Mean CO2 Concentration Research Articles

Determination of metals in water samples within the irrigation area in Telo District, Kaffa Zone, South Western Ethiopia

Water contamination due to the accumulation of metal is not only an environmental problem, but it is also a global issue. The river flows alongside the town in its downward direction, where runoff from the uplands and municipal trash discharge during floods may contribute to the contamination of the river. Despite the fact that this river is the area's primary source of water, the water near the effluent release point is extremely corrosive. The nearby settlements depend on this untreated river water for drinking, irrigation, and other domestic uses since they have no access to a municipal water supply. The aim of the present study was to evaluate the degree of metal contamination in the Obasho river water samples collected from irrigation water sites in the Gurguba region. Three samples were collected from each of four irrigation water sites, which were 1.5 km away from each other. A total of 12 water samples were collected by following the standard water sample collection protocol. 100 mL of the irrigation water sample was digested in aquaragia, and AAS was used to determine the concentration of metals in the water samples. The concentration ranges of some metals were: Ca (1.84387–2.810824 mg/L), and its maximum limit in FAO is 20.0 mg/L; Mg (3.176942–4.543031 mg/L), and its maximum limit in FAO is 5.0 mg/L; Cr (0.039227–0.047872 mg/L), and its WHO/FAO permissible level is 0.1 mg/L; Co (0.036703–0.057218 mg/L), and its permissibility level is 0.05 mg/L WHO/FAO, Cd (0.006198–0.02856 mg/L), whose maximum limit in FAO is 0.01 mg/L, and Pb (0.065138–0.091131 mg/L) WHO/FAO permissible level is 5.0 mg/L. The mean concentrations of metals (Ca, Mg, Co, Cd, Pb, and Cr) in all study sites were below the regulatory limits except for Co and Cd; no water contamination was caused by these metals at the study sites. However, the mean concentration levels of Co in all study sites were above regulatory limits. The mean concentration of Co at Konit Kochito and Cd at Geremew Mamo, Konit Kochito, and Gereno Gebito is also greater than regulatory limits. A pair-wise comparison of some metals in study sites was carried out, thus the mean concentration of the irrigation water sites sample was significantly different from some metal concentration (p < 0.05) at the 95% confidence level. Generally, there was no cumulative effect of water contamination caused by Ca, Mg, Co, Cd, Pb, and Cr in Gurguba Kebele study sites, and it may not appear to pose very serious environmental problems at this moment. Thus, determining the metal content in irrigation water samples is crucial for ensuring the safety and sustainability of agricultural practices. It raises awareness regarding the contents of heavy metal contamination and sets limits for acceptable metal concentrations. It has also vital role in maintaining soil health.

ML‐Based Hybrid SAR and Optical Image LULC Mapping and Change Analysis With Variations in the Air Quality of the Imphal Valley, North‐East India

AbstractImphal Valley, situated in Manipur, India, stands as an intermontane valley of great ecological significance, notably hosting Loktak Lake. This research delves into the Land Use Land Cover Change (LULCC) within the Imphal Valley from 2016 to 2021 and assesses their impact on air quality across distinct land cover types. We used Sentinel‐1 &amp; 2 data, ALOS PALSAR Digital Elevation Model, and applied Random Forest (RF), a machine learning algorithm for effective land use and land cover (LULC) mapping. Additionally, Sentinel‐5P data was utilized to monitor air quality parameters (CO, HCHO, NO2, SO2, Aerosol Index) spanning 2019 to 2021. The overall accuracies for the LULC maps employing a k (k = 3) fold approach for accuracy assessment varied between 88% and 92%, with corresponding Kappa coefficient ranging from 0.85 to 0.90. Noteworthy trends emerged from our analysis, revealing an increase in settlements and horticulture farms and a decline in forested areas and phumdis (floating biomass). Our findings highlight a mean concentration of CO ranging between 0.045 mol/m2 and 0.055 mol/m2 in different land cover types during February and March (2019–2021). Furthermore, we observed maximum mean HCHO, NO2, SO2, and aerosol index concentrations in March. Pollution levels surged during forest fires and shifting agriculture seasons, while aerosol levels declined during the lockdown period. This integrated approach emphasized on the comprehensive analysis of the dynamic interplay between LULCC and air quality in the Imphal Valley. This intricate relationship between LULC changes and air quality dynamics in the Imphal Valley, contribute to our understanding of the environmental dynamics in this ecologically vital region.

Trace mineral concentration of forages in connection with sheep dietary requirements

This paper describes the trace and ultra-trace mineral concentration in different forages utilized by sheep (Kajli and Fat tail) in the rangelands of Chakwal district, Punjab, Pakistan. The concentrations of Se, Mo, Zn, Mn, Cu, and Co were assessed using spectrophotometric methods after the digestion of forage samples. The dominant forage species consumed by sheep were Buxus pappillosa, Prosopis juliflora, Ficus palmata, Acacia modesta, Trichodesma indica, Olea permiginea, Lantana camara, Justicia adhatoda, Morus nigra, and Ipomoea carnea. The overall mean concentration of Co (1.27±0.24 mg/Kg of DM), Zn (35.14±1.28 mg/Kg of DM), and Cu (28.06±1.29 mg/Kg of DM) in forages were higher than the requirements for lactating ewes, while the concentration of Se was within the normal range. Molybdenum (0.030±0.004 mg/Kg of DM) and Mn (29.69±1.61 mg/Kg of DM) concentrations were lower than dietary requirements for sheep. In different administrative divisions (tehsils) like Chakwal, Talagang, Choa Saidan Shah, and Kalar Kahar of Chakwal district, the trace minerals Zn, Mn, and Co, showed non-significant variation, whereas Se, Mo, and Cu showed substantial variation. In conclusion, rangeland forages contained a sufficient concentration of most trace minerals (Co, Cu, Se, Zn) to meet the requirements of grazing sheep in the study district. However, Mn and Mo supplementation seems to be essential to maintain the optimal production capabilities of sheep in this area.

Greenhouse gas levels (CH4 and CO2) in Lagos state and Oyo state, Nigeria

The proliferation of greenhouse gases has emerged as a grave menace to humanity. According to scientists, the concentration of these gases, particularly carbon dioxide and methane, is directly linked to the rapid pace of global warming and climate change. To investigate this matter, a study was conducted utilizing a portable gas detector to measure the levels of carbon dioxide and methane in four locations each in Ibadan and Lagos for three months. Readings were collected at each sampling site three times, with each collection period lasting 5 to 15 min. These readings were taken at intervals of 2 to 3 h over a period of 3 months, while also exploring their correlation with meteorological parameters (Temperature, wind speed and relative humidity). Farms, airports, residential areas, and dump sites were deliberately selected due to their contribution to greenhouse gas emissions. The study yielded the following mean concentrations of CO2 in Lagos: 717.67 ppm in Residential Areas, 751.78 ppm in Farmland, 743.78 ppm at the Airport, and 732.56 ppm at the Dumpsite. Similarly, the mean concentrations of CH4 were 0.14 ppm, 0.30 ppm, 0.36 ppm, and 0.45 ppm, respectively. In Ibadan, the average CO2 concentrations were 676.44 ppm in residential areas, 765.11 ppm in farms, 653.33 ppm at the airport, and 683.67 ppm at the dump site. The average CH4 concentrations were 0.08 ppm, 0.32 ppm, 0.43 ppm, and 0.30 ppm, respectively. Furthermore, significant relationships between CO2 and CH4 with meteorological parameters were observed, with R2 values of 0.200 for CO2 in Ibadan, 0.08 for CO2 in Lagos, 0.56 for CH4 in Ibadan, and 0.35 for CH4 in Lagos. Cities, farms, airports, and landfills are responsible for substantial greenhouse gas emissions. The massive release of CO2 and CH4 has resulted in profound impacts and consequences that fuel climate change. This research provides valuable insights into the issue, consequences, and mitigation strategies pertaining to the reduction and regulation of CO2 and CH4 emissions in Lagos and Ibadan, Nigeria.

Local Reaction Environment Deviations within Gas Diffusion Electrode Pores for CO2 Electrolysis

The local conditions inside a gas diffusion electrode (GDE) pore, especially in the electrical double layer (EDL) region, influence the charge transfer reactions and the selectivity of desired CO2ER products. Most GDE computational models ignore the EDL or are limited in their applicability at high potentials. In this work, we present a continuum model to describe the local environment inside a catalytic pore at varying potentials, electrolyte concentrations and pore diameters. The systems studied in this work are based on an Ag catalyst in contact with KHCO3 solution. Our study shows that steric effects dominate the local environment at high cathodic potentials (≪−25 mV vs pzc at the OHP), leading to a radial drop of CO2 concentration. We also observe a drop in pH value within 1 nm of the reaction plane due to electrostatic repulsion and attraction of OH− and H+ ions, respectively. We studied the influence of pore radii (1–10 nm) on electric field and concentrations. Pores with a radius smaller than 5 nm show a higher mean potential, which lowers the mean CO2 concentration. Pores with a favourable local environment can be designed by regulating the ratio between the pore radius and Debye length.

Off-Gassing and Oxygen Depletion in Headspaces of Solid Biofuels Produced from Forest Residue Biomass

As living standards improve worldwide, the demand for energy increases. However, climate changes and decreasing fossil fuel deposits have increased interest in renewable energy sources, including pellets produced from forest residues. This study aimed to compare changes in concentration of gases (CO, CO2, O2, volatile organic compounds—VOCs) in enclosed headspaces above pellets produced from deciduous (oak OA, birch BI) and coniferous (pine PI, spruce SP) dendromass and selected types of commercial pellets during their storage. The experiment measured the concentration of gas released from the pellets in storage daily for 14 days. The highest mean CO concentration was found for PI pellets (1194 ppm), and the lowest was for OA (63.3 ppm). Likewise, the highest CO2 concentration was noted for PI pellets (4650 ppm), and the lowest was for BI (1279 ppm). The largest VOC amount was released in the headspace above PI (88.8 ppm), and the smallest was above BI (4.6 ppm). The oxygen concentration was the lowest as measured for PI (minimum 16.1% v/v) and for SP (19.3% v/v). The threshold limit value (8 h) for CO was exceeded for all the pellets under analysis and, in the case of CO2, only for PI after day 10 of incubation. The study findings are extremely important from a scientific (but mainly from a practical) perspective because of the safety of storing and transporting wood pellets. The knowledge of autooxidation processes in those biofuels can help organize their logistics and storage and result in proper warehouse ventilation and monitoring of noxious gases.

Impacts of Biomass Burning in Southeast Asia on Tropospheric CO2 Concentration Over South China

AbstractThe field observations imply that the long‐range transport of carbon dioxide (CO2) emitted by biomass burning (BB) in Southeast Asia might impact the atmospheric CO2 in South China, while the transboundary path and the contributions of long‐range transport on atmospheric CO2 concentrations in South China remain poorly understood. In this study, a regional air quality model system (RAQMS) was developed by incorporating the atmospheric process of CO2 to investigate the impacts of BB in Southeast Asia on tropospheric CO2 concentration over South China in spring during 2009–2018. CO2 emissions from BB in Southeast Asia in spring varied greatly from 2009 to 2018, and high monthly mean emissions were concentrated in the west of Myanmar, the border between Myanmar, Thailand and Laos, the north of Laos, and Cambodia, with the maximum reaching 1.0 g m−2 hr−1. Higher monthly mean concentrations of near surface CO2 and tropospheric CO2 produced by BB were mainly distributed in the source regions of Southeast Asia and South China. The monthly mean tropospheric CO2 concentrations produced by BB in Southeast Asia were higher in March 2010, 2014, and 2015, which were obviously related to the interannual variation of BB emission, and affected by the atmospheric circulation as well. The contribution of BB emission in Southeast Asia to the net change of tropospheric CO2 concentration in South China presented a belt distribution from the southwest to the northeast, with a domain average of 5.7%–38.6% over South China in March 2009–2018.

Analysis and Assessment of Gaseous Pollutants along High Traffic Roads (NH 948) in Coimbatore City, India

&lt;p&gt;The growing Urbanization, Industrialization, Institutional, and IT sector development contribute to the exponential growth of motorized road transportation increasing the composition of harmful gaseous pollutants in ambient air. So, it is necessary to analyze and quantify the concentration of pollutants such as CO, NOx, SOx, and PM10 (for calculating the Air Quality Index) in ambient air at traffic signal zones in National Highway 948 across Coimbatore city and to model its dispersion using Quantum GIS. Using a Respirable Dust Sampler, the ambient air samples are collected at various locations based on heavy traffic signals zones during the month of December 2022 – March 2023.Quantified data are compared with National Ambient Air Quality Standards (NAAQS) to know about air quality, i.e., Air Quality Index. The dispersion rate in terms of concentration of CO, NOx, and SOx in the sampling locations of National Highway 948 revealed that; In comparison to other sampling months, the mean NOx concentration was higher in December at SL1 (78 µg/m³).The mean concentration value of SOx was high at SL2 (57 µg/m³) in the month of February 2023, and the mean concentration of CO is relatively high at SL1 (1.93 mg/m3) in NH 948.Sampling Locations such as SL1, SL5, SL7, and SL11 fall under the category of Poor compared to other sampling locations because of improper alignment of roadway, Traffic congestion, Liberty, and Violation of Traffic rules, Lack of vehicular maintenance, and End life vehicles. The lack of implementation of environmental regulations contributes to the bad air quality in most Indian cities.&lt;/p&gt;&#x0D;

Development of surface observation-based two-step emissions adjustment and its application on CO, NOx, and SO2 emissions in China and South Korea

It is challenging to estimate local emission conditions of a downwind area solely based on concentrations in the downwind area. This is because air pollutants that have a long residence time in the atmosphere can be transported over long distances and influence air quality in downwind areas. In this study, a Two-step Emissions Adjustment (TEA) approach was developed to adjust downwind emissions of target air pollutants with surface observations, considering their long-range transported emission impacts from upwind areas calculated from air quality simulations. Using the TEA approach, CO, NOx, and SO2 emissions were adjusted in China and South Korea between 2016 and 2021 based on existing bottom-up emissions inventories. Simulations with the adjusted emissions showed that the 6-year average normalized mean biases of the monthly mean concentrations of CO, NOx, and SO2 improved to 0.3 %, −2 %, and 2 %, respectively, in China, and to 5 %, 7 %, and 4 %, respectively, in South Korea. When analyzing the emission trends, it was estimated that the annual emissions of CO, NOx, and SO2 in China decreased at a rate of 7.2 %, 4.5 %, and 10.6 % per year, respectively. The decrease rate of emissions for each of these pollutants was similar to that of ambient concentrations. When considering upwind emission impacts in the emissions adjustment, CO emissions increased by 1.3 %/year in South Korea, despite CO concentrations in the country decreasing during the study period. During the study period, NOx and SO2 emissions in South Korea decreased by 3.9 % and 0.5 %/year, respectively. Moreover, the TEA approach can account for drastic short-term emission changes (e.g., social distancing due to COVID-19). Therefore, the TEA approach can be used to adjust emissions and improve reproducibility of concentrations of air pollutants suitable for health studies for areas where upwind emission impacts are significant.

Gasoline Generators and their Effects on Air Quality of Some Selected Business Centers in Tertiary Institutions in Rivers State

This study considered gasoline generators and their effects on air quality of some selected business centers in tertiary institutions in Rivers State. Air quality monitor was positioned 1.5m above the floor to determine the concentration levels of CO, CO2 and O2. The measurements were done on a daily for a period of three weeks. At FCE (T), Omoku, the mean concentration values of CO for Business and Institution’s generators were 109.2ppm and 62.3ppm; CO2 283.6ppm and 27.4ppm and O2 185.8% and 192.1% respectively. At IAUE, Port-Harcourt, CO for Business and Institution’s generators had mean concentration values of 144.7ppm and 89.6ppm; CO2 210.9 ppm and 188.8ppm, and for O2, 225.4% and 239.2% respectively. Similarly, for RSU, Port-Harcourt, the mean concentration of CO for Business and Institution’s generators were 144.8ppm and 84.5ppm; CO2 171.1ppm and 124.ppm; and for O2, 196.8% and 164.3%. respectively. CEAP, Port-Harcourt, CO had mean concentration values of 215.3ppm and light 92.2ppm, CO2 226.2ppm and 109.2ppm, whileO2 mean concentration values of 120.1% and 198.2% respectively. The concentration levels of CO, CO2 for business generators were much higher compared to when Institutions’ generators were used. The mean values of CO concentrations for the selected institutions for the period under study were higher than OSHA permissible exposure limit (PEL) of 50ppm (55mg/m3), NIOSH recommended exposure limit (REL) of 35ppm (40 mg/m3) and ACGIH threshold limit value (TLV) of 25ppm (28.6mg/m3), while that of CO2 concentration levels were less than OSHA’s established permissible limit of 5000ppm, and American Conference of Governmental Industrial Hygienists(ACGIH) threshold limit value (TLV) of 25ppm. It was also observed that as the concentrations of CO and CO2 increase, the O2 levels also decrease. It is therefore, very important to state that tertiary institutions’ managements in Nigeria should consider the provision of regular power supply on

Metal and metalloid bioaccumulation in dried red seaweed Hypnea musciformis and health risk assessment for consumers

This study measured 22 metal and metalloid concentrations in Hypnea musciformis from the Bakkhali River estuary and Saint Martin's Island, Bangladesh and determined their potential impact on consumption. Student t-tests showed a significant variation in metal concentrations between the two sampling sites (p < 0.05). Mean concentrations of Co (2.49 ± 0.05 mg/kg), Fe (793.29 ± 11.76 mg/kg), Mn (368.72 ± 4.87 mg/kg), Pb (3.82 ± 0.02 mg/kg), V (11.23 ± 0.20 mg/kg) and Zn (16.60 ± 0.28 mg/kg) were higher in samples collected from the Bakkhali River estuary compared to Saint Martin's Island, while mean concentrations of Ca (484.18 ± 4.68 mg/kg), Cd (2.44 ± 0.03 mg/kg), Mg (2112.70 ± 17.80 mg/kg), Mo (1.57 ± 0.06 mg/kg), Sr (2377.57 ± 29.98 mg/kg), and Ti (258.27 ± 4.62 mg/kg) were higher in samples collected from Saint Martin's Island. Eight heavy metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) were used to assess potential health risks for adults, but no potential health risk was detected (HQ value>1). This study reveals positive Se-HBV for H. musciformis collected from both sampling sites, indicating no potential risks involved with Hg toxicity.

Impact of Air Pollution on Respiratory Diseases in Typical Industrial City in the North China Plain

Air pollution can lead to the elevated incidence of various respiratory diseases, seriously endangering the health of urban residents. To better comprehend the association between urban air pollution and respiratory disease incidence, this study focused on Xinxiang City, a typical industrial city in the North China Plain, as the research object. By analyzing monthly air pollution index concentrations from 2018 to 2021 and confirmed cases of respiratory diseases, and incorporating meteorological factors as reference points, we conducted a correlation analysis between disease data and pollutant concentrations. We then constructed a Poisson regression model to obtain maximum likelihood estimates, which were used to predict the quantitative relationship between the incidence of respiratory diseases and air pollution indicators. The results showed that an increase of 1 μg/m³ in the average mass concentration of PM2.5, PM10, NO2, and SO2 in ambient air was associated with an elevated incidence of respiratory diseases by 0.2–1.4%, 0.7–1.6%, 3.7–8.2%, and 0.5–2.3%, respectively; meanwhile, a monthly mean mass concentration of CO increased by 1 mg/m³ led to a rise in pulmonary tuberculosis incidence by 2.9%. Additionally, based on health risk data following exposure to air pollution in Xinxiang City, it was confirmed that the impact of respiratory diseases as measured by the air quality composite index was more applicable than the single pollution index. Furthermore, there was a significant association between air pollution and the incidence of respiratory diseases.

Spatio-temporal variations and socio-economic drivers of air pollution: Evidence from 332 Chinese prefecture-level cities

Air pollution is the result of a complex interaction between natural and anthropogenic environmental conditions. Recently, what's the mutual correlation between air pollutants, and how the monthly socio-economic indicators influence air pollution at the prefecture-level cities are still lack of discussion. Based on monthly air pollutants concentrations and socio-economic indicators from January 2015 to September 2020, this study systematically explored the spatial-temporal characteristics of China's air pollutants and its socio-economic drivers. Results showed that annual mean concentrations of CO, NO2, SO2, PM10 and PM2.5 fell substantially from 2015 to 2020, decreasing by 37%, 27%, 63%, 39% and 40%, respectively, whereas O3 changed slightly. Summertime O3 and NO2 pollution in North China Plain, and wintertime air pollution in China remained the seriously polluted. PMs concentrations were significantly positively correlated with SO2, CO and NO2 concentrations. The increases in GDP per capita aggravated NO2 and PMs pollution in southeast coastal areas in spring and winter. The air pollution in North China Plain were severer in spring and winter induced by the monthly retail sales of social consumer goods. In the Fenwei Plain, the growing electricity consumption per GDP contributed to O3 and PM10 mitigation in summer and autumn. It is worth noting that the improvement of socio-economic level and energy consumption level showed a trend of exacerbating CO, NO2, and O3 pollution from 2015 to 2020. The comprehensive monthly analysis provides theoretical support for fine-scale monitoring and feasible control strategy formulating for achieving China's sustainable development.

Experimental study for comparison of thermal comfort and air age between two combined ventilation systems with chilled ceiling considering occupant density

AbstractDue to the global spread of diseases and epidemics, the need to maintain a clean indoor atmosphere has received increasing attention in recent years. Therefore, there will be a need to clearly estimate and define the areas that affect human exposure to pollutants, taking into account the occupied density, which is the primary importance of this research. The capacity of the chilled ceiling combined with mixing ventilation and personal ventilation systems has been studied and compared to the chilled ceiling with mixing ventilation in terms of mean air age, temperature distribution, CO2 concentration, and thermal efficiency, with the best flow rate of the proposed system considering the occupied density in a thermally insulated office room experimentally in the climate of Iraq (Hilla, a hot and dry climate). Twelve tests were performed for four different cooling loads with cooled ceilings (0%, 0.25%, 50%, and 80%), at a constant supply air flow rate with two PV airflow modifiers for three cases. As the cooling load treated by a chilled ceiling increased, the average air temperature increased with height in all cases. The lowest values of average air age appeared in the occupied area in the case of a chilled ceiling with mixing ventilation. This study shows that the chilled ceiling combined with a mixing ventilation and personal ventilation system with a flow rate of 7.5 L/s provides thermal comfort and higher air quality in the occupied area. based on the values of air exchange efficiency and occupants’ air exchange efficiency. As a result, a flow rate of 7.5 L/s is the best option for protecting occupants from direct pollution in the breathing zone and in the surrounding microclimate, because the lower the ventilation rate, the less air is changed for occupants.

Application of Hollow Fiber Membrane for the Separation of Carbon Dioxide from Atmospheric Air and Assessment of Its Distribution Pattern in a Greenhouse

Research on carbon management is fueled by the growing concern over rising carbon dioxide (CO2) levels in the atmospheric air and its possible impacts on the climate. In this study, we proposed a method of CO2 separation from atmospheric air. This study aimed to investigate the effects of CO2 enrichment on the air temperature inside a greenhouse using a hollow fiber (HF) membrane system. The experiment was conducted over a period of 30 days in two experimental conditions: 15 days without CO2 enrichment (WCS) and 15 days with CO2 enrichment (CS). Results showed that the mean CO2 concentration and air temperature were highest inside the greenhouse during the CS period, with values of 1120 ppm and 37.42 °C, respectively. Regression analysis revealed a positive correlation between CO2 concentration and temperature during the CS period (R2 = 0.628). The HF membrane system was found to be effective in increasing both the CO2 concentration and air temperature inside the greenhouse. However, the system also has limitations, including the cost, maintenance, and suitability for all types of crops. Further experiments are needed to address these limitations and determine the optimal CO2 concentration for different kinds of crops growing in greenhouses.

Remote sensing of dissolved CO2 concentrations in meso-eutrophic lakes using Sentinel-3 imagery

Satellite observation can significantly reduce the uncertainties in CO2 emission estimations compared to insufficient field data. However, big challenges remain in developing remote sensing-based models for mapping concentrations of dissolved carbon dioxide (cCO2) in lakes at regional or global scales. We developed a cCO2 estimation model using Sentinel-3-derived lake environmental variables and near-synchronous field cCO2 data from 16 lakes in the middle and lower reaches of the Yangtze and Huai River (ML_YHR) basins in Eastern China (N = 248). Stepwise quadratic polynomial regressions of several combinations of chlorophyll-a (Chl-a), water temperature (Tw), Secchi disk depth (ZSD), and photosynthetic active radiation (PAR)-related variables were tested and validated to select the best approach. The final model showed high performance in calibration and validation (R2 > 0.72, RMSE < 6.35 μmol L−1, MAPE < 30.31%). The model sensitivity analysis, based on Monte Carlo simulations, showed the model's estimated bias as <25% based on uncertainties of all input variables. Spatial and temporal dynamics of dissolved CO2 concentrations in 113 lakes (≥ 10 km2) in the ML_YHR basins were mapped from 2016 to 2021 using the Sentinel-3 data. The result showed that CO2 concentrations were low in the summer and autumn but high in the winter and spring with dramatic variations (e.g., mean coefficient of variation: 52.59%). The annual mean CO2 concentrations of lakes revealed that about 28% of the lakes acted as weak atmospheric CO2 sinks (14.96 ± 1.13 μmol L−1) while the rest were sources (19.22 ± 2.02 μmol L−1), compared with a mean concentration of CO2 atmospheric equilibrium (16.29 μmol L−1). CO2 concentrations decreased with increasing eutrophication and decreasing lake size (p < 0.05). This study advances current knowledge about CO2 emissions from emerging meso-eutrophic lakes and shows how satellite remote sensing can expand the spatiotemporal coverage of lake CO2.

Study on ventilation issues in urban nursery facilities: Long-term field survey in Yokohama, Japan

In many urban nursery facilities in Japan, daily ventilation behavior is restricted, and poor indoor air quality has been an issue of concern. However, the lack of specific common standards for indoor environments, including ventilation in nursery facilities, has left the issue unresolved in Japan. The purpose of this study is to clarify ventilation issues at nursery facilities in urban areas and indicate future measures. To this end, indoor air quality was analyzed using data from intermittent measurements taken between 2014 and 2022 at 21 nursery facilities in Yokohama City. As a result, the nursery facilities were classified into three categories based on nursery teachers’ ventilation behavior: “window-ventilation type,” “mechanical-ventilation type,” and “combined-ventilation type.” There was a significant difference (p-value &lt;0.001) in the mean CO2 concentration between the window-ventilation type and the mechanical-ventilation type, and between the window-ventilation type and the combined-ventilation type, confirming the difference indoor air quality due to the difference in ventilation behavior. It was clear that the mechanical-ventilation type and combined-ventilation type had significantly lower compliance rates with the minimum ventilation rate required by the Japanese Building Standard Law (20 m3/h), which buildings must have at a minimum.

GREENBOX Technology II - Comparison of Environmental Conditions, Productivity, and Water Consumption With Greenhouse Operation

Highlights Increasing population, demand, and urbanization have increased food security pressures. We compared GREENBOX with a greenhouse for urban crop production. GREENBOX and greenhouse provided the required environmental conditions and comparable biomass output year-round. GREENBOX performance is comparable to a greenhouse for urban crop production but with more advantages. Abstract. The Yang Laboratory at the University of Connecticut has developed the GREENBOX technology for growing fresh produce in urban areas to meet the increasing demand for sustainable and local food production. Previous studies have shown that GREENBOX units can provide the desired environmental conditions to sustain crop production in midlatitude urban warehouse environments. This study was conducted to compare the environmental conditions, productivity, and water consumption for growing lettuce between GREENBOX and a conventional greenhouse that has been widely applied for crop production. Two modular GREENBOX units, equipped with LED lighting, hydroponic growing platform, and climate controls, were located in a high ceiling headhouse of a greenhouse complex to mimic warehouse conditions. We used bays in a nearby greenhouse that was glass glazed, equipped with supplemental lighting, and fully controlled by an Argus Titan control system for comparison purposes. Forty-eight (48) heads of Butterhead Rex lettuce (Lactuca sativa) were grown over four 30-day cycles in spring, summer, fall, and winter in the GREENBOX units and the greenhouse bays, respectively, at the University of Connecticut, Storrs, Connecticut, United States. Environmental variables, including light, temperature, relative humidity, and carbon dioxide concentration, were measured at a frequency of every minute. Biomass data of wet weight, dry weight, total leaf area, and lettuce head area were collected using destructive and non-destructive methods every three days. The water consumption rate was logged using a lysimeter. We derived the Daily Light Integral (DLI), Leaf Area Index (LAI), Specific Leaf Area (SLA), productivity, and water consumed per lettuce head, per unit wet weight, and per unit dry weight from the measurements. Results were analyzed using descriptive statistics and ANOVA. The DLI values in the GREENBOX units were significantly higher than the recommended minimum DLI by over 20 mol/m2.d in the GREENBOX units and over 10 mol/m2.d in the greenhouse bays. The range of the daily temperature variation is only a few degrees in the GREENBOX units, while in the greenhouse bays was over 20°C. The average daily temperature in both growing locations fell within the optimal range of 17-29°C for lettuce. The relative humidity inside both growing locations fell primarily within the optimal range of 40%-60%. The mean CO2 concentrations inside both growing locations were slightly lower than the ambient concentration of 350 ppm. Measured parameters such as LAI, SLA, and productivity followed similar patterns, slightly different amongst seasons and higher in warmer seasons. ANOVA revealed a slightly (statistically insignificant) higher level of productivity in the GREENBOX units over the greenhouse bays (p=0.16), with higher values during the warmer seasons (p=0.72 in spring and summer). GREENBOX used 1.83-2.69 L of water per lettuce head, while the greenhouse bays used 1.69-3.84 L of water per lettuce head year-round. The water use was consistently lower in the GREENBOX units. We found that the GREENBOX units and greenhouse bays provided comparable environmental conditions, biomass output, and water consumption. Those variables, however, were more consistent in the GREENBOX units. GREENBOX environment was less affected by outside weather and, therefore, exhibited reduced fluctuations. The GREENBOX is advantageous over the greenhouse as it does not require arable or open land for intercepting sunlight and can be operated in available urban buildings such as warehouses. Keywords: GREENBOX, Greenhouse, Lettuce, Productivity, Water use.

An Assessment of Seasonal Variation of Carbon Emission and Carbon Sequestration in Rural Areas of Belagavi District, Karnataka

Introduction: Carbon emission cause climate change by trapping heat and they also contribute to respiratory disease from smog and air pollution. Therefore, reducing carbon emission is important because it mitigates the effects of global climate change, improves public health and maintains biodiversity. In carbon sequestration process atmospheric carbon is taken up by trees, grasses and plants through photosynthesis.&#x0D; Aim: Analyse the carbon emissions and estimate the carbon sequestration.&#x0D; Methodology: The study was conducted at Golihalli and Bidi village of Belagavi district, Karnataka in India to measure the carbon emission level through Air Quality Monitor and CO meter for one year. The carbon sequestration was assessed by non-destructive method.&#x0D; Results: An annual mean concentration of CO2 in Golihalli village was 924.33 ppm while in Bidi village 929.9 ppm and also the mean concentration of CO was 25.7 ppm in Golihalli village whereas 25.8 ppm in Bidi village. The mean concentration of PM2.5 was 57.8 μm3 and PM10 was 107.5 μm3 in Golihalli village however PM2.5 was 57.9 μm3 and PM10 was 108 μm3 in Bidi village. During the observation period, the maximum carbon emission concentration was measured in summer season and the minimum in rainy season. The largest value of carbon sequestration was seen in Tamarindus indica (530.22 gm) in Bidi village and Azdirachta indica (519.77 gm) in Golihalli village.&#x0D; Conclusion: The carbon emission concentration was exceeding the safe level in both villages because of rural people’s day-today activities and vehicular pollution. The trees with higher age and DBH have more carbon sequestration which could help in mitigate the effects of carbon emitted in the village.

Air pollutant dispersion in street canyons based on an outdoor scale model and machine learning

Air quality often deteriorates in street canyons owing to poor ventilation and increased emissions. In this study, the factors controlling air pollutant dispersion in street canyons were examined using outdoor scale models and machine learning. CO2 concentrations were measured at different heights for different ratios of building height (H) to street width (W) (H/W = 1, 2, 3). The results showed that when H/W increased from 1 to 2 and from 2 to 3, the mean CO2 concentration at a height of 0.25H (0.75H) in the street canyon increased by approximately 1 and 2 (0.5 and 1.5, respectively) times, respectively. An eXtreme Gradient Boosting (XGBoost) regression model for CO2 concentration was developed using machine learning based on different street canyon morphologies, monitoring locations, and meteorological conditions. Cross-validation demonstrated that the XGBoost model performed well on the test set, with an R2 value of 0.95. The SHapley Additive explanation (SHAP) values calculated for all samples showed that the five features that contributed most to the CO2 concentration were H/W, d (along-canyon position of the sensor), T (air temperature), W/2 (cross-canyon position of the sensor), and b_ws (atmospheric environmental background wind speed), with contributions of 34.1%, 19.1%, 12.1%, 10.5%, and 10.0%, respectively.