Search

In this research, several SO2 removal alternatives were evaluated for the treatment of gaseous effluents generated by the "Carlos Manuel de Céspedes" power plant in Cienfuegos to be use in gaseous stream to Ulva lettuce intensive culture. A low-cost sensor was used to monitor the gas concentration during the proposed methods. The sensor was previously calibrated and a linear regression model with a coefficient of determination of 0,9926 was obtained. The alternatives evaluated were adsorption with activated carbon, absorption with calcium hydroxide and absorption with seawater. The removal was evaluated at three levels SO2 concentration. In addition, the parameters pH, salinity and alkalinity were determined to a seawater sample from the Bay of Cienfuegos and with which the experiments were carried out. The values obtained were 8,17±0,003; 26,50±0,10 ups and 171,67±1,03 mg/L respectively, which confirms its good performance for gas removal. The three methods studied showed satisfactory results for SO2 removal. The seawater absorption experiment was the most efficient alternative, achieving the lowest final concentrations in the shortest time.

Introducción: Las emisiones de gases contaminantes a la atmósfera de los sistemas de generación de vapor están determinadas por el tipo y la composición del combustible. El fuel oíl con alto contenido de azufre es el responsable de las emisiones de dióxido de azufre. Es necesario conocer la incidencia en la calidad del aire de este contaminante desde una fuente fija, como una industria de recape, en el radio higiénico sanitario. Objetivo: Cuantificar el dióxido de azufre generado en una recapadora de neumáticos mediante medidas de emisión e inmisión en la zona higiénico sanitaria de la misma. Materiales y Métodos: Se desarrolló una metodología que incluye el inventario de emisiones de SO2 en función del consumo de combustible para la generación de vapor, la modelación de la dispersión y la evaluación de la inmisión mediante monitoreo con sensor de bajo costo. Resultados y Discusión: Los resultados evidencian que el SO2 en el aire ambiental determinados por modelación de la emisión y monitoreados con sensores de bajo costo son similares y no superan el valor límite establecido. Conclusiones: Los resultados de la concentración de SO2 evaluada con medidas de emisión e inmisión, demuestran que es la industria de recape la fuente principal que tributa a la calidad del aire por el efecto de este contaminante y en este estudio es aceptable. Además, la similitud de los valores de inmisión y la modelación de la emisión justifican la factibilidad del uso de sensores de bajo costo para medir la calidad del aire.

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.

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.

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.