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Assessing air quality's impact on human health involves monitoring pollutant concentrations such as NO2, O3, CO, SO2, and particulate matter. While high-income countries rely on expensive reference instruments, low-income nations face technological limitations. This study explores the potential of low-cost scientific devices as a viable solution for these regions. The research focuses on evaluating the reliability of low-cost NO2 sensors and consistency across five identical sensors. Calibration tests in controlled settings reveal a linear model with high coefficients of determination, contrasting with lower coefficients observed during field tests. Variability in intercepts and slopes is evident across time and campaign contexts. Time series analysis using low-cost NO2 sensors showed that many of the tall peaks atop a fluctuating baseline correlates with peaks identified by reference instruments. Additionally, NO gas sensors are also able to identify pollution peaks in monitoring campaigns. Therefore, such affordable sensors provide valuable insights into pollutant concentration trends, offering indicative magnitude information. However, improving calibration and reliability of these sensors necessitates further research.

The study investigates methods to enhance the reliability of NO2 monitoring using low-cost electrochemical sensors to measure gaseous pollutants in air by addressing the impacts of temperature and relative humidity. The temperature within a plastic container was controlled using an internal mica heater, an external hot air blower, or cooling packs, while relative humidity was adjusted using glycerine solutions. Findings indicated that the auxiliary electrode signal is susceptible to temperature and moderately affected by relative humidity. In contrast, the working electrode signal is less affected by temperature and relative humidity; however, adjustments are still required to determine gas concentrations accurately. Tests involving on/off cycles showed that the auxiliary electrode signal experiences exponential decay before stabilizing, requiring the exclusion of initial readings during monitoring activities. Additionally, calibration experiments in zero air allowed the determination of the compensation factor nT across different temperatures and humidity levels. These results highlight the importance of compensating for temperature and humidity effects to improve the accuracy and reliability of NO2 measurements using low-cost electrochemical sensors. This refinement makes the calibration applicable across a broader range of environmental conditions. However, the experiments also show a lack of repeatability in the zero air calibration.

In developing nations, outdated technologies and sulfur-rich heavy fossil fuel usage are major contributors to air pollution, affecting urban air quality and public health. In addition, the limited resources hinder the adoption of advanced monitoring systems crucial for informed public health policies. This study addresses this challenge by introducing an affordable internet of things (IoT) monitoring system capable of tracking atmospheric pollutants and meteorological parameters. The IoT platform combines a Bresser 5-in-1 weather station with a previously developed air quality monitoring device equipped with Alphasense gas sensors. Utilizing MQTT, Node-RED, InfluxDB, and Grafana, a Raspberry Pi collects, processes, and visualizes the data it receives from the measuring device by LoRa. To validate system performance, a 15-day field campaign was conducted in Santa Clara, Cuba, using a Libelium Smart Environment Pro as a reference. The system, with a development cost several times lower than Libelium and measuring a greater number of variables, provided reliable data to address air quality issues and support health-related decision making, overcoming resource and budget constraints. The results showed that the IoT architecture has the capacity to process measurements in tropical conditions. The meteorological data provide deeper insights into events of poorer air quality.

This contribution shows the possibilities of applying a low-cost, multi-purpose data logger built around an Arduino Mega 2560 single-board computer. Most projects use this kind of hardware to develop single-purpose data loggers. In this work, a data logger with a more general hardware and software architecture was built to perform measurement campaigns in very different domains. The wide applicability of this data logger was demonstrated with short-term monitoring campaigns in relation to outdoor air quality, human activity in an office, motion of a journey on a bike, and exhaust gas monitoring of a diesel generator. In addition, an assessment process and corresponding evaluation framework are proposed to assess the credibility of low-cost scientific devices built in-house. The experiences acquired during the development of the system and the short measurement campaigns were used as inputs in the assessment process. The assessment showed that the system scores positively on most product-related targets. However, unexpected events affect the assessment over the longer term. This makes the development of low-cost scientific devices harder than expected. To assure stability and long-term performance of this type of design, continuous evaluation and regular engineering corrections are needed throughout longer testing periods.

In the Western world, the SO2 concentration in ambient air dropped to low levels, but some emission sources (e.g., merchant ships) and some regions (e.g., low-income countries) still emit substantial amounts of SO2. At those locations, SO2 monitoring is critical. However, low-income countries do not have much access to expensive reference instruments. Low-cost gas sensors might be an alternative, but it is unclear how reliable such measurements are. To evaluate the performance of the low-cost alternative, the same SO2 gas sensor has been subjected to three different calibration methods: (1) low-cost calibration performed in the tropical climate of Cuba; (2) high-end calibration performed in Belgium; (3) a field calibration at an air quality measuring station in Belgium. The first two methods showed similar trends, suggesting that the gas sensor can be calibrated with a low-cost method. The field calibration was hampered by the low SO2 concentrations. For the monitoring campaign in Cienfuegos, Cuba, the low-cost SO2 sensor calibrated by the low-cost method appeared to be sufficiently reliable. The reliability of the sensor increases with the increase in SO2 concentration, so it can be used in Cuba instead of Belgium.

The purpose of this study was to evaluate the chemical, phasic and calorimetric evaluation of a pozzolanic material obtained by electric arc-assisted aluminothermy using cupola slag to provide criteria on its pozzolanic nature. Chemical characterization of cupola slag and synthesized pozzolanic material (MPS) was performed by using analytical methods such as volatilization gravimetry, complex formation volumetry, UV-VIS spectrophotometry, atomic absorption spectrometry, and phase characterization using semi quantitative analysis by XRD. The pozzolanic character of cupola slag and MPS was evaluated by means of alkaline solubility tests and isothermal calorimetry in Ca(OH)2-Puzolana and Portland Cement (CP)-Pozzolan paste systems. Cupola slag does not contain more than 70% of SiO2, Al2O3 and Fe2O3 as indicated in NC TS 528: 2007 for its use as pozzolan and has 60 % amorphism, while the MPS complies with the provisions of the standard and presents a 30 % amorphism. The highest values of the Si and Al contents in the cupola slag respect to MPS and the zeolite studied are associated with the predominance of a non-periodic distribution of these chemical elements in the amorphous domains. Higher pozzolanic reactivity of the MPS respect to cupola slag obtained by isothermal Ca(OH)2-Pozolana and CP-Pozzolan calorimetry is attributed to a combination of amorphous character with the increasing of reactive phases result from chemical and phase modifications by using aluminothermy in an electric arc furnace.

Low-cost sensors provide an affordable alternative to monitor environmental parameters with acceptable performance. There is a substantial amount of literature where low-cost sensors are compared with high-end reference measurements. However, not all organizations have access to such reference infrastructure. We propose low-cost calibration methods for temperature, relative humidity, and CO2 to allow them to collect their own reliable data. These methods are based on simple techniques and procedures that allow temperature calibration to be achieved in the range of 0 to 50 °C, relative humidity from 0 to 90%, and CO2 between 0 and 1100 ppm. The materials used to create the calibration setups can be purchased online, at hardware stores, and in pharmacies. The reliability of the calibration methods was evaluated using several indicators, such as the airtightness of the calibration box, similarity with the factory calibration, similarity with the reference, similarity between different sensors, replicability of the calibration method, and the similarity with a golden standard. In addition, the results of the low-cost calibration methods were compared with the more advanced calibration methods. A short measurement campaign in the city of Santa Clara, Cuba, demonstrated that such calibrations transform in-house developed monitoring systems into valid low-cost scientific instruments for decision-making. This work creates opportunities for institutions and researchers hosted in low- and mid-income countries to build and validate their own equipment to reliably solve local problems.

La evaluación de la calidad del aire urge en los momentos actuales con el propósito de preservar la salud de los humanos, este caso hace referencia a las emisiones del dióxido de azufre (SO2) por las 64 fuentes fijas del municipio de Caibarién, provincia de Villa Clara y su influencia en la ciudad, en el año 2018. El objetivo general fue evaluar la calidad del aire para SO2 a partir de las emisiones a la atmósfera producidas por estas fuentes. Se utilizó el método de cálculo basado en el factor de emisión para determinar la tasa de los contaminantes de ambas fuentes y la modelación de la dispersión del contaminante para evaluar la calidad del aire. Los principales resultados fueron, el 69% de las fuentes fijas están bien ubicadas y emitieron el 1% del total, el 26% están parcialmente bien ubicadas y expulsaron el 96% y el 5% están mal ubicadas y emitieron el 3%. Las áreas con deterioro de la calidad del aire en la ciudad de Caibarién se ubican a sotavento de las fuentes fijas mal ubicadas, principalmente las tenerías, con categoría de ¨Mala¨ y ¨Deficiente¨ en 24 horas. Se proponen acciones que contribuyen a reducir el consumo de combustible, elevar la eficiencia energética, minimizar las emisiones y favorecer el transporte y dispersión del contaminante, influyendo positivamente en la elevación de la calidad del aire en las zonas afectas.

En este trabajo se muestra el inventario de emisiones atmosféricas de las 306 fuentes fijas distribuidas en los sietes municipios costeros de la provincia de Villa Clara en el año 2018. El objetivo general fue cuantificar las emisiones del PM10 a la atmósfera producidas por estas fuentes fijas. Se utilizó el método de cálculo basado en el factor de emisión para determinar la tasa del contaminante por fuentes. Los principales resultados fueron, actualizar el inventario de emisiones de las fuentes fijas en esta zona del territorio provincial, desglosado por municipios, Oaces y de acuerdo a la clasificación de estas fuentes teniendo en cuenta el impacto sobre la calidad del aire. Se logró determinar que el 80% de las fuentes fijas están bien ubicadas y emiten el 2% del total de este contaminante, el 17% están parcialmente bien ubicadas y emiten el 96% y por último el 3% están mal ubicadas y emiten el 2% de la carga. La emisión total del PM10 fue de 2 191,5 t/año, representando el 75% del total provincial, de ello las fuentes fijas bien ubicadas emitieron 42,7 t/año, las parcialmente bien ubicadas 2 105,8 t/año y las mal ubicadas 43 t/año. Estos resultados proporcionan la información necesaria e imprescindible para las propuestas de acciones que contribuyan a reducir emisiones, minimizar episodios críticos de contaminación atmosférica y realizar la modelación de la dispersión del contaminante y su evaluación.

El presente trabajo manifiesta la evaluación de la calidad del aire para los Óxidos de Nitrógeno (NOX) a partir de las emisiones del inventario de las45fuentes fijas y el flujo automotriz por la vía principal, en el municipio de Santo Domingo, provincia de Villa Clara, en el año 2017. El objetivo general fue evaluar la calidad del aire para los NOx a partir de las emisiones a la atmósfera producidas por estas fuentes.Se utilizó el método de cálculo basado en el factor de emisión para determinar la tasa de los contaminantes de ambas fuentes y la modelación de la dispersión del contaminante para evaluar la calidad del aire.Losprincipales resultados fueron,el 82% de las fuentes fijas están bien ubicadas y emitieron el 7% del total, el 18% están parcialmente bien ubicadas y expulsaron el 91% ylas fuentes móviles emitieron el 2%.Las áreas con deterioro de la calidad del aire en la ciudad de Santo Domingo fueron las aledañas a la vía principal por donde circuló el transporte automotriz, alcanzando una categoría de Deficiente en 24 horas y Mala en una hora (mayor flujo vehicular). Las emisiones de las fuentes fijas parcialmente bien ubicadas pueden influir en la calidad del aire sobre los asentamientos poblacionales fuera de la ciudad, en zonas cercanas a sus orígenes.

Esta investigación muestra el inventario de emisiones atmosféricas de las 38 fuentes fijas y el flujo automotriz por la vía principal, en el municipio de Ranchuelo, provincia de Villa Clara, en el año 2017. El objetivo general fue cuantificarlas emisiones a la atmósfera producidas por estas fuentes. Los contaminantes primarios estudiados fueron, el Dióxido de Azufre (SO2), Óxidos de Nitrógeno (NOX), Monóxido de Carbono (CO). Se utilizó el método de cálculo basado en el factor de emisión para determinar la tasa de los contaminantes de ambas fuentes. Los principales resultados fueron, actualizar el inventario de emisiones de las fuentes fijas de las cuales, el 84% están bien ubicadas y emiten el 2% del total, el 11% están parcialmente bien ubicadas y emiten el 72% y por último el 5% están mal ubicadas y emiten el 14%. Las fuentes móviles emitieron el 12% del total. Las área con deterioro de la calidad del aire influenciado por estas emisiones corresponden a las aledañas a las fuentes fijas parcialmente bien ubicadas y mal ubicadas, además de alrededor de la vía principal por donde circula el transporte automotriz. La emisión de los NOx fue de 56,24 t/año, representando el 67% del total, en segundo lugar el SO2 con 14,94 t que constituye el 18% y por último el CO con 12,49 t que alcanza el 15%.Estos resultados facilitan las propuestas de acciones para reducir emisiones, además se crearon las bases para la modelación de la dispersión de los contaminantes y su evaluación.

The study investigates methods to enhance the reliability of NO2 monitoring using low-cost electrochemical sensors to measure gaseous pollutants in air by addressing the impacts of temperature and relative humidity. The temperature within a plastic container was controlled using an internal mica heater, an external hot air blower, or cooling packs, while relative humidity was adjusted using glycerine solutions. Findings indicated that the auxiliary electrode signal is susceptible to temperature and moderately affected by relative humidity. In contrast, the working electrode signal is less affected by temperature and relative humidity; however, adjustments are still required to determine gas concentrations accurately. Tests involving on/off cycles showed that the auxiliary electrode signal experiences exponential decay before stabilizing, requiring the exclusion of initial readings during monitoring activities. Additionally, calibration experiments in zero air allowed the determination of the compensation factor nT across different temperatures and humidity levels. These results highlight the importance of compensating for temperature and humidity effects to improve the accuracy and reliability of NO2 measurements using low-cost electrochemical sensors. This refinement makes the calibration applicable across a broader range of environmental conditions. However, the experiments also show a lack of repeatability in the zero air calibration. [ABSTRACT FROM AUTHOR]

In developing nations, outdated technologies and sulfur-rich heavy fossil fuel usage are major contributors to air pollution, affecting urban air quality and public health. In addition, the limited resources hinder the adoption of advanced monitoring systems crucial for informed public health policies. This study addresses this challenge by introducing an affordable internet of things (IoT) monitoring system capable of tracking atmospheric pollutants and meteorological parameters. The IoT platform combines a Bresser 5-in-1 weather station with a previously developed air quality monitoring device equipped with Alphasense gas sensors. Utilizing MQTT, Node-RED, InfluxDB, and Grafana, a Raspberry Pi collects, processes, and visualizes the data it receives from the measuring device by LoRa. To validate system performance, a 15-day field campaign was conducted in Santa Clara, Cuba, using a Libelium Smart Environment Pro as a reference. The system, with a development cost several times lower than Libelium and measuring a greater number of variables, provided reliable data to address air quality issues and support health-related decision making, overcoming resource and budget constraints. The results showed that the IoT architecture has the capacity to process measurements in tropical conditions. The meteorological data provide deeper insights into events of poorer air quality. [ABSTRACT FROM AUTHOR]

This contribution shows the possibilities of applying a low-cost, multi-purpose data logger built around an Arduino Mega 2560 single-board computer. Most projects use this kind of hardware to develop single-purpose data loggers. In this work, a data logger with a more general hardware and software architecture was built to perform measurement campaigns in very different domains. The wide applicability of this data logger was demonstrated with short-term monitoring campaigns in relation to outdoor air quality, human activity in an office, motion of a journey on a bike, and exhaust gas monitoring of a diesel generator. In addition, an assessment process and corresponding evaluation framework are proposed to assess the credibility of low-cost scientific devices built in-house. The experiences acquired during the development of the system and the short measurement campaigns were used as inputs in the assessment process. The assessment showed that the system scores positively on most product-related targets. However, unexpected events affect the assessment over the longer term. This makes the development of low-cost scientific devices harder than expected. To assure stability and long-term performance of this type of design, continuous evaluation and regular engineering corrections are needed throughout longer testing periods. [ABSTRACT FROM AUTHOR]

Poor air quality is a global problem that affects human health and ecosystems all over the world. For that reason, many countries invest in networks of reference monitoring stations that measure air quality in real time. However, the high installation and maintenance costs of these stations mean that smaller cities or underdeveloped regions are less covered by such stations. In these regions, alternative detection technologies such as low-cost monitoring systems can be used instead. Unfortunately, the results of such monitoring devices are often questioned by academics. This contribution proposes the design of an air quality monitoring system where cost and reliability have been optimized from a hardware point of view. In addition, the device has been coupled to an IoT platform so that inexperienced users can view and share the collected information The design of affordable systems increases the ability to perform ad hoc analysis at the level of neighborhoods or cities by citizen science organizations or governmental entities. [ABSTRACT FROM AUTHOR]

In the Western world, the SO2 concentration in ambient air dropped to low levels, but some emission sources (e.g., merchant ships) and some regions (e.g., low-income countries) still emit substantial amounts of SO2. At those locations, SO2 monitoring is critical. However, low-income countries do not have much access to expensive reference instruments. Low-cost gas sensors might be an alternative, but it is unclear how reliable such measurements are. To evaluate the performance of the low-cost alternative, the same SO2 gas sensor has been subjected to three different calibration methods: (1) low-cost calibration performed in the tropical climate of Cuba; (2) high-end calibration performed in Belgium; (3) a field calibration at an air quality measuring station in Belgium. The first two methods showed similar trends, suggesting that the gas sensor can be calibrated with a low-cost method. The field calibration was hampered by the low SO2 concentrations. For the monitoring campaign in Cienfuegos, Cuba, the low-cost SO2 sensor calibrated by the low-cost method appeared to be sufficiently reliable. The reliability of the sensor increases with the increase in SO2 concentration, so it can be used in Cuba instead of Belgium. [ABSTRACT FROM AUTHOR]

Low-cost sensors provide an affordable alternative to monitor environmental parameters with acceptable performance. There is a substantial amount of literature where low-cost sensors are compared with high-end reference measurements. However, not all organizations have access to such reference infrastructure. We propose low-cost calibration methods for temperature, relative humidity, and CO2 to allow them to collect their own reliable data. These methods are based on simple techniques and procedures that allow temperature calibration to be achieved in the range of 0 to 50 °C, relative humidity from 0 to 90%, and CO2 between 0 and 1100 ppm. The materials used to create the calibration setups can be purchased online, at hardware stores, and in pharmacies. The reliability of the calibration methods was evaluated using several indicators, such as the airtightness of the calibration box, similarity with the factory calibration, similarity with the reference, similarity between different sensors, replicability of the calibration method, and the similarity with a golden standard. In addition, the results of the low-cost calibration methods were compared with the more advanced calibration methods. A short measurement campaign in the city of Santa Clara, Cuba, demonstrated that such calibrations transform in-house developed monitoring systems into valid low-cost scientific instruments for decision-making. This work creates opportunities for institutions and researchers hosted in low- and mid-income countries to build and validate their own equipment to reliably solve local problems. [ABSTRACT FROM AUTHOR]