scholarly journals Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

2018 ◽  
Vol 11 (6) ◽  
pp. 3569-3594 ◽  
Author(s):  
Ashley Collier-Oxandale ◽  
Joanna Gordon Casey ◽  
Ricardo Piedrahita ◽  
John Ortega ◽  
Hannah Halliday ◽  
...  
Keyword(s):  
Air Quality ◽  
Los Angeles ◽  
Oil And Gas ◽  
Spatial Scales ◽  
Low Cost ◽  
Urban Environments ◽  
Monitoring Networks ◽  
Linear Calibration ◽  
Spatial And Temporal Scales ◽  
Rural And Urban

Abstract. Low-cost sensors have the potential to facilitate the exploration of air quality issues on new temporal and spatial scales. Here we evaluate a low-cost sensor quantification system for methane through its use in two different deployments. The first was a 1-month deployment along the Colorado Front Range and included sites near active oil and gas operations in the Denver-Julesburg basin. The second deployment was in an urban Los Angeles neighborhood, subject to complex mixtures of air pollution sources including oil operations. Given its role as a potent greenhouse gas, new low-cost methods for detecting and monitoring methane may aid in protecting human and environmental health. In this paper, we assess a number of linear calibration models used to convert raw sensor signals into ppm concentration values. We also examine different choices that can be made during calibration and data processing and explore cross sensitivities that impact this sensor type. The results illustrate the accuracy of the Figaro TGS 2600 sensor when methane is quantified from raw signals using the techniques described. The results also demonstrate the value of these tools for examining air quality trends and events on small spatial and temporal scales as well as their ability to characterize an area – highlighting their potential to provide preliminary data that can inform more targeted measurements or supplement existing monitoring networks.

scholarly journals Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

2018 ◽  
Author(s):  
Ashley Collier-Oxandale ◽  
Michael P. Hannigan ◽  
Joanna Gordon Casey ◽  
Ricardo Piedrahita ◽  
John Ortega ◽  
...  
Keyword(s):  
Air Quality ◽  
Los Angeles ◽  
Oil And Gas ◽  
Spatial Scales ◽  
Low Cost ◽  
Complex Mixture ◽  
Urban Environments ◽  
Monitoring Networks ◽  
Linear Calibration ◽  
Spatial And Temporal Scales

Abstract. Low-cost sensors have the potential to facilitate the exploration of air quality issues on new temporal and spatial scales. Here we evaluate a low-cost sensor quantification system for methane through its use in two different deployments. The first, a one-month deployment along the Colorado Front Range includes sites near active oil and gas operations in the Denver-Julesberg basin. The second deployment in an urban Los Angeles neighborhood, an subject to complex mixture of air pollution sources including oil operations. Given its role as a potent greenhouse gas, new low-cost methods for detecting and monitoring methane may aid in protecting human and environmental health. In this paper, we assess a number of linear calibration models to convert raw sensor signals into ppm concentration values. We also examine different choices that can be made during calibration and data processing, and explore cross-sensitivities that impact this sensor type. The results illustrate the accuracy of the Figaro TGS 2600 sensor when methane is quantified from raw signals using the techniques described. The results also demonstrate the value of these tools for examining air quality trends and events on small spatial and temporal scales as well as their ability to characterize an area – highlighting their potential to provide preliminary data that can inform more targeted measurements or supplement existing monitoring networks.

scholarly journals Field Evaluation of Low-Cost PM Sensors (Purple Air PA-II) Under Variable Urban Air Quality Conditions, in Greece

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 926 ◽  
Author(s):  
Iasonas Stavroulas ◽  
Georgios Grivas ◽  
Panagiotis Michalopoulos ◽  
Eleni Liakakou ◽  
Aikaterini Bougiatioti ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Forest ◽  
Low Cost ◽  
Field Evaluation ◽  
Urban Environments ◽  
Spatiotemporal Variability ◽  
Monitoring Networks ◽  
Fire Event ◽  
Ambient Relative Humidity ◽  
Reference Measurements

Recent advances in particle sensor technologies have led to an increased development and utilization of low-cost, compact, particulate matter (PM) monitors. These devices can be deployed in dense monitoring networks, enabling an improved characterization of the spatiotemporal variability in ambient levels and exposure. However, the reliability of their measurements is an important prerequisite, necessitating rigorous performance evaluation and calibration in comparison to reference-grade instrumentation. In this study, field evaluation of Purple Air PA-II devices (low-cost PM sensors) is performed in two urban environments and across three seasons in Greece, in comparison to different types of reference instruments. Measurements were conducted in Athens (the largest city in Greece with nearly four-million inhabitants) for five months spanning over the summer of 2019 and winter/spring of 2020 and in Ioannina, a medium-sized city in northwestern Greece (100,000 inhabitants) during winter/spring 2019–2020. The PM2.5 sensor output correlates strongly with reference measurements (R2 = 0.87 against a beta attenuation monitor and R2 = 0.98 against an optical reference-grade monitor). Deviations in the sensor-reference agreement are identified as mainly related to elevated coarse particle concentrations and high ambient relative humidity. Simple and multiple regression models are tested to compensate for these biases, drastically improving the sensor’s response. Large decreases in sensor error are observed after implementation of models, leading to mean absolute percentage errors of 0.18 and 0.12 for the Athens and Ioannina datasets, respectively. Overall, a quality-controlled and robustly evaluated low-cost network can be an integral component for air quality monitoring in a smart city. Case studies are presented along this line, where a network of PA-II devices is used to monitor the air quality deterioration during a peri-urban forest fire event affecting the area of Athens and during extreme wintertime smog events in Ioannina, related to wood burning for residential heating.

Utility of a Low-Cost, Dense Sensor Network for the Study of Air Quality Impact Upon Human Health in Urban and Rural Areas

2019 ◽  
Vol 38 (1) ◽  
pp. 1-14
Author(s):  
Susan Alexander ◽  
Aaron Kaulfus ◽  
C. E. Phillips ◽  
Bob Baron ◽  
John N. McHenry ◽  
...  
Keyword(s):  
Air Quality ◽  
Rural Areas ◽  
Urban Areas ◽  
Low Cost ◽  
Health Impact ◽  
Monitoring Networks ◽  
Rural And Urban Areas ◽  
Rural And Urban ◽  
Recent Emergence ◽  
Urban And Rural Areas

The chemical composition of air changes from moment to moment. While the atmosphere may appear clear and cloudless to the human eye, gases, aerosols, and particulates are in constant interaction with Earth's surface under the influence of meteorological conditions. The recent emergence of low-cost, dense environmental air quality monitoring networks suggests growing interest in highly granular temporospatial exposure assessments by scientists and citizens. This chapter describes the utility of leveraging partnerships and resources to collocate a dense network of low-cost air quality sensors with meteorological sensors across a predominantly rural state located in the southeastern U.S. Construction of the network will improve knowledge on the daily, diurnal, and seasonal variations of pollutant exposures in rural and urban areas, the public health impact of extreme climatological and atmospheric events, and socioeconomic factors that heighten risk of exposures and health outcomes.

scholarly journals Low-Cost Air Quality Sensors: One-Year Field Comparative Measurement of Different Gas Sensors and Particle Counters with Reference Monitors at Tušimice Observatory

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 492 ◽  
Author(s):  
Petra Bauerová ◽  
Adriana Šindelářová ◽  
Štěpán Rychlík ◽  
Zbyněk Novák ◽  
Josef Keder
Keyword(s):  
Air Quality ◽  
Gas Sensors ◽  
Low Cost ◽  
Monitoring Network ◽  
Field Testing ◽  
Ambient Air ◽  
Monitoring Networks ◽  
Comparative Measurement ◽  
One Year ◽  
Pm2.5 And Pm10

With attention increasing regarding the level of air pollution in different metropolitan and industrial areas worldwide, interest in expanding the monitoring networks by low-cost air quality sensors is also increasing. Although the role of these small and affordable sensors is rather supplementary, determination of the measurement uncertainty is one of the main questions of their applicability because there is no certificate for quality assurance of these non-reference technologies. This paper presents the results of almost one-year field testing measurements, when the data from different low-cost sensors (for SO2, NO2, O3, and CO: Cairclip, Envea, FR; for PM1, PM2.5, and PM10: PMS7003, Plantower, CHN, and OPC-N2, Alphasense, UK) were compared with co-located reference monitors used within the Czech national ambient air quality monitoring network. The results showed that in addition to the given reduced measurement accuracy of the sensors, the data quality depends on the early detection of defective units and changes caused by the effect of meteorological conditions (effect of air temperature and humidity on gas sensors and effect of air humidity with condensation conditions on particle counters), or by the interference of different pollutants (especially in gas sensors). Comparative measurement is necessary prior to each sensor’s field applications.

In situ biomonitoring of air quality in rural and urban environments of Mexico Valley through genotoxicity evaluated in wild plants

2018 ◽  
Vol 9 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Sandra Gómez-Arroyo ◽  
Josefina Cortés-Eslava ◽  
Paola Loza-Gómez ◽  
Francisco Arenas-Huertero ◽  
Michel Grutter de la Mora ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Environments ◽  
Wild Plants ◽  
Rural And Urban

Low-Cost Air Quality Sensor Network in Munich

2020 ◽  
Author(s):  
Daniel Zollitsch ◽  
Jia Chen ◽  
Florian Dietrich ◽  
Benno Voggenreiter ◽  
Luca Setili ◽  
...  
Keyword(s):  
Air Quality ◽  
Real Time ◽  
Air Pollutants ◽  
Low Cost ◽  
Environmental Parameters ◽  
Calibration Method ◽  
Sensitivity Function ◽  
Machine Learning Algorithms ◽  
Urban Air ◽  
Monitoring Networks

<p>As the number of official monitoring stations for measuring urban air pollutants such as nitrogen oxides (NOx), particulate matter (PM) or ozone (O<sub>3</sub>) in most cities is quite small, it is difficult to determine the real human exposure to those pollutants. Therefore, several groups have established spatially higher resolved monitoring networks using low-cost sensors to create a finer concentration map [1-3].</p><p>We are currently establishing a low-cost, but high-accuracy network in Munich to measure the concentrations of NOx, PM, O<sub>3</sub>, CO and additional environmental parameters. For that, we developed a compact stand-alone sensor systems that requires low power, automatically measures the respective parameters every minute and sends the data to our server. There the raw data is transferred into concentration values by applying the respective sensitivity function for each sensor. These functions are determined by calibration measurements prior to the distribution of the sensors.</p><p>In contrast to the other existing networks, we will apply a recurring calibration method using a mobile high precision calibration unit (reference sensor) and machine learning algorithms. The results will be used to update the sensitivity function of each single sensor twice a week.  With the help of this approach, we will be able to create a calibrated real-time concentration map of air pollutants in Munich.</p><p>[1] Bigi et al.: Performance of NO, NO<sub>2</sub> low cost sensors and three calibration approaches within a real world application, Atmos. Meas. Tech., 11, 3717–3735, 2018</p><p>[2] Popoola et al., “Use of networks of low cost air quality sensors to quantify air quality in urban settings,” Atmos. Environ., 194, 58–70, 2018</p><p>[3] Schneider et al.: Mapping urban air quality in near real-time using observations from low-cost sensors and model information, Environ. Int., 106, 234–247, 2017</p>

scholarly journals Soil and nutrient losses in erosion gullies at different degrees of restoration

2010 ◽  
Vol 34 (3) ◽  
pp. 945-954 ◽  
Author(s):  
Roriz Luciano Machado ◽  
Alexander Silva de Resende ◽  
Eduardo Francia Carneiro Campello ◽  
José Arimathéa Oliveira ◽  
Avílio Antônio Franco
Keyword(s):  
Low Cost ◽  
Soil Classification ◽  
Urban Environments ◽  
Nutrient Loss ◽  
Data Sets ◽  
Nutrient Losses ◽  
Sediment Grain Size ◽  
Rural And Urban ◽  
Soil Sediment

The most advanced stage of water erosion, the gully, represents severe problems in different contexts, both in rural and urban environments. In the search for a stabilization of the process in a viable manner it is of utmost importance to assess the efficiency of evaluation methodologies. For this purpose, the efficiency of low-cost conservation practices were tested for the reduction of soil and nutrient losses caused by erosion from gullies in Pinheiral, state of Rio de Janeiro. The following areas were studied: gully recovered by means of physical and biological strategies; gullies in recovering stage, by means of physical strategies only, and gullies under no restoration treatment. During the summer of 2005/2006, the following data sets were collected for this study: soil classification of each of the eroded gully areas; planimetric and altimetric survey; determination of rain erosivity indexes; determination of amount of soil sediment; sediment grain size characteristics; natural amounts of nutrients Ca, Mg, K and P, as well as total C and N concentrations. The results for the three first measurements were 52.5, 20.5, and 29.0 Mg in the sediments from the gully without intervention, and of 1.0, 1.7 and 1.8 Mg from the gully with physical interventions, indicating an average reduction of 95 %. The fully recovered gully produced no sediment during the period. The data of total nutrient loss from the three gullies under investigation showed reductions of 98 % for the recovering gully, and 99 % for the fully recovered one. As for the loss of nutrients, the data indicate a nutrient loss of 1,811 kg from for the non-treated gully. The use of physical and biological interventions made it possible to reduce overall nutrient loss by more than 96 %, over the entire rainy season, as compared to the non-treated gully. Results show that the methods used were effective in reducing soil and nutrient losses from gullies.

scholarly journals PLUVIÔMETRO DE BAIXO CUSTO E A VARIAÇÃO DA CHUVA NO MUNICÍPIO DE BARRA DO GARÇAS – MT (OUTUBRO DE 2015 A ABRIL DE 2016)

2017 ◽  
Vol 3 (8) ◽  
pp. 107
Author(s):  
Romário Rosa de Sousa
Keyword(s):  
Low Cost ◽  
Rainfall Variability ◽  
Rain Gauge ◽  
Urban Environments ◽  
Data Interpolation ◽  
Rain Gauges ◽  
Rural And Urban ◽  
Electronic Spreadsheet ◽  
Map Data ◽  
Rainfall Map

LOW COST RAIN GAUGES AND RAINFALL VARIABILITY IN BARRA DO GARÇAS – MT (OCTOBER 2015 TO APRIL 2016)PLUVIÓMETRO DE BAJO COSTO Y LA VARIACIÓN DE LA LLUVIA EN EL MUNICIPIO DE BARRA DO GARÇAS – MT (OCTUBRE DE 2015 A ABRIL 2016)Este trabalho teve como objetivo principal confeccionar e distribuir vinte pluviômetros de baixo custo de PVC, dentro do município de Barra do Garças-MT, onde posteriormente a partir dos dados coletados, gerou-se um mapa pluviométrico da irregularidade da chuva. Os trabalhos metodológicos foram desenvolvidos em onze etapas distintas. Após toda a fase de aquisição dos materiais de baixo custo, na sequência realizou-se os seguintes procedimentos: confecção dos pluviômetros, aferição, instalação, treinamento dos produtores rurais, coleta de dados a campo, organização dos dados em planilha eletrônica com geração de relatório de tabela dinâmica, realização do processo de interpolação dos dados, geração do mapa pluviométrico, ajustes e finalização do mapa gerado, análise e discussão dos dados. É importante ressaltar que o processo de interpolação dos dados foi realizado no software ArcGis, 10.1. Ressalta-se que o processo de construção do pluviômetro de baixo custo, demonstrou que foi de grande ajuda, no sentido de baixar custos com um instrumento de grande importância para o meio rural e urbano. Também ficou comprovado que o pluviômetro de baixo custo, é um aparelho de credibilidade e confiabilidade nos registros dos dados pluviométricos. Quanto a distribuição pluviométrica da chuva no município de Barra do Garças-MT, foi bem diversificada e irregular para o período estudado, onde averiguou-se que o maior acumulo pluviométrico foi registrado no extremo sul do município com 986,1mm de chuva. E encontra partida um núcleo seco com um baixo volume de precipitação foi confirmado na porção leste com 146,2 mm de chuva.Palavras-chave: Pluviômetros; Chuva; PVC; Baixo Custo.ABSTRACTThis study aims to design, assemble and distribute twenty low cost PVC rain gauges in Barra do Garças-MT, where afterwards a rainfall map was generated from the collected data. The methodological works were developed in eleven distinct stages. Following the entire acquisition phase of the low cost materials, the following procedures were carried out: preparation of the rain gauges, gauging, installation, training of rural producers, data collection in the field, data organization in electronic spreadsheet making a dynamic table report, data interpolation, creating a rainfall map, adjustment and finalization of the created map, data analysis and discussion. It is important to note the data interpolation process was performed in ArcGis software, 10.1. It should be noted that the process of construction of the low cost rain gauge showed that it was of great help in order to reduce costs with an instrument of great importance for the rural and urban environments. It has also been proven that the low cost rain gauge is an apparatus of credibility and reliability in rainfall records. As for the rainfall distribution in Barra do Garças-MT, it was well diversified and irregular for the period studied, where it was verified that the highest rainfall accumulation was recorded in the southern end of the municipality with 986.1mm of rain. However, finding a dry core with a low volume of precipitation was confirmed in the eastern portion with 146.2mm of rain.Keywords: Rain Gauges; Rain; PVC; Low Cost.RESUMENEste trabajo tuvo como objetivo principal elaborar, montar y distribuir veinte pluviómetros de bajo costo de PVC, dentro del municipio de Barra do Garças-MT, posteriormente, a partir de los datos colectados, se originó un mapa pluviométrico de la irregularidad de la lluvia. Los trabajos metodológicos fueron desarrollados en once etapas distintas. Después de toda la fase de adquisición de los materiales de bajo costo, en seguida se realizaron los siguientes procedimientos: confección de los pluviómetros, calibración, instalación, entrenamiento de los productores rurales, colecta de datos a campo, organización de los datos en planilla electrónica con elaboración de un informe de tabla dinámica, realización del proceso de interpolación de los datos, producción del mapa pluviométrico, ajustes y finalización del mapa generado, análisis y discusión de los datos. Es importante realzar que el proceso de interpolación de los datos fueron realizados en el software ArcGis, 10.1. Se resalta que el proceso de construcción del pluviómetro de bajo costo, demostró que fue de gran ayuda, en el sentido de bajar costos con un instrumento de gran importancia para el medio rural y urbano. También quedó demostrado que el pluviómetro de bajo costo, es un aparato de credibilidad y confiabilidad en los registros de los datos pluviométricos. Cuanto a la distribución pluviométrica en el municipio de Barra do Garças-MT, fue bien diversificada e irregular para el periodo estudiado, donde se comprobó que el mayor acúmulo pluviométrico fue registrado en el extremo Sur del municipio con 986,1mm de lluvia. En contra partida un núcleo seco con un bajo volumen de precipitación fue confirmado en la región Este con 146,2 mm de lluvia.Palabras-clave: Pluviómetros; Lluvia; PVC; Bajo Costo.

scholarly journals Design of an ozone and nitrogen dioxide sensor unit and its long-term operation within a sensor network in the city of Zurich

2017 ◽  
Author(s):  
Michael Mueller ◽  
Jonas Meyer ◽  
Christoph Hueglin
Keyword(s):  
Air Quality ◽  
Sensor Network ◽  
Data Transfer ◽  
Low Cost ◽  
Effective Procedure ◽  
Quality Monitoring ◽  
Air Quality Monitoring ◽  
Monitoring Networks ◽  
Term Operation ◽  
Diffusion Tubes

Abstract. This study focuses on the investigation and quantification of low-cost sensor performance in application fields such as the extension of traditional air quality monitoring networks or the replacement of diffusion tubes. For this, sensor units consisting of two boxes featuring NO2 and O3 low-cost sensors and wireless data transfer were engineered. The sensor units were initially operated at air quality monitoring sites for three months for performance analysis and initial calibration. Afterwards, they were relocated and operated within a sensor network consisting of six locations for more than one year. Our analyses show that the employed O3 and NO2 sensors can be accurate to 2–5 and 5–7 ppb, respectively, during the first three months of operation. This accuracy, however, could not be maintained during their operation within the sensor network related to changes in sensor behaviour. Hence, the low-cost sensors in our configuration do not reach the accuracy level of NO2 diffusion tubes. Tests in the laboratory revealed that changes in relative humidity can impact the signal of the employed NO2 sensors similarly as changes in ambient NO2 concentration. All the employed low-cost sensors need to be individually calibrated. Best performance of NO2 sensors is achieved when the calibration models include also time dependent parameters accounting for changes in sensor response over time. Accordingly, an effective procedure for continuous data control and correction is essential for obtaining meaningful data. It is demonstrated that linking the measurements from low-cost sensors to the high quality measurements from routine air quality monitoring stations is an effective procedure for both tasks provided that time periods can be identified when pollutant concentrations can be accurately predicted at sensor locations.

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