Environmental Pollution Monitoring Research Articles

The Ground-Level Particulate Matter Concentration Estimation Based on the New Generation of FengYun Geostationary Meteorological Satellite

The new-generation FengYun geostationary meteorological satellite has a high spatial and temporal resolution, which is advantageous in environmental assessments and air pollution monitoring. This study researched the ground-level particulate matter concentration estimation, based on satellite-observed radiations. The radiation of ground-level particulate matter is separate from the apparent radiation observed by satellites. The positive correlation between PM2.5 and PM10 is also considered to improve the accuracy of inversion results and the interpretability of the estimation model. Then, PM2.5 and PM10 concentrations were estimated synchronously every 5 min in mainland China based on FY-4A satellite directly observed radiations. The validation results showed that the improved model estimated results were close to the ground site measured results, with a high determination coefficient (R2) (0.89 for PM2.5, and 0.90 for PM10), and a small Root Mean Squared Error (RMSE) (4.69 μg/m3 for PM2.5 concentrations, and 13.77 μg/m3 for PM10 concentrations). The estimation model presented a good performance in PM2.5 and PM10 concentrations during typical haze and dust storm cases, indicating that it is applicable in different weather conditions and regions.

Environmental Applications of Zeolites: Hydrophobic Sn-BEA as a Selective Gas Sensor for Exhaust Fumes

Environmental monitoring of pollutants, such as NOx and COx, which can be facilitated by a range of gas sensors, is of considerable fundamental and practical importance. This work has been focused on the synthesis and evaluation of zeolite β with tin (Sn-BEA) and dealuminated β (DeAl-BEA) zeolites. The zeolite samples have been extensively investigated by IR, UV-VIS and NMR spectroscopy, XRD, TGA, and N2 adsorption-desorption. The prepared Sn-BEA sample is characterised by the submicron particle size, an almost defect-free structure, and high hydrophobicity. Sensors containing selective microporous layers based on Sn-BEA and DeAl-BEA zeolites have been prepared and extensively tested. Both the Sn-BEA and DeAl-BEA zeolites have been deposited in thin films and evaluated as gas sensors for CO, CO2, NO, and NO2 in the presence of water vapour at room temperature. The Sn-BEA zeolite-based sensor showed high selectivity towards NO2, while the DeAl-BEA is selective towards CO2 and NO2.

Development and Implementation of Automated Qualification Processes for the Identification of Pollutants in an Aquatic Environment from High-Resolution Mass Spectrometric Nontarget Screening Data

Environmental pollution monitoring represents a major challenge due to the growing presence of a large and diverse number of potential contaminants. In complement to target analysis, nontarget analysis, via liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS), is increasingly used to provide a more comprehensive characterization of pollution. The challenge associated with this type of analysis is particularly related to the data treatment for substance identification. One of the main limitations is that all data must be manually reviewed, which is tedious and time-consuming. Machine learning algorithms aim to reproduce human behavior, and their capabilities were therefore evaluated to automatically identify substances in suspect screening approaches. After selecting the relevant features produced from LC/HRMS, seven different machine learning models were evaluated for each of the three different databases, which resulted in the selection of logistic regression (LR) and random forest (RF)-based algorithms. An interface was built to rank the identified substances and to assess the performance of the developed models. The LR model provided the best results when retention times were available. The developed LR and RF models were determined complementarily, particularly when no retention times were available. However, limitations were noticed when using a database containing different HRMS technologies.

Mesoporous molecularly imprinted nanoparticles with peptide mimics for the detection of phenolic compounds

Immobilized enzymes outperform free enzymes in many properties and are widely used in environmental monitoring, engineering applications, food and medical fields. Based on the developed immobilization techniques, the search for immobilization with wider applicability, lower cost and more stable enzyme properties is of significant importance. In this study, we reported a molecular imprinting strategy for immobilizing peptide mimics of DhHP-6 on mesoporous materials. The DhHP-6 molecularly imprinted polymer (MIP) showed much higher adsorption capacity than raw mesoporous silica toward DhHP-6. The DhHP-6 peptide mimics was immobilized on the surface of mesoporous silica for the fast detection of phenolic compounds, a widely spread pollutant with highly toxic and difficult in degradation. Immobilized enzyme of DhHP-6-MIP exhibited higher peroxidase activity, better stability, and recyclability than free peptide. Notably, DhHP-6-MIP showed excellent linearity for the detection of the two phenols with detection limits of 0.28 μM and 0.25 μM, respectively. In combination with the spectral analysis and PCA method, DhHP-6-MIP provided better discrimination between the six phenolic compounds (phenol, catechol, resorcinol, hydroquinone, 2-chlorophenol, 2, 4-dichlorophenol). Our study showed that immobilization of peptide mimics by the molecular imprinting strategy using mesoporous silica as carriers was a simple and effective approach. The DhHP-6-MIP has great potentiality for the monitoring and degradation of environmental pollutants.

Phenothiazine-based multifunctional fluorescent probe for one-site rapid detection of hydrazine in cells, soil, water samples and test strip

Hydrazine is widely used as a wide range of industrial chemical reagents. Because of its toxicity and explosiveness, it poses a serious threat to human health and ecological security. Therefore, it is of great significance to develop a real-time tracing method for hydrazine. Here, a novel turn-on fluorescent probe SXNU-1 for the detection of hydrazine was synthesized based on phenothiazine. SXNU-1 showed excellent selectivity toward hydrazine over various competitive species. Vinyl group with cyano and ethylacetate groups in SXNU-1 could react with hydrazine to form Schiff's base, showing bright green fluorescence. The response mechanism was verified by theoretical calculation, 1H NMR titration and HRMS. In addition, SXNU-1 can determine hydrazine in soil, water samples and test strip. Because SXNU-1 has good cell membrane permeability, it can monitor different concentrations of hydrazine in HeLa cells. Therefore, we believe that SXNU-1 has great potential in the analysis and monitoring of environmental pollutants.

Nanotechnology for Remediating Current Environmental Problems

Nanotechnology can play important role in the field of environmental restoration and science. Environmental pollution has become one of the major problems of developing as well as developed countries at present time. Unchecked exploitation of resources, rapid industrialization, urbanization as well as excessive agricultural activities to meet the demands of the ever increasing population are the major cause for contamination of the land, water and atmosphere at all levels. Increasing pollution is not only resulting in the destruction of biodiversity, but it also causes degradation of human health. Recently, nanotechnology has emerged as an answer to these problems having significant role in environmental monitoring, pollution prevention and remediation methods. Nanotechnology has many advantages to improve present environmental technologies and help to create new technologies in comparison to the conventional one. Present article explores the role of different nanoparticles available for environmental remediation purposes and pollution monitoring.

A Nanosensor-Based Prototype Development for Heavy Metal Detection: A Combined Spectroscopic and Theoretical Study

With the advent of technology, nanosensors have proved to be an important tool, which provide a sustainable solution for environmental pollution monitoring. Herein, we report a spectroscopic detection of lead (Pb); one of the toxic heavy metal pollutants with the help of citrate functionalized gold nanoparticles (Au NPs) followed by development of a low-cost prototype device. Self-aggregation of citrate functionalized Au NPs in presence of Pb has been observed spectroscopically. The longitudinal mode of surface plasmon resonance of Au NPs increases as the Pb concentration increases, and consequently, a new peak in the red region of the EM spectrum emerges, which is a clear indication of self-aggregation of NPs. We have used quasi-static approximation based numerical modeling to determine the percentage of aggregation of the AU NPs, which in turn, could be used to determine the amount of Pb <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions present in the solution. These key findings have been utilized for the development of low-cost prototype for monitoring Pb pollution in the environment.

Photoresponsive oxidase-like phosphorescent carbon dots in colorimetric Hg2+ detection

Developing novel photoresponsive oxidase mimics is highly useful for environmental pollution monitoring and biological sensing. Herein, long-life room-temperature phosphorescent nitrogen-doped carbon quantum dots (P-NCDs) were synthesized from triethylenetetramine hexaacetic acid via a simple one-step hydrothermal method. The P-NCDs showed high photoresponsive oxidase-like activity. On this basis, a P-NCD-based photostimulated colorimetric sensing system was developed and used to detect Hg2+ in environmental and biological samples. P-NCDs under 365 nm UV lamp irradiation converted dissolved oxygen, via triplet excited state (T1) exciton transfer, to singlet oxygen (1O2), which then oxidized 3,3′,5,5′-tetramethylbenzidine (TMB), leading to a color changing reaction. Cysteine can suppress the catalysis of P-NCDs, and its specific complexation with Hg2+ can recover the oxidation activity of P-NCDs. Hence, efficient colorimetric Hg2+ detection with a linear range of 0.01–14 μM and a detection limit of 3.1 nM was achieved by detecting the color change of TMB. The feasibility of this strategy was validated through real sample analysis. Our study broadens the application scope of phosphorescent nanomaterials into colorimetric sensing.

Effect of glyphosate and ciprofloxacin exposure on enteric bacteria of tadpoles

The high load of agrochemicals and antibiotics present in agricultural aquatic environments represents a risk for wildlife. Since enteric bacteria, which play a key role in the physiological functioning of their hosts, are sensitive to a wide variety of pollutants, their study allows to evaluate the health of organisms. This study aimed to evaluate the effects of commercial formulations of a glyphosate-based herbicide (GBH) and the antibiotic ciprofloxacin (CIP), individually and in mixture, on the bacterial diversity of the intestinal content of common toad (Rhinella arenarum) tadpoles. The diversity of cultivable fast-growing bacteria with low nutritional requirements was evaluated using classic microbiological tests and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry identification. Bacterial diversity varied among treatments. Taxa diversity increased in the GBH-treated group but decreased in the CIP-treated group. Remarkably, Yersinia spp. and Proteus spp. were only found in the GBH-treated group. The prevalence of Klebsiella spp. and Pseudomonas spp. decreased in the intestinal microbiota of the GBH-CIP-treated group. To our knowledge, this is the first report on the alteration of cultivable enteric bacteria of autochthonous tadpoles due to two pollutants of emerging concern. Our results demonstrate that R. arenarum tadpoles can be used as non-conventional model organisms for environmental pollution monitoring. Our preliminary findings would contribute to understanding how the presence of GBH and CIP in freshwaters may represent a threat to wildlife and human health by causing enteric dysbiosis of part of the bacterial community.

A water stable and highly fluorescent Zn(II) based metal-organic framework for fast detection of Hg2+, CrVI, and antibiotics.

The development of luminescent metal-organic frameworks for effective sensing and monitoring of environmental pollutants is of great significance for human health and environmental protection. In this work, a novel water-stable ZnII-based luminescent coordination polymer, namely {[Zn(BBDF)(ATP)]·2DMF·3H2O}n ((BBDF = 2,7-bis(1H-benzimidazol-1-yl)-9,9-dimethyl-9H-fluorene) and H2ATP = 2-aminoterephthalic acid), was designed and obtained using the mixed-ligand method. Structural analysis indicated that 1 presents a two-fold interpenetrated two-dimensional layer structure with one dimensional (1D) channels along the a axis. Intriguingly, the uncoordinated -NH2 group was danged onto the pore walls of 1. Remarkably, compound 1 shows good aqueous stability at different pH values of 3-13 and exhibits a fluorescence turn-off sensing behavior for Hg2+, Cr2O72-, CrO42-, and antibiotics (NFZ, NFT) in aqueous solution with high selectivity and sensitivity. The limits of detection (LOD) are 0.12 μM (Hg2+), 0.17 μM (Cr2O72-), 0.21 μM (CrO42-), 0.098 μM (NFZ), and 0.14 μM (NFT). The luminescence quenching mechanism analysis by experiment and theoretical calculation revealed that the competitive absorption and the photoinduced electron transfer process are largely responsible for the sensing of the two antibiotics, while the weak interaction contributes to the selective luminescence quenching for Hg2+.

Electrochemical environmental pollutant detection enabled by waste tangerine peel-derived biochar

Nitrite is widely utilized in food and agricultural fields. Excessive nitrite causes great harm to ecosystems and human health, rendering it one of environmental pollutants. In this work, tangerine peel, as a common agricultural waste in daily life, is considered as a sustainable, renewable and low-cost carbon precursor. Tangerine peel waste has been re-utilized to prepare biochar of iron oxide/nitrogen-doped carbon nanocomposite in constructing electrochemical sensor for nitrite determination. Two electrochemical techniques of linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were practiced for quantifying nitrite. The biochar of iron oxide/nitrogen-doped carbon nanocomposite displayed satisfactory sensing performance in different real environmental samples of soil, spinach and mustard. Agricultural waste to value-added product is becoming increasingly significant. Considering that a lot of tangerine peel is discarded as waste in daily life, the present strategy will be promising to transform a common agricultural waste into value-added product, thus having profound significance in contributing to both the smart farming, pollution alleviation and environmental pollutant monitoring.

Study and Realization of Environmental Health Diagnosis by Using Nanomaterial Based Fiber Optic Sensor–A Review

In these days, the significance of fiber optic sensors has exceptionally increased due to technological advances in modern society. Nowadays, researchers are attracted toward the development of a sensor that possesses the integration of both fiber optic sensors and nanocomposite thin film to improve the sensor’s performance. Thin-film nanomaterial based optical fiber sensors have great potential applications, namely, gas sensing, chemical sensing, biomolecules, food plant, industrial hazards, safety issues, drug monitoring, and heavy metal detections. There are various techniques, namely, evanescent field absorption spectroscopy, fiber Bragg grating (FBG), long-period grating (LPG), ringdown spectroscopy, surface plasmon resonance (SPR), Mach–Zehnder interferometer (MZI) techniques, and so on, which are used for the development of fiber optic sensors that are majorly emphasized in the current article. Numerous scientific researchers have demonstrated that functionalized fiber optic sensors are found more beneficial in terms of improvement of the sensing performance, such as sensitivity, repeatability, response time, specificity, recovery time, and repeatability. Henceforth, in this review article, we have focused on these requisite sensing parameters in detail. Furthermore, to keep human beings healthy, it is our responsibility to develop a sensor that can monitor the optimum toxic concentrations accurately. Thus, the monitoring of industrial environmental pollutants, such as NH3, ethylenediamine, alcohol, and acetone, is immensely important to save human lives on Earth. In the report, all the details of the target analytes, such as optimum concentrations, adverse effects on human beings, and monitoring techniques, are discussed.

Nanoscale designing of metal organic framework moieties as efficient tools for environmental decontamination.

Environmental pollutants, being a major and detrimental component of the ecological imbalance, need to be controlled. Serious health issues can get intensified due to contaminants present in the air, water, and soil. Accurate and rapid monitoring of environmental pollutants is imperative for the detoxification of the environment and hence living beings. Metal-organic frameworks (MOFs) are a class of porous and highly diverse adsorbent materials with tunable surface area and diverse functionality. Similarly, the conversion of MOFs into nanoscale regime leads to the formation of nanometal-organic frameworks (NMOFs) with increased selectivity, sensitivity, detection ability, and portability. The present review majorly focuses on a variety of synthetic methods including the ex situ and in situ synthesis of MOF nanocomposites and direct synthesis of NMOFs. Furthermore, a variety of applications such as nanoabsorbent, nanocatalysts, and nanosensors for different dyes, antibiotics, toxic ions, gases, pesticides, etc., are described along with illustrations. An initiative is depicted hereby using nanostructures of MOFs to decontaminate hazardous environmental toxicants.

Review of the state of air pollution by energy objects in Ukraine

Objective information about the state of air pollution is the basis for implementing measures to ensure conditions for the safe living of the population and improve the environmental pollution monitoring network. The purpose of the work is to study the impact of energy facilities (enterprises consuming different types of fuels) on atmospheric air pollution and its spatial and temporal distribution in cities and regions of Ukraine. The relevance of the work is confirmed by the fact that Ukraine, according to the World Health Organization, has the highest mortality rate from diseases caused by polluted air. The article considers general approaches to the functioning of the air pollution monitoring system in Ukraine and the features of the formation of the local air pollution index. The article discusses the most common pollutants generated at energy-intensive enterprises in Ukraine, in particular benzo(a)pyrene (C20H12), sulfur dioxide (SO2), dust, carbon monoxide (CO), nitrogen oxides (NxOy), hydrogen sulfide (H2S), carbon disulfide (CS2), hydrogen fluoride (HF), ammonia (NH3), phenol (C6H6O) and others. Statistical information about emissions of pollutants (CO2, SO2, NO2, CO, PM10, PM2,5, PAHs, Zn, Pb, Cu, Cr, Ni, As) into the air from stationary sources of pollution for the period 1990-2018 was analyzed and visualized. The dynamics of chemical air pollution in different cities and regions of Ukraine are analyzed in detail. For some cities (Kyiv, Dnipro, Odesa, Kharkiv), energy-intensive enterprises and types of pollutants emitted into the air have been identified. It is shown that among the most polluted cities are Mariupol, Dnipro, Odesa, Kamianske, Kyiv, Kryvyi Rih, Lutsk, Lysychansk, Mykolaiv, Sloviansk, Kramatorsk, Rubizhne, Lviv, Zaporizhzhia, Lysychansk, Kherson, Kremenchuk, and among the most polluting regions are Donetsk, Dnipropetrovsk, Ivano-Frankivsk, Zaporizhzhya, Lviv, Vinnytsia, Kyiv, Cherkasy, Poltava. These regions need priority implementation of modern air pollution monitoring systems. Keywords: air pollution, chemical pollution, stationary sources, energy objects, pollution dynamics, maximum permissible concentration

A Real-Time Web Information System Based on A Global Positioning System for Monitoring Environmental Pollution

This research will discuss monitoring pollution in waterways in real time based on GPS. A website-based information system is an essential factor for information media, not only database-based but can be communicated with GPS. GPS is a satellite system that can determine the point of an area with Longitude and Latitude parameters. The Global Positioning System is one of the parameters used in this study. Longitude and Latitude are the primary keys to getting the point in a particular area or point. In research, this is the location used in sensor or environmental pollution monitoring. In this paper, we try to review the projects carried out and perform analysis, management, and governance on the server and local host. The program is made by developing the FrontEnd and BackEnd sides. Development can be done on Desktop-based programming and then extended to Mobile by manipulating and modifying programs using Javascript, JSON, and other building scripts for better performance and suitable for deployment on various platforms such as Mobile-based. This system is very efficient in determining various parameters, for example, the environmental pollution factor. From testing, the GPS data is not perfect, all data can be sent, but the accuracy of GPS data can reach 96%. This is due to data errors during uplinking and downlinking data.

Pithecellobium dulce Leaf-Derived Carbon Dots for 4-Nitrophenol and Cr(VI) Detection

Luminescent carbon dots (CDs) synthesized from Pithecellobium dulce (P. Dulce) leaves, in a simple, single-step carbonization procedure, were used as optical nanosensors. TEM revealed the crystalline nature of the CDs with the average dimension of 20 nm with a quantum yield of 24%. In addition to carbon, the X-ray photoelectron spectroscopy shows the presence of oxygen and nitrogen. The FTIR spectra and Zeta potential were used for additional characterization of the nanoprobes. Among the contaminants and heavy metals, the proposed nanoprobes were found to be selective towards 4-nitrophenol (4-NP) and Cr(VI), respectively. The emission response of CDs towards 4-NP solution not only reveals the high sensitivity of the CDs (Limit of detection (LOD) of 14 nM) but also demonstrates a color change (light to dark yellow) that is attributed to spontaneous deprotonation detectable with the naked eye. The selectivity of CDs towards Cr(VI) (LOD 0.9 nM) was also tested in the presence of other metals. The quenching mechanism has been attributed to the inner filter effect for both analytes. The observed low detection limits in river and tap water opens up the possible applicability of the proposed nanoprobes as optical sensors in environmental pollution monitoring.

Identification of Environmental Pollutants in Construction Site Monitoring Using Association Rule Mining and Ontology-Based Reasoning

Pollutants from construction activities of building projects can have serious negative impacts on the natural environment and human health. Carrying out monitoring of environmental pollutants during the construction period can effectively mitigate environmental problems caused by construction activities and achieve sustainable development of the construction industry. However, the current environmental monitoring method relying only on various sensors is relatively singlar which is unable to cope with a complex on-site environment We propose a mechanism for environmental pollutants identification combining association rule mining and ontology-based reasoning and using random forest algorithm to improve the accuracy of identification. Firstly, the ontology model of environmental pollutants monitoring indicator in the construction site is built in order to integrate and share the relative knowledge. Secondly, the improved Apriori algorithm with added subjective and objective constraints is used for association rule mining among environmental pollutants monitoring indicators, and the random forest algorithm is applied to further filter the strong association rules. Finally, the ontology database and rule database are loaded into a Jena reasoning machine for inference to establish an identification mechanism of environmental pollutants. The results of running on a real estate development project in Jiangning District, Nanjing, prove that this identification mechanism can effectively tap the potential knowledge in the field of environmental pollutants monitoring, explore the relationship between environmental pollutants monitoring indicators and then overcome the shortcomings of traditional monitoring methods that only rely on sensors to provide new ideas and methods for making intelligent decisions on environmental pollutants in a construction site.

The Biological Monitoring as a Source of Information on Environmental Pollution with Heavy Metals

Abstract The influence of environmental pollution on living organisms has been known for a long time, but it was not until the second half of the twentieth century that methodical studies on the influence of anthropopressure on changes in ecosystems began. Living organisms began to be used as biological indicators of environmental pollution. Cyclical and quantitative studies of pollutant concentrations in bioaccumulators have become the basis of modern biological monitoring (biomonitoring) of environmental pollution. Biomonitoring studies are carried out with the passive method (passive biomonitoring), in which living organisms occurring in their natural environment are analysed, and with active methods (active biomonitoring), in which, for example, plants living in the environment with low pollution are transferred and displayed in more polluted ecosystems e.g. heavy metals. The analysis of trace elements, including heavy metals accumulated in algae, mosses and lichens used in biological monitoring provides a lot of information on, among others concentration and origin of pollutants and the directions of their spread. Biomonitoring is used to assess the level of contamination of selected ecosystems, as well as the impact of individual emitters on the environment. An important element in determining the concentrations of trace elements in biological material used in biomonitoring is the proper planning of the experiment, taking into account, among others: methods of collecting or exposing samples, selection of analytical methods and methods of evaluation and interpretation of results. The aim of the presented long-term research, conducted by the Research Team of the Institute of Biology of the University of Opole, was to show that analytical techniques using biota samples can provide reliable data on the past, present and future state of the environment. However, it should be remembered that in order for the results of biomonitoring studies to be reliable and comparable, the applied research methodologies should be consistent and repeatable. In the presented research, Palmaria palmata and Spirogyra sp. algae, Pleurozium schreberi mosses, Hypogymnia physodes and bark of deciduous trees were used. In samples of biological material by the method of atomic absorption spectrometry, the concentrations of heavy metals, including Ni, Cu, Zn, Cd and Pb, were determined. On the basis of the conducted research, it was unequivocally stated that the biomonitoring methods are a good complement to the classic methods of environmental quality assessment. The analysis of the elements accumulated in the biological material provides us with information about the quality of the examined ecosystems, the introduced pollutants and their potential sources. This information allows for the introduction of effective measures to improve the quality of the environment.

A GPS Based Unmanned Drone Technology for Detecting and Analyzing Air Pollutants

Air pollution is now becoming a global issue because it directly affects human health, by creating cancer, respiratory and cardiac diseases, and the earth's ecosystem, by causing climate change and depletion of ozone layers. The rapid expansion of civilization and industrialization, leading to hazardous emissions from automobiles, chemical industries, and fossil fuel burning, plays a significant role in air and atmospheric pollution. Unmanned aerial systems and the internet of things-based sensing devices have provided new impetus for automatic air pollution monitoring and analysis. In this paper, an automatic indoor and outdoor air quality monitoring system has been developed using an unmanned aerial vehicle: a drone. The proposed device is constructed from an ultra-strength DJI F450 frame, various gas sensors, a particulate matter detector, and a camera to detect and distinguish air pollution data. The precision and sensitivity of the proposed device have been evaluated by collecting air emissions data from two places in Dhaka, Bangladesh. The drone has been navigated in Uttara and Bashundhara areas to measure the amount of CO, CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> , O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , SO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> , NOx, and dust in indoor and outdoor environments. We obtained higher air pollution concentrations in Uttara than in Bashundhara, as it is an area with more industries and construction sites. The proposed system composed of an uncrewed aerial device and low-cost gas monitoring sensors is expected to create new possibilities in environmental and air pollution monitoring.

Zinc oxide tetrapod sponges for environmental pollutant monitoring and degradation

Environmental monitoring systems enable the collection of information about the various environmental parameters, pollution levels, and the presence of environmental hazards affecting human and marine life. Highly sensitive, stable, and low-power-consuming sensors are vital for such operations. Nanomaterials with different surface morphologies can play a vital role in multiple applications, such as gas sensors, photocatalysts, erosion monitoring, or fine dust sensor. Zinc oxide (ZnO) tetrapod, in particular, shows 3D morphologies that exhibit exciting properties, making them applicable in several device engineering. This work provides a simple yet high-throughput single-step synthesis of ZnO tetrapod with different arm sizes using the flame transport method at various growth conditions. The physicochemical and structural properties have been deeply investigated to shed light on the formation of these 3D structures. The detailed mechanism of the ZnO tetrapod as a gas monitoring material and a photocatalyst has been presented in detail. The sponge-based ZnO gas sensor can selectively sense NO2 gas with a limit of detection (LOD) value of 8.56 ppb. In addition, ZnO tetrapods samples exhibit high photocatalytic activity toward methylene blue and methyl orange degradation under UV illumination. The reaction rate constants of 3.6 (2)·10−4 s−1 and 1.7 (1)·10−4 s−1 are determined for the photocatalytic decomposition of methylene blue and methyl orange, respectively. The results suggest that ZnO tetrapod-based sponges can be a promising material for building next-generation pollution monitoring and degradation systems.