NH3 Levels Research Articles

Room-temperature highly sensitive and selective NH3 gas sensor using vertically aligned WS2 nanosheets

Here, we report the room temperature (35 °C) NH3 gas sensor device made from WS2 nanosheets obtained via a facile and low-cost probe sonication method. The gas-sensing properties of devices made from these nanosheets were examined for various analytes such as ammonia, ethanol, methanol, formaldehyde, acetone, chloroform, and benzene. The fabricated gas sensor is selective towards NH3 and exhibits excellent sensitivity, faster response, and recovery time in comparison to previously reported values. The device can detect NH3 down to 5 ppm, much below the maximum allowed workspace NH3 level (20 ppm), and have a sensing response of the order of 112% with a response and recovery time of 54 s and 66 s, respectively. On the other hand, a sensor made from nanostructures has a bit longer recovery time than a device made from nanosheets. This was attributed to the fact that NH3 molecules adsorbed on the surface site and those trapped in between WS2 layers may have different adsorption energies . In the latter case, desorption becomes difficult and may give rise to slower recovery as noticed. Further, stiffened Raman modes upon exposure to NH3 reveal strong electron-phonon interaction between NH3 and the WS2 channel. The present work highlights the potential use of scaled two-dimensional nanosheets in sensing devices and particularly when used with inter-digitized electrodes, may offer enhanced performance.

S- and N-Co-Doped TiO2-Coated Al2O3 Hollow Fiber Membrane for Photocatalytic Degradation of Gaseous Ammonia.

This study successfully prepared and tested sulfur- and nitrogen-co-doped TiO2-coated α-Al2O3 (S,N-doped TiO2/Al2O3) hollow fiber (HF) membranes for efficient photocatalytic degradation of gaseous ammonia (NH3). Thiourea was used as a sulfur- and nitrogen-doping source to produce a S,N-doped TiO2 photocatalyst powder. For comparative purposes, undoped TiO2 powder was also synthesized. Through the application of a phase-inversion technique combined with high-temperature sintering, hollow fibers composed of α-Al2O3 were developed. Undoped TiO2 and S,N-doped TiO2 photocatalyst powders were coated on the α-Al2O3 HF surface to obtain undoped TiO2/Al2O3 and S,N-doped TiO2/Al2O3 HF membranes, respectively. All prepared samples were characterized using XRD, TEM, XPS, UV-Vis, SEM, BET, FT-IR, and EDS. S and N dopants were confirmed using XPS and UV-Vis spectra. The crystal phase of the undoped TiO2 and S,N-doped TiO2 photocatalysts was a pure anatase phase. A portable air purifier photocatalytic filter device was developed and tested for the first time to decrease the amount of indoor NH3 pollution under the limits of the lachrymatory threshold. The device, which was made up of 36 S,N-doped TiO2/Al2O3 HF membranes, took only 15-20 min to reduce the level of NH3 in a test chamber from 50 ppm to around 5 ppm, confirming the remarkable performance regarding the photocatalytic degradation of gaseous NH3.

Assessment of air quality, health status and lung function of workers from selected poultry management systems in Ogun State, Nigeria

Background/ObjectivesThis study assessed the air quality, health status and lung function of workers from intensive poultry production systems in selected areas of Ogun State. MethodsAir samples were monitored monthly between November 2017 and April 2018 from six pens in three selected poultry zones of Ogun State. The air pollutants (CO2, CH4, NO2, NH3, H2S, SO2, PM2.5) and the microclimatic parameters around the poultry pens were determined. Copies of structured questionnaires were administered to assess the impacts of air pollutants on the health status of the poultry workers. Lung function parameters [Forced Expiratory Volume in 1 s (FEV1), Forced Vital Capacity (FVC), FEV1/FVC and Peak Expiratory Flow Rate (PEFR)] were measured to assess the pulmonary health of the poultry workers and the control group. ResultsThe levels of NH3, PM2.5, CO2 and CH4 were higher than the permissible standards while NO2, H2S and SO2 were below the permissible limits of the World Health Organization. Regression analysis between pollutants and microclimatic parameters showed that relative humidity and windspeed had negative effects on PM2.5, NO2, H2S and SO2. FEV1/FVC measured for poultry workers was 86.84 ± 18.32% with 10.0% having obstructive lung function, while the control group had 98.82 ± 1.52% with 100% normal lung function pattern. The predicted PEFR for poultry workers was significantly lower at 61.12 ± 27.85% with 13.3% having severe airway restrictions, while the predicted PEFR for the control group was significantly higher at 88.41 ± 21.76% with no severe airway narrowing. ConclusionsThis study established that air quality around the poultry operations affected the workers’ health.

Exploring use of a commercial passive sampler in a closed static chamber to measure ammonia volatilization

Studies have indicated that up to 47% of total N fertilizer applied in flooded rice fields may be lost to the atmosphere through NH3 volatilization. The volatilized NH3 represents monetary loss and contributes to increase in formation of PM2.5 in the atmosphere, eutrophication in surface water, and degrades water and soil quality. The NH3 is also a precursor to N2O formation. Thus, it is important to monitor NH3 volatilization from fertilized and flooded rice fields. Commercially available samplers offer ease of transportation and installation, and thus, may be considered as NH3 absorbents for the static chamber method. Hence, the objective of this study is to investigate the use of a commercially available NH3 sampler/absorbent (i.e., Ogawa® passive sampler) for implementation in a static chamber. In this study, forty closed static chambers were used to study two factors (i.e., trapping methods, exposure duration) arranged in a Randomized Complete Block Design. The three trapping methods are standard boric acid solution, Ogawa® passive sampler with acid-coated pads and exposed coated pads without casing. The exposure durations are 1 and 4 h. Results suggest that different levels of absorbed NH3 was obtained for each of the trapping methods. Highest level of NH3 was trapped by the standard boric acid solution, followed by the exposed acid-coated pads without casing, and finally acid-coated pads with protective casing, given the same exposure duration. The differences in absorbed NH3 under same conditions does not warrant direct comparison across the different trapping methods. Any three trapping methods can be used for conducting studies to compare multi-treatments using the static chamber method, provided the same trapping method is applied for all chambers.

Impacts of Covid-19 Lockdown on Concentration Levels of Traffic-Related Air Pollutants in Ibadan -a West African City

Trends and sources of air pollution at twenty-five traffic Intersections (TIs) before and during covid-19 lockdown were investigated in Ibadan, Nigeria. The relationships among climatic parameters, vehicular counts and ten air pollutants which includes particulate matter (PM1, PM2.5, PM10 & Total Suspended Particles-TSP) and gaseous pollutants (CO, NO2, SO2, NH3, total volatile organic compounds-TVOCs, and ground level O3) measured simultaneously at TIs were analysed. Results indicated significant decrease in mean concentrations of all pollutants studied except NO2 with 212% increase during the study period. Concentrations of gaseous pollutants CO, SO2, NH3, TVOCs and ground level O3 reduced by 7.92%, 24.80%, 1.58%, 44.08% and 4.28%, respectively while particulates concentrations of PM1, PM2.5, PM10 and TSP concentrations decreased by 49.64%, 60.79%, 81.21% and 84.17%, respectively during lockdown. An integrated source apportionment approach using Pearson’s correlation, Airflow backward trajectories arriving in the study area and Principal component analysis (PCA) identified vehicular emission as the primary source of studied air pollutants at TIs before and during lockdown in Ibadan. Emission from residences, roadside fuel combustion and local air transport of pollutants from nearby upwind areas with industries and farming activities were identified as secondary sources of air pollution affecting the study area.

Carbon Dioxide, Oxygen, and Ammonia Levels in Mouse and Rat Disposable IVC Removed from Mechanical Ventilation.

Maintenance of an appropriate microenvironment for rodents used in research is of paramount importance because changes in environmental parameters such as O₂ and humidity can influence animal health and welfare and potentially alter research results. Here we evaluated the microenvironment of mouse and rat disposable cages after removal from mechanical ventilation in order to guide recommendations for their use. Cages with sealed IVC lids, unsealed lids (partially ajar), and lids without the exhaust filter (for rats) or static lids (for mice) were removed from the ventilated rack and were thereafter monitored CO₂, O₂, and NH₃ levels. For mice, effects were investigated under both standard (set point of 72°F/22°C) and thermoneutral (set point of 82°F/28°C) temperatures. When IVC with sealed lids and group-housed C57BL/6J male mice were removed from ventilation under standard temperatures, CO₂ started at 6,600 ± 265 ppm at 0 h and rose to 42,500 ± 7,263 ppm at 1 h, with mice showing a visibly elevated respiratory rate in 1 of the 3 cages; CO₂ stabilized at 26,150 ± 3,323 ppm at 8 h. In contrast, CO₂ levels in cages with single mice were stable after 1 h (1,350 ± 409 ppm at 0 h, 9,367 ± 802 ppm at 1 h, and 8,333 ± 1,115 ppm at 8 h). Findings were similar at thermoneutral temperatures: sealed group-housed mice cages started at 3,617 ± 475 ppm at 0 h and rose to 39,333 ± at 5,058 ppm at 1 h, whereas sealed cages with 1 mouse started at 1,117 ± 247 ppm at 0 h and were 7,500 ± 1,997 ppm at 8 h. IVC with sealed lids and pair-housed Crl:CD(SD) female rats rose to 48,000 ± 2,828 ppm CO₂ and over 70% humidity within 1 h. By 3 h, IVC with sealed lids and singly housed rats had 40,167 ± 5,132 ppm CO₂, and rats were displaying a visually elevated respiratory rate. O₂ levels had an inverse relationship with CO₂ levels. Removing the rat lid exhaust filter was not helpful. However, leaving the IVC lid ajar ameliorated the rise in CO₂ and fall in O₂ for both species. Therefore, IVC with sealed lids and group-housed mice should not be removed from ventilation more than 1 to 2 h; IVC containing pair- or singly-housed rats IVC should not be removed for more than 1 or 3 h, respectively. Whenever possible, such cages should be fitted with static lids, left partially ajar and monitored, or replaced on ventilation.

Improved neural network with least square support vector machine for wastewater treatment process

This research offers a unique interval by using the predicting approach for discharge indicators of water quality data such as biochemical oxygen demand (BOD) and ammonia nitrogen (NH3–N). This is considered one of the significant quality metrics in wastewater treatment plants for water quality management as well as surveillance. To begin, the effluent information for BOD/NH3–N and their supplementary parameters are gathered. Hence BOD and NH3 are considered major feature sources for estimating water pollutants. BOD is high then oxygen level is very low in the water due to pollutants or algae. Ammonia nitrogen is an organic waste component in water from sewage. The significant characteristics with good correlation levels of BOD and NH3–N are examined and identified using a grey correlation analysis method after certain basic data pre-processing procedures. The BOD/NH3–N effluent information of a water treatment plant is predicted using an upgraded feed-forward neural network with the least square support vector machine (FFNN-LSSVM) method. An optimization approach for an enhanced feed-forward neural network (IFFNN) is built by Machine Learning Algorithms. The IFFNN used regular influent water quality, influent rate of flow, and Wastewater performance monitoring and operational conditions as input parameters. For future prediction, input variables were previous different wastewater quality measurements. Lastly, the analysis shows that, when compared to other current algorithms, the proposed methodology can forecast wastewater quality of water with high accuracy in predicting BOD and NH3 levels, limited computation duration, mean error less than 10% and R2 is 90% proves better than existing techniques.

Amino Acids Supplied through the Autophagy/Endocytosis Pathway Promote Starch Synthesis in Physcomitrella Protonemal Cells.

The physiological implications of autophagy in plant cells have not been fully elucidated. Therefore, we investigated the consequences of autophagy in the moss Physcomitrella by measuring biochemical parameters (fresh and dry weights; starch, amino acid, carbohydrate, and NH3 content) in wild-type (WT) and autophagy-deficient atg5 Physcomitrella cells. We found higher starch levels and a higher net starch synthesis rate in WT cells than in atg5 cells cultured in a glucose-containing culture medium, whereas net starch degradation was similar in the two strains cultured in a glucose-deficient culture medium. Additionally, the treatment of cells with the autophagy inhibitor 3-methyladenine suppressed starch synthesis. Loading bovine serum albumin into atg5 cells through endocytosis, i.e., supplying proteins to vacuoles in the same way as through autophagy, accelerated starch synthesis, whereas loading glutamine through the plasma membrane had no such effect, suggesting that Physcomitrella cells distinguish between different amino acid supply pathways. After net starch synthesis, NH3 levels increased in WT cells, although the change in total amino acid content did not differ between WT and atg5 cells, indicating that autophagy-produced amino acids are oxidized rapidly. We conclude that autophagy promotes starch synthesis in Physcomitrella by supplying the energy obtained by oxidizing autophagy-produced amino acids.

Evaluation of Microalgal Bacterial Dynamics in Pig-Farming Biogas Digestate under Impacts of Light Intensity and Nutrient Using Physicochemical Parameters

Determination of the dynamics between microalgae and bacteria in pig farming biogas digestate is vital for a consistent and reliable application towards sustainable wastewater treatment and biofuel production. This study assesses the reliability of using physicochemical parameters as indicators for the rapid evaluation of microalgal bacterial dynamics in real digestate under impacts of light, nutrient loads, and N:P ratios. The relationship between variation profiles of nutrients, biomass and physicochemical properties in each experiment was analyzed. High light and high nutrient load enhanced biomass growth and nutrient removal rate. Ammonium addition (high N:P ratio) elevated NH3 level which inhibited the growth of microalgae, subsequently reducing the biomass growth and nutrient removal. Low N:P ratio triggered the accumulation of phosphorus and the growth of chlorophyll-a but exerted little influence on treatment. Variation profiles of dissolved oxygen, nutrient and biomass were highly consistent in every experiment allowing us to identify the shift from microalgal to bacterial predomination under unfavorable conditions including low light intensity and high N:P ratio. Strong linear correlation was also found between total nitrogen removal and electrical conductivity (R2 = 0.9754). The results show the great potential of rapid evaluation of microalgal bacterial dynamics for large scale system optimization and modelling.

A Room-Temperature Surface Acoustic Wave Ammonia Sensor Based on rGO/DPP2T-TT Composite Films.

Surface acoustic wave (SAW) sensors based on reduced graphene oxide/poly (diketopyrrolopyrrolethiophene-thieno [3,2-b]thiophene-thiophene) (rGO/DPP2T-TT) composite sensing films for the detection of ammonia were investigated at room temperature in this study. The rGO/DPP2T-TT composite films were deposited onto ST-X quartz SAW resonators by a drop-casting method. FESEM, EDS, and XRD characterizations showed that the rGO/DPP2T-TT composite film was successfully synthesized and exhibited numerous wrinkles and a rough structure, which are crucial for gas adsorption. The frequency response to 500–1400 ppb ammonia shown by the prepared SAW sensor coated with rGO/DPP2T-TT composite film increased linearly as the ammonia concentration increased. The sensor based on a rGO/DPP2T-TT composite film exhibited a positive frequency shift of 55 Hz/ppm, and its frequency response to 500 ppb ammonia was 35 Hz. The sensors thus show promising potential in detecting sub-ppm concentration levels of NH3 at room temperature, which opens up possibilities for applications in the noninvasive detection of NH3 in the breath. As a result, the rGO/DPP2T-TT composite sensor can be a good candidate for in situ medical diagnosis and indoor/outdoor environment monitoring.

Marked shifts in gut microbial structure and neurotransmitter metabolism in fresh inmates revealed a close link between gut microbiota and mental health: A case-controlled study

Background/ObjectiveThe gut microbiota plays a pivotal role in psychological health, but the mechanistic perspective between gut microbiome and mental health remains poorly understood MethodThe present case-controlled study recruited 30 unimprisoned subjects and 31 inmates that had been detained in jail for no more than a month. The mental health status, gut microbiota and blood NH3, H2S, 5-hydroxy trptamine and dopamine levels were measured. ResultsCompared with unimprisoned controls, the fresh inmates exhibited significantly higher scores on anxiety and depression. Both phylogenetic structure and functional genes of the gut microbiota markedly shifted in inmates. Inmates was more Bacteroides-dominated, while unimprisoned subjects were more Prevotella-dominated. Short-chain fatty acids (SCFAs)-producing genera were largely decreased in inmates and were negatively related to mental disorder scores, while Bacteroidetes and Proteobacteria were positive to anxiety and depression scores. Simultaneously, the inmates possessed reduced genes that participate in amino acids, carbohydrates and vitamin cofactors metabolism, but enriched genes that involved in the neurotransmitter-producing Shikimate pathway. Correlation analysis revealed that Anaerotruncus and Prevotella were negative to depression score, and Enterococcus was negative to anxiety score. ConclusionsOur results revealed potential link between gut microbiota and mental health, leading further support to the microbiota–gut–brain axis theory.

Ground-based measurements of atmospheric NH3 by Fourier transform infrared spectrometry at Hefei and comparisons with IASI data

Atmospheric ammonia (NH3) plays an important role in the formation of fine particulate matter, leading to severe environmental degradation and human health issues. In this work, ground-based Fourier transform infrared spectrometry (FTIR) observations are used to obtain the total columns of atmospheric NH3 at Hefei, China, from December 2016 to December 2020. After the presentation of the retrieval algorithm and uncertainty budget, we perform a spatio-temporal analysis of the dataset. Over the four years, NH3 columns have been increasing by 15.82% (2017–2018), 3.83% (2018–2019) and 3.68% (2019–2020). A clear seasonal cycle is observed, with the largest surface concentrations (12.93 ± 6.40 ppb) observed in June to August, and the lowest (4.08± 2.66 ppb) in November to January. The diurnal cycles of NH3 exhibit increased morning and afternoon concentrations. Interpretation of the diurnal cycles is difficult, however, the absence of a peak during rush hours, and the absence of correlation with CO and NO2 suggest that agriculture and not traffic is the main source of NH3 at Hefei. The polar plots of NH3 columns with wind and back trajectories of air masses calculated by the HYSPLIT model confirmed that agriculture was the dominant source of ammonia in four seasons, while urban anthropogenic emissions contributed to the high level of NH3 in summer over the Hefei site. We end this paper with a short validation exercise of NH3 columns retrieved from measurements of the IASI satellite data with the FTIR measurements over Hefei. Correlation coefficients (R) between the two datasets are 0.79 and 0.75 for IASI-A and IASI-B, with the slope of 0.96 and 1.10, respectively. The mean difference is −3.44 × 1015 and −3.96 × 1015 molec cm−2, with standard deviation of 7.16 × 1015 and 8.10 × 1015 molec cm−2, respectively. These results demonstrate the IASI and FTIR data, over Hefei, are in broad agreement.

Seasonal atmospheric characteristics in a swine finishing barn equipped with a continuous pit recirculation system using aerobically treated manure.

This study was conducted to determine the seasonal characteristics of odorous material emissions from a swine finishing barn equipped with a continuous pit recirculation system (CPRS) using aerobically treated manure. The CPRS consists of an aerobic manure treatment process and a pit recirculation system, where the solid fraction is separated and composted. The aerated liquid fraction (290.0%±21.0% per day of total stored pig slurry) is continuously recirculated to the top of the slurry in the pit. Four confinement pig barns in three piggery farms were used: two were equipped with CPRS, and the other two operated a slurry pit under the slatted floor across all seasons. The indoor, exhaust, and outside odor intensities were significantly lower in the CPRS group than in the control group (p<0.001). In the CPRS group, the odor intensity outside was significantly lower in the fall than in the other seasons (p = 0.015). In the indoor atmosphere, the temperature and CO2, NH3, and H2S contents of the CPRS group were significantly lower than those of the control group (p<0.05). In the CPRS group, indoor temperature did not significantly change in the spring, summer, and fall seasons and was significantly lower in the winter (p = 0.002). NH3, H2S, methyl mercaptan, dimethyl disulfide, trimethylamine, phenol, indole, and skatole levels were significantly lower in the CPRS group than in the control group (p<0.05). There were significant seasonal differences on the odorous material in both the control and CPRS groups (p<0.05), but the pattern was not clear across seasons. The CPRS can reduce the indoor temperature in the summer to a level similar to that in the spring and fall seasons. The CPRS with aerated liquid manure is expected to reduce and maintain malodorous emissions within acceptable limits in swine facilities.

Seasonal Aerosol Acidity, Liquid Water Content and Their Impact on Fine Urban Aerosol in SE Canada

This study explores the drivers of aerosol pH and their impact on the inorganic fraction and mass of aerosol in the S.E. Canadian urban environments of Hamilton and Toronto, Ontario. We find that inter-seasonal pH variability is mostly driven by temperature changes, which cause variations of up to one pH unit. Wintertime acidity is reduced, compared to summertime values. Because of this, the response of aerosol to precursors fundamentally changes between seasons, with a strong sensitivity of aerosol mass to levels of HNO3 in the wintertime. Liquid water content (LWC) fundamentally influences the aerosol sensitivity to NH3 and HNO3 levels. In the summertime, organic aerosol is mostly responsible for the LWC at Toronto, and ammonium sulfate for Hamilton; in the winter, LWC was mostly associated with ammonium nitrate at both sites. The combination of pH and LWC in the two sites also affects N dry deposition flux; NO3− fluxes were comparable between the two sites, but NH3 deposition flux at Toronto is almost twice what was seen in Hamilton; from November to March N deposition flux slows down leading to an accumulation of N as NO3− in the particle phase and an increase in PM2.5 levels. Given the higher aerosol pH in Toronto, aerosol masses at this site are more sensitive to the emission of HNO3 precursors compared to Hamilton. For both sites, NOx emissions should be better regulated to improve air quality during winter; this is specifically important for the Toronto site as it is thermodynamically more sensitive to the emissions of HNO3 precursors.

Quartz-enhanced photoacoustic NH3 sensor exploiting a large-prong-spacing quartz tuning fork and an optical fiber amplifier for biomedical applications

A sensor system for exhaled ammonia (NH3) monitoring exploiting quartz-enhanced photoacoustic spectroscopy (QEPAS) was demonstrated. An erbium-doped fiber amplifier (EDFA) with an operating frequency band targeting an NH3 absorption line falling at 1531.68 nm and capable to emit up to 3 W of optical power was employed. A custom T-shaped grooved QTF with prong spacing of 1 mm was designed and realized to allow a proper focusing of the high-power optical beam exiting the EDFA between the prongs. The performance of the realized sensor system was optimized in terms of spectrophone parameters, laser power and modulation current, resulting in a NH3 minimum detectable concentration of 14 ppb at 1 s averaging time, corresponding to a normalized noise equivalent absorption coefficient (NNEA) of 8.15 × 10−9 cm−1 W/√Hz. Continuous measurements of the NH3 level exhaled by 3 healthy volunteers was carried out to demonstrate the potentiality of the developed sensor for breath analysis applications.

Evaluation and association of laying hen performance, environmental conditions and gas concentrations in barn housing system

Various environmental, constructional, and human-related factors affect overall eggs production. The egg poultry production has been analysed in barn housing system depending on birds' life cycle time and environmental conditions (carbon dioxide concentration, outdoor and indoor temperature, indoor relative humidity). Within the present research study, the data provided by the Baltic poultry industry company has been analysed. Outside temperature, environmental conditions, carbon dioxide (CO2) and ammonia (NH3) concentrations were continuously monitored in two-storey tunnel-ventilated layer house from January to June 2021. CO2 and NH3 gas concentrations were higher during the winter (p < .05). The outdoor temperature during investigation was in range from −27 °C to +13 °C. The indoor temperature and CO2 concentration were higher on the 2nd storey (p < .05) and influenced by outdoor temperature. The relationships between CO2 gas concentrations and environmental conditions (indoor and outdoor temperature, indoor relative humidity) have been detected in the research. The indoor relative humidity tended to be negatively correlated with indoor temperature (rxy = −0.59) and positively correlated with CO2 concentration (r xy = 0.68, r xy = 0.54); the indoor temperature increased, then relative humidity and CO2 decreased. Results showed that the hen-day egg production and feed conversion ratio (FCR) depend on the hen age (p < .05) and temperature (p < .05), and not depend on the CO2 levels. If the CO2 and NH3 levels are in acceptable range, gases will not influence hen performance.

Robust Evidence of 14C, 13C, and 15N Analyses Indicating Fossil Fuel Sources for Total Carbon and Ammonium in Fine Aerosols in Seoul Megacity.

Carbon- and nitrogen-containing aerosols are ubiquitous in urban atmospheres and play important roles in air quality and climate change. We determined the 14C fraction modern (fM) and δ13C of total carbon (TC) and δ15N of NH4+ in the PM2.5 collected in Seoul megacity during April 2018 to December 2019. The seasonal mean δ13C values were similar to −25.1‰ ± 2.0‰ in warm and −24.2‰ ± 0.82‰ in cold seasons. Mean δ15N values were higher in warm (16.4‰ ± 2.8‰) than in cold seasons (4.0‰ ± 6.1‰), highlighting the temperature effects on atmospheric NH3 levels and phase-equilibrium isotopic exchange during the conversion of NH3 to NH4+. While 37% ± 10% of TC was apportioned to fossil-fuel sources on the basis of fM values, δ15N indicated a higher contribution of emissions from vehicle exhausts and electricity generating units (power-plant NH3 slip) to NH3: 60% ± 26% in warm season and 66% ± 22% in cold season, based on a Bayesian isotope-mixing model. The collective evidence of multiple isotope analysis reasonably supports the major contribution of fossil-fuel-combustion sources to NH4+, in conjunction with TC, and an increased contribution from vehicle emissions during the severe PM2.5 pollution episodes. These findings demonstrate the efficacy of a multiple-isotope approach in providing better insight into the major sources of PM2.5 in the urban atmosphere.

Deodorization of the off-gas from livestock manure aerobic composting tank using biotrickling filters and its mechanism

In this study, two biotrickling filters (BTFs) were fabricated to treat the off-gas produced during the aerobic composting of animal manure, namely: BTF-A (packed with volcanic rock) and BTF-B (packed with ceramsite). The results showed that the major contributors to the odor level of the off-gas were ammonia (NH3) and total volatile organic compounds (TVOCs). The removal efficiencies of BTF-B for NH3, TVOCs, and odor level (88.78 ± 5.03%, 70.25 ± 6.95% and 88.10 ± 13.21%, respectively) were superior to those of BTF-A. Partial nitrification was achieved in the circulating water with a pH of 7.0–8.2, dissolved oxygen (DO) content of 1–3 mg/L, and an average free ammonia (FA) content of 16.65 mg/L (without denitrification occurring). Ca. Nitrosoglobus was observed as the dominant ammonia-oxidizing bacteria in the BTF deodorization process. In addition, a deodorization mechanism based on Ca. Nitrosoglobus and Ralstonia sp. in the biofilm on packings was proposed.

Changes in physicochemical, heavy metals and air quality linked to spot Aplocheilus panchax along Mahanadi industrial belt of India under COVID-19-induced lockdowns.

Positive effects of COVID-19-induced lockdowns on environment are well documented although pre-planned experiments for such analyses and appearance of fish species are lacking. We hypothesize that spotting the fish Aplocheilus panchax along the industrial belt of Mahanadi River near Cuttack in a never seen manner could be due to the regenerated environment. Heavy metals, water and air qualities along with spotting A. panchax in up, mid and downstream of Mahanadi River near Jagatpur industrial basins were analysed during pre-(end of March 2020) and after 60 days of lockdowns (last week of May 2020). An overall 45, 61, 79, 100, 97 and 90% reduction of Fe, Cu, Ni, Cd, Pb and Zn was recorded in the studied area after lockdowns, respectively. Similarly, dissolved oxygen and pH were elevated by 26 and 7%, respectively. Water temperature, conductivity and total dissolved solute levels were reduced by 7, 46 and 15%, respectively, which were again elevated during post-lockdowns during 2021 as observed from the Landsat-8 OLI satellite data. Air NO2, SO2, NH3, PM2.5, PM10 and CO levels were alleviated by 58.75, 80.33, 72.22, 76.28, 77.33 and 80.15%, respectively. Finally, for the first time, about 12 A. panchax fish per 100 m shore line in the area were spotted. The observed lockdown-induced environmental healing at the studied area could contribute to the appearance of A. panchax in the study site and therefore a stringent environmental audit is suggested during post-COVID-19 periods to make the regenerated environmental status long lasting in such habitats.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10653-022-01247-3.

A Wearable Respiration Sensor for Real-Time Monitoring of Chronic Kidney Disease.

Human respiration is accompanied with abundant physiological and pathological information, such as the change in ammonia (NH3) content, which is related to chronic kidney disease (CKD); hence, monitoring the breathing behavior helps in health assessment and illness prediction. In this work, a wearable respiration sensor based on CeO2@polyaniline (CeO2@PANI) nanocomposites that underwent a hydrogen plasma treatment is developed. The results unambiguously show that the response of the corresponding nanocomposites is significantly enhanced from 165 to 670% to 100 ppm NH3 compared to the counterpart that did not undergo hydrogen plasma treatment and even reaches 24% to 50 ppb NH3, suggesting its fascinating capability of detecting the trace level of NH3 in human breathing. The superior response for NH3 is ascribed to the stable oxygen vacancies produced by the hydrogen plasma treatment. Furthermore, the clinical tests for patients with uremia suggest that the as-designed sensor has potential applications in clinical monitoring for CKD. Herein, this work offers a new strategy to obtain respiration sensors with high performance and provides a feasible approach for health evaluation and disease monitoring of patients with CKD.