset CO2 generated by human activities and/or reduce CO2 concentrations in the atmosphere. Therefore, we caution against overselling the value of carbon (C) ranching. Knowledge of C ranching effects on SOC is inadequate to justify C offset projects that provide ranchers with payment for environmental services. To better quantify benefits of C ranching, we advise using current best practices and expanding C ranching research with more realistic treatments over either broader spatio‐temporal scales and/or climate change treatments (e.g. drought, warming, elevated CO2).

The concentration of CO2 on two canopy densities in Taman Kota 1 Bumi Serpong Damai, South Tangerang

Global warming occurs because many greenhouse gases (GHG) retain heat from the earth, which causes the earth’s surface temperature to increase. The GHG contributing most to global warming is carbon dioxide (CO2) due to its highest atmosphere concentration and long life span. The increasing CO2 concentrations in urban areas are caused by transportation and industrial activities. City parks with high tree densities are the potential to reduce CO2 concentration. However, studies related to tree canopy density in reducing CO2 concentrations have not been widely carried out. This study aims to determine the CO2 concentration on two different canopy densities. This research was conducted in March - April 2021 in Taman Kota 1 BSD. Primary data collection was carried out by three replicates based on time as follows: 06.00 am, 01.00 pm, and 05.00 pm at low canopy density and high canopy density locations, respectively, by using the AZ 7725 Carbon dioxide meter tool. The low canopy density had a leaf area index (LAI) of 1.039, whereas the high canopy density had an LAI of 1.409. The highest CO2 concentration is 582.43 ppm in the high canopy density in the morning, while the lowest is 463.16 ppm occurred at the low canopy density in the afternoon. In the morning, CO2 from respiration is still concentrated under the dense canopy because there is less wind to disperse. In the afternoon, the wind speed is higher so that CO2 is more easily distributed.

On reducing CO2 concentration in buildings by using plants

The article deals with the implementation of plants in the indoor environment of buildings to reduce the concentration of CO2. Based on a specified model representing the internal environment of an office space, it was studied whether the requirement for the total amount of ventilated air could be reduced by using plants, thereby achieving savings of operating costs in the building ventilation sector. The present research describes the effect of plant implementation according to different levels of CO2 concentration of the supply air, specifically with values of 410 ppm corresponding to the year 2020, 550 ppm to the year 2050 and 670 ppm to the year 2100, as well as according to different levels of CO2 concentration in the indoor environment, namely 1000 ppm and 1500 ppm, the illumination of plants in the indoor environment is constant in the model, PPFD equals to 200 μmolm−2 s−1. Based on the computational model, it was found that the implemented plants can positively influence the requirement for the total amount of ventilated air, the most significant effect is in the case of a low indoor environment quality, with the CO2 concentration of 1500 ppm, and a high supply air quality 410 p˙pm. The simulation also showed that compared to 2020, by the year 2100, it will be necessary to increase the ventilation of the indoor environment by 25.1% to ensure the same quality of the indoorenvironment.

Effect of packaging chickpeas with CO2 modified atmospheres on mortality of Callosobruchus chinensis (Coleoptera: Chrysomelidae)

High CO2 modified atmosphere packaging (MAP) is a sustainable alternative for pest control in stored products. The effectiveness of this method varies depending on the CO2 concentration used, insect exposure time, temperature, humidity, the tested insect species, and the insect's stage of development. One factor that substantially influences the concentration of CO2 available inside the packages, and therefore the effectiveness of the treatment, is the sorption of gas in the commodity. This study evaluated the impacts of packaging chickpeas in modified atmospheres of 50% and 90% CO2 with filling ratios (proportion of grain relative to the volume of the package) of 1% and 96% grain on the mortality of C. chinensis eggs and pupae and on the fecundity of the females emerging from the surviving individuals. In packages with a 96% filling ratio, CO2 concentration in the headspace of packages reduced to 60% and 30% from initial concentrations of 90% and 50% (respectively) in the first 24 h of exposure. Despite this reduction in CO2 concentrations, no differences in the mortality of C. chinensis eggs and pupae were observed between these packages and those with a 1% filling ratio. The estimated exposure time to achieve 95% mortality (LT95) of the eggs ranged from 38 to 68 h; for pupae, it ranged from 142 to 248 h. The fecundity of females that emerged from the surviving pupae decreased after 48 h of exposure to CO2, but the fecundity of females that emerged from surviving eggs was not affected by exposure time, MAPs, or filling ratio. Therefore, effective pest control can be accomplished with the use of sufficient treatment times to eradicate the most tolerant developmental stages, regardless of whether the packages are full or not.

Towards zero carbon dioxide concentration in sweet natural gas product from amine sweetening plant

This work presents a two-step method to reduce CO2 concentration of sweet natural gas product from amine sweetening plant via amine blending (Step 1) followed by minor process modification (Step 2). In Step 1, an industrial natural gas sweetening plant was simulated using Aspen HYSYS and the simulation results were validated against the plant data. Afterwards, different blends of methyl diethanolamine and monoethanolamine (MDEA-MEA) and methyl diethanolamine and diethanolamine (MDEA-DEA) were investigated. Then the optimum amine blend of 28 wt.% MDEA and 10 wt.% MEA was reported. The optimum amine blend achieved a significant reduction in CO2 concentration of sweet natural gas of 99.9% compared to the base case (plant data). In Step 2, two types of amine stream splits, i.e., lean amine stream split and semi-lean amine stream split were studied. The study covered split stream amount, absorber recycle stage, and regenerator stage withdrawal. Both types of stream splits attained a significant reduction in CO2 concentration of sweet natural gas product and amine circulation rate compared to Step 1. However, the semi-lean amine stream split was superior to lean amine split with 69.1% and 63.6% reduction in CO2 concentration of sweet natural gas and lean amine circulation rate, respectively.

Hydrogenation of CO2 to methanol using Cu-based catalyst supported on oxide pellets

Hydrogenation of CO2 into methanol is one of the most economical process to reduce CO2 concentration in the atmosphere. Since methanol is an industrial commodity used in chemical products as well as transportation fuel, this process has gained considerable interest, which enables the effective utilization of CO2. Nevertheless, the efficiency of direct CO2 hydrogenation to produce methanol is strongly reliant on the activity of the catalyst. In this regard, the present work highlights the synthesis of methanol, catalytic evaluation and characterization of catalysts Cu/ZnO supported on Al2O3 and SBA-15 pellets with the addition of group IV, V and VII metal oxides mixture as promoters. The catalysts were systematically prepared via impregnation technique with fixed Cu:Zn and promoter ratio from group VII:V:IV. The synthesized catalysts were characterized by H2-temperature-programmed reduction (H2-TPR), field emission scanning electron microscopy (FESEM), X-ray fluorescence (XRF), N2 adsorption-desorption and N2O pulse chemisorption method. The crushing strength of the pellets were also tested. Catalytic performances were evaluated for methanol synthesis from CO2 hydrogenation in a tubular, stainless steel fixed-bed reactor at 250 °C, 2 MPa, gas hourly space velocity (GHSV) 4000 ml/g.h and H2/CO2 ratio of 3:1. The tri-promoted Cu/ZnO supported on Al2O3 pellet resulted in CO2 conversion of 13.3 % compared to 11.61 % from that of SBA-15-supported catalyst. However, the catalyst supported on SBA-15 pellet exhibited 54.59% methanol selectivity, whereas Al2O3-supported catalyst only resulted in 46.73 % methanol selectivity.

Performance of supported metal catalysts in the dimethyl carbonate production by direct synthesis using CO2 and methanol

CO2 chemical transformation is an exciting way to reduce CO2 concentration in the atmosphere. The use of CO2 to produce dimethyl carbonate (DMC), a linear, biodegradable, low toxicity carbonate via direct synthesis, is one of the most promising routes from the environmental point of view. However, DMC direct synthesis presents obstacles such as unfavorable thermodynamics and catalytic deactivation due to the water produced as a by-product. Therefore, the development and optimization of a catalytic system that can overcome these obstacles are crucial. This study investigated the catalytic activity of iron nitrate (AC-Fe), copper nitrate (AC-Cu), magnesium nitrate (AC-Mg), and nickel nitrate (AC-Ni) impregnated in activated carbon for DMC direct synthesis. Catalysts were synthesized by the impregnation method and characterized by several techniques. Simulation results evidenced the major reaction steps and simplified models of a complex involving metallic catalysts and reactants. The optimization of the catalyst amount, pressure, temperature, and recyclability of the best catalyst under optimized conditions and in the presence of different dehydrating agents was also performed. Results showed that the AC-Fe catalyst is the most efficient in the DMC direct synthesis, with a yield of 23.5 % and a selectivity of 100 % (80 °C, 40 bar, and 24 h). Reaction optimization (120 °C, 40 bar, and 24 h) using (AC-Fe) as catalyst resulted in a DMC yield of approximately 30 %. The catalytic systems recycling proved that using the dehydrating agent right combination (molecular sieve) and catalyst (AC-Fe) can maintain selectivity at 100 %, slightly decreasing yield.

Latitudinal fluctuation in global concentration of CO2 and CH4 from shortwave infrared spectral observation by GOSAT during COVID-19

ABSTRACT Various countries have rapidly implemented strict actions to slow the blowout of COVID-19. Many events were dis-regarded, and anthropogenic activities such as industrial and transport systems were at a stoppage. Many countries were on lockdown, including the largest emitters of carbon dioxide. Due to these lockdowns, anthropogenic activities have been reduced and reported that air quality improves at a regional scale in many countries, including India. Therefore, the current study using Greenhouse Gases Observing Satellite (GOSAT/IBUKI) datasets to monitor the fluctuation of the average global concentration of dry mole fractions of atmospheric Methane (CH4) and Carbon Dioxide (CO2) during these pandemic lockdowns from January to June 2020. Outputs emphasize no significant reduction in the average concentration of dry mole fractions of atmospheric CH4 over the globe, but a minor reduction was observed in global CO2 engagement. The average concentration of both gases compares at each ten-degree latitude. The study reveals that, against the regional breakdowns, these short time lockdowns are not enough to control the concentration of these greenhouse gases at a larger scale, such as 10˚ latitude and globally, except for a minor reduction in CO2 concentration.

Carbon Dioxide Footprint and Its Impacts: A Case of Academic Buildings

Carbon emissions have been considered a major reason behind climate change and global warming. Various studies report that rapid urbanization and the changing demands of 21st century life have resulted in higher carbon emissions. This study aims to examine the carbon footprints in an academic building to observe the carbon dioxide (CO2) levels at crucial landmarks and offices. A sensor-based automated system was designed and implemented for the collection of CO2 concentrations at selected locations. In the final stage, a CO2 footprint map was generated to highlight the vulnerable areas of CO2 in the academic building. It was concluded that offices have higher CO2 concentrations at both intervals (morning and afternoon), followed by the laboratory, corridors, and praying area. The CO2 concentration did not exceed 500 ppm at any location. Thus, all locations other than offices had normal CO2 concentration levels. Similarly, the humidity level was also satisfactory. The average humidity level was below 50%, which is below the permissible value of 65%. The recommended range for temperature values as per ASHRAE standards is 22.5 °C to 25.5 °C, except for prayer places. It was concluded that the selected academic institute is providing a good environment to the users of the building, but that may change once the academic institute becomes fully functional after COVID-19. This study assists the stakeholders in making guidelines and necessary actions to reduce CO2 concentration in academic buildings, as it is expected to rise once the human load increases in the next academic year. The suggested approach can be used in any other country and the results will vary based on the building type, building energy type, and building ventilation design.

Graphene nanosheets from hazardous/solid wastes: An efficient CO2 capture material

Highly efficient CO2 capture at elevated temperatures has been achieved with a few-layered graphene nanosheets (GNS) prepared from solid waste generated from high energy explosive materials manufacturing industry. These materials were used to adsorb CO2 from simulated industrial flue gases with an aim to reduce CO2 concentration in the atmosphere. The GNS is a microporous material with pore volume of 0.59 cm3 g−1 and 70% of pores were of average size of 0.55 nm. The surface area of GNS was 964 m2 g−1 which was reduced to 268 m2 g−1 when the number of layers in GNS increased to >50. The adsorption capacity of 3.89 mmol g−1 was achieved at 303 K/0.5 bar and this adsorption capacity was further increased to 23.63 mmol g−1 at 303 K/20 bar. The Sips adsorption model was used for evaluating the relationship between surface heterogeneity of GNS and adsorption capacity at temperature. The GNS materials selectively captured CO2 in the presence of gases mixtures (CO2/N2 and CO2/CH4). The fast adsorption kinetics and recycling stability of GNS for about 20 cycles suggests that the solid adsorbents prepared in this study are efficient and technically feasible to capture CO2 from industrial stacks and other real-life situations.

Effects of window opening on the bedroom environment and resulting sleep quality

The effects of two window states (closed or open) on the bedroom environment and on sleep quality were investigated. Twenty-seven subjects (14 males and 13 females, 20–33 years old) without sleep disorders and chronic diseases participated. The subjects slept for two consecutive nights with windows open and two consecutive nights with windows closed in four dormitory rooms adapted for the purpose of this study, one person at a time. The order of exposure was balanced among participants. Bed temperature, room temperature, relative humidity (RH), carbon dioxide (CO2), particles (PM2.5), and noise were monitored during sleep. Sleep quality was measured using subjective ratings, a wrist-worn sleep tracker, and (for one group of 14 subjects only) polysomnography (PSG) for home use; snoring in this sub-group and awakenings were also registered. Higher PM2.5 and noise levels were found with windows open, while higher room temperature, RH, and CO2 levels were measured with windows closed. There were no differences between conditions in terms of objectively measured sleep stages but the subjects with the PSG attached snored significantly less and woke up significantly less often when sleeping with windows open. Start sleep time, end sleep time, total sleep time (TST) and time in bed (TIB) measured with the sleep tracker were confirmed by the measurements made using PSG, light sleep (N1 + N2) and sleep latency were in moderate agreement but there was no significant agreement for REM and deep sleep (N3). When sleeping with windows open, the subjects rated the air as fresher but reported higher noise levels, feeling less rested, a worse mental state and well-being, and their replies on the Groningen sleep quality scale indicated poorer sleep quality. There was no clear association between the performance test score and sleep quality. These results suggest that sleeping with windows open can provide some benefits by increasing ventilation with outdoor air, reducing CO2 concentrations, improving air quality as indicated by the subjectively rated air freshness and some of the parameters defining sleep quality, but it may also result in some discomfort if there are episodic loud noise events outdoors. Further studies are required to clarify the role of open windows in achieving good sleep quality.

Enhanced mineral carbonation at room temperature through MgO nanocubes synthesized by self-combustion

Carbon dioxide is one of well-known greenhouse gases, which cause the global warming and climate change. Mineral carbonation with calcium or magnesium oxide (CaO or MgO) based adsorbents has been investigated to mitigate the impact of climate change on the human health and environment by reducing CO2 concentration in the flue gas and ambient air through adsorption. However, previous studies were generally conducted at higher pressure or higher temperature for applying the adsorbents to the post-capture process. In this study, we synthesized nanometer-sized crystalline MgO particles with a cubic shape (nanocubes) by an aerosol method (Self-combustion), and investigated the adsorption characteristics of the MgO nanocubes at room temperature (25 °C) by comparing with commercial MgO and CaO powders. The CO2 adsorption experiments for the three adsorbents were conducted using a batch type chamber after mixing the adsorbents with deionized water for making slurries. Based on the results of X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA), the MgO nanocubes showed higher captured CO2 per unit mass of the adsorbent than the commercial MgO and CaO adsorbents at the room temperature. Based on the comparison of the ambient hydration and carbonation processes of the two MgO adsorbents, commercial MgO showed similar carbonation kinetics with the commercial CaO. However, the MgO nanocubes showed enhanced carbonation kinetics than the other two commercial metal oxides at room temperature.

Potential Analysis of Mediterranean Forestry for Offsetting GHG Emissions at Regional Level: Evidence from Valencia, Spain

Forest management is an untapped tool, yet to realize its full potential to fight against climate change. The capability of forests to act as carbon sinks makes them a key resource to reduce CO2 concentration in the atmosphere. However, carbon which has been fixed can be suddenly emitted again as a consequence of disturbances such as pests or wildfires. Mediterranean plant phenology, climatic conditions, and the accumulation of fuel biomass due to abandonment of traditional forest uses generate a scenario prone to large wildfires and consequently large greenhouse gases (GHG) emissions. The abandonment could be offset by considering the economic value of forest ecosystem services, principally carbon fixation. Nevertheless, currently existing forest carbon markets consider only anthropogenic fixation based on a business as usual scenario without disturbances that cannot be applied to Mediterranean forest reality. Thus, a methodology to monetize carbon fixed has been developed and applied. A range between 55.5 and 250 million € produced by the monetization of 16.5 million potential carbon credits has been obtained based on anthropogenic avoided emissions produced over a 10 year-period. Thereby, the potential for offsetting emissions of the pilot region was between 1.2% and 5.6% of total diffuse GHG emissions. Consequently, sustainable forest management represents an important opportunity to combat climate change, taking advantage of the margin of improvement that the Mediterranean forests currently have to avoid GHG emissions through forest fire prevention silviculture.

External controls on CO2 in Gibraltar cave air and ground air: Implications for interpretation of δ13C in speleothems

The principles of cave ventilation and ground air advection are outlined. CO2 concentrations were monitored every 2–4 h from 2006 to 2012 at twelve locations in two Gibraltar caves, New St. Michael's (240–275 m altitude) and Ragged Staff (0–70 m), providing detailed records of spatial distribution and temporal changes responding to transient meteorological conditions and seasonal cycles. Cave atmospheres are dynamic mixtures of external air and CO2-rich ground air containing soil-respired CO2 augmented by CO2 derived from oxidation of organic matter washed down into the vadose fracture porosity. The dominant feature of the cave air records is seasonal alternation between high and low CO2 states caused by reversals in ventilation and ground air advection into or away from the caves. The high and low pCO2 states are tightly coupled between the two caves in an antiphase relationship, with rapid switching in response to temperature-controlled density differences between external air and isothermal ground air at mean annual surface temperature (18 °C). The diurnal temperature cycle modulates this pattern, producing four ventilation-advection modes. Summer and winter modes occur when diurnal temperatures are respectively entirely above or below the core temperature of the Rock. During transitional modes the core temperature lies within the diurnal range and pCO2 fluctuates rapidly as the flow of low-CO2 external air through cave entrances alters in response. Strong easterly winds reduce CO2 concentrations in ground air entering the caves and progressively lower cave air CO2. The effects of the CO2 regime on δ13C in speleothem are restricted to variations of 2–3‰, suggesting that larger changes of up to 6‰ across major climatic transitions probably reflect changes in production, transport and oxidation rate of organic matter in the vadose zone. Direct observations of these processes would improve future understanding of the climatic significance of δ13C records in speleothems.

Effect of plantation of genetically modified trees on the control of atmospheric carbon dioxide: A modeling study

AbstractThe increase in carbon dioxide (CO2) gas concentration in the atmosphere is primarily responsible for the threat of global warming. Forest is one of the prime sinks of CO2. The reduction in the global forest cover due to human activities has contributed significantly to the increase in CO2 levels. Reforestation and afforestation are avenues to control the atmospheric CO2 level; however, several demographic, ecological, and economic constraints exist in the large‐scale plantations. In this scenario, the plantation of genetically modified trees, which absorb more CO2 from the atmosphere, may aid in attaining the CO2 mitigation target. In this study, a mathematical model is proposed to investigate the effect of the plantation of genetically modified trees on the control of the atmospheric CO2 level. A comprehensive qualitative analysis of the model is carried out. The model is calibrated to fit the actual data of global CO2 concentration, population, and forest area. Numerical simulations are carried out to show the effect of key parameters on the dynamics of forest cover and atmospheric CO2 gas. The optimal strategies for the reduction in CO2 concentration while minimizing the implementation cost of plantation programs are also investigated by proposing the optimal control problem.Recommendations for Resource Managers The enhanced concentration of is primarily responsible for anthropogenic global warming. Declination in global forest cover is contributing to the increase in the concentration. Plantation of trees is an avenue to combat global warming by reducing the atmospheric level. However, plantation activities are constrained by land availability and other constraints. In this scenario, the use of genetically modified trees may aid in achieving mitigation targets. Forest plantation using genetically modified trees brings more reduction in concentration in comparison to when planted trees are not genetically modified. The forest management policies should focus on the development and plantation of genetically modified trees having more sequestration capacity, so that the carbon stock per unit forest area can be increased. Such policies are also found to be helpful in attaining the target reduction in concentration under economic constraints.

Are Cross-Border Classes Feasible for Students to Collaborate in the Analysis of Energy Efficiency Strategies for Socioeconomic Development While Keeping CO2 Concentration Controlled?

Education is critical for improving energy efficiency and reducing CO2 concentration, but collaboration between countries is also critical. It is a global problem in which we cannot isolate ourselves. Our students must learn to collaborate in seeking solutions together with others from other countries. Thus, the research question of this study is whether interactive cross-border science classes with energy experiments are feasible and can increase awareness of energy efficiency among middle school students. We designed and tested an interactive cross-border class between Chilean and Peruvian eighth-grade classes. The classes were synchronously connected and all students did experiments and answered open-ended questions on an online platform. Some of the questions were designed to check conceptual understanding whereas others asked for suggestions of how to develop their economies while keeping CO2 air concentration at acceptable levels. In real time, the teacher reviewed the students’ written answers and the concept maps that were automatically generated based on their responses. Students peer-reviewed their classmates’ suggestions. This is part of an Asia-Pacific Economic Cooperation (APEC) Science Technology Engineering Mathematics (STEM) education project on energy efficiency using APEC databases. We found high levels of student engagement, where students discussed not only the cross-cutting nature of energy, but also its relation to socioeconomic development and CO2 emissions, and the need to work together to improve energy efficiency. In conclusion, interactive cross-border science classes are a feasible educational alternative, with potential as a scalable public policy strategy for improving awareness of energy efficiency among the population.

Mesostructured Zeolites Prepared by One-Pot Top-Down Synthesis Route for Carbon Dioxide Adsorption

With the increasing emphasis on circular economies, biogas has gradually become an important energy source, but the refinement of biogas to reduce CO2 concentrations and impurities is required. This study reports on a one-pot top-down route to easily obtain mesostructured zeolite for CO2 adsorption during the biogas refinement process. Combining surfactants with an acid/base treatment achieved a perforation effect and generated mesopores in the zeolite structure. The zeolite structure and the presence of mesopores in the material were confirmed via XRD and a pore-size distribution analysis.div>

Carbon Sequestration Potentials of Man-made Grasslands under Different Pattern of Plantation Stands in West Bandung Regency, Indonesia

Alternatives of vegetations to store carbon need to be encouraged considering that forests are threatened by widespread destructions. One such vegetation is grasslands which have the potential for carbon storage and to reduce CO2 concentration in the atmosphere. At present, many enterprises have designed grasslands for many purposes. Grasslands at Cikalong Wetan and Little Farmers, West Bandung Regency were established under different pattern of plantation stands. The purpose of this research was to study the potential of carbon stock in grassland vegetation at these locations. Based on RaCSA method, the tree biomass was determined by nondestructive collection of density and basal area of trees, then calculated by an allometric equation. The ground cover biomass was determined by destructive collection of grass and roots. Total measured biomass was multiplied by 46% to obtain carbon storage. Based on the results, the potential of carbon stock in Little Farmers grassland (159,540 ton ha-1) is higher than in Cikalong Wetan (14,482 ton ha-1). Carbon stored in tree biomass gives the highest contribution to overall carbon stock potential in Little Farmers (94.84%) while carbon stored in below-ground understorey biomass gives the highest contribution in Cikalong Wetan (52.13 %). Different management of grasslands and pattern of plantation stands resulting a different contribution of carbon stock in every carbon pool. In order to maintain the carbon sequestration potentials of these locations, an agroforestry management such as agri-silviculture need to be encouraged. This study gives a comparison of the carbon sequestration potentials between two man-made grassland ecosystems. For many enterprises this study will aid in a management planning of man-made grassland in terms of ecosystem services, that is carbon sequestration.

Analysis of Indoor Air QualityBased on Low-Cost Sensors

According to WHO, indoor and/or outdoor air pollution is one of the main contributors to over two million premature deaths each year. As most of the human’s life is spent indoor, Indoor Air Quality (IAQ) - an air quality inside of a building represented by pollutant concentration and thermal condition - is one factor that needs to be concerned to sustain healthy living. In this research, we developed an Internet of Things (IoT)-based IAQ monitoring device using low-cost sensors that measure the concentrations of Carbon Dioxide (CO2), Oxygen (O2), and Particulate Matter (PM2.5). This device connects to an Android application to further observe these parameters inside two practicum laboratories in Telkom University, Bandung, for a total duration of six weeks. The location is surrounded by urban air pollution, particularly industrial activities, and residential waste burning. We also have sites of outdoor air quality monitoring system for simultaneous measurement. The environmental conditions were observed under no human activities, human intervention, and indoor plants' influence (i.e., Dieffenbachia sp.). Results show that pollutant concentrations are considerably influenced by outdoor conditions, occupancy level, and ventilation rate. Indoor plants can reduce CO2 concentrations inside the room (21-47%). On the other hand, there is no clear evidence that PM2.5 mass concentrations were affected by human activities. The bigger particles (PM >2.5 microns) probably were the ones induced by occupants during practicum. Therefore, using low-cost sensors is trustworthy to monitor IAQ for a better quality of life.

The effects of adsorbent mass using red brick powder on the results of biogas purification

Biogas is produced by the digestion of organic waste by anaerobic bacteria. However, the application of raw biogas is not effective because it consists of impurities such as carbon dioxide (CO2), hydrogen sulfide (H2S), water vapor (H2O), and other impurity gases. Physical Adsorption is the simplest method of immobilization of biomolecules such as CO2 which is attached to the surface through the weak bonds like van der Waals forces. One of the physical adsorption means to reduce CO2 levels in biogas is to use brick powder. Increasing of brick powder adsorbent mass caused the decrease of CO2 concentration in the biogas purification. Brick is a porous material containing SiO2 - Al2O3, so it has the ability to form Van der Waals bonding forces with CO2. The goal of this research is to determine the efficiency of brick powder as a purification adsorbent to reduce of CO2 levels using the 23 factorial design method. The application of 200 and 400 grams brick powder adsorbents, with the biogas flow rate of 1 and 2 liters/minute, was researched at intervals of 5 and 20 minutes, for the CO2 concentration data and heating values of biogas. Gas Chromatography (GC) was used to determine the concentration of adsorption gases, especially CO2 and CH4. The results showed that the biggest efficiency reduction in CO2 concentration is 59.28%.