Calibration Transfer Among Sensor Arrays Designed for Monitoring Volatile Organic Compounds in Indoor Air Quality

Wolfrum, Edward J.; Meglen, Robert M.; Peterson, Darren J.; Sluiter, Justin

doi:10.1109/jsen.2006.884558

Cited by 24 publications

(11 citation statements)

References 7 publications

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“…Improved spatial observations can support improved source apportionment, improved validation of emission and transport models and give better estimates of human exposure 1 . Arrays of air pollution sensors are now being deployed in both indoor 2,3,4,5 and outdoor 6,7,8 environments and there is increasing confidence in the quality of observations generated 4,7,8 .…”

Section: Introductionmentioning

confidence: 99%

“…Used in the laboratory, in combination with calibration models and multivariate regression it is possible to differentiate and semi-quantify VOCs 5,14,15 . Several studies have shown that MOS sensors often exhibit nonlinear responses towards VOCs 3,5,8 , although their response does become linear at VOC concentrations below 100 ppb, a value reasonably representative of ambient air 1,5 . Nonlinear relationships exist between MOS VOC sensitivity and other variables, for example RH and temperature, further complicating calibration and ambient use.…”

Section: Introductionmentioning

confidence: 99%

“…Nonlinear relationships exist between MOS VOC sensitivity and other variables, for example RH and temperature, further complicating calibration and ambient use. Sensitivities and response times can be different for notionally identical sensors 3,14,16 therefore transferring a single calibration model from the laboratory to deployment, and indeed from sensor to sensor is difficult 5 . There is an emerging literature showing that corrections for both chemical and environmental factors can be improved using more complex statistical models 13 that go beyond simple linear regressions, for example, using Partial Least Squares 14 , neural networks 17 or Gaussian process emulation 1 .…”

Section: Introductionmentioning

confidence: 99%

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Clustering approaches to improve the performance of low cost air pollution sensors

et al. 2017

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Article:Smith, Katie R., Edwards, Peter M. orcid.org/0000-0002-1076-6793, Evans, Mathew J. orcid.org/0000-0003-4775-032X et al. (5 more Low cost air pollution sensors have substantial potential for atmospheric research and for the applied control of pollution in the urban environment, including more localized warnings to the public. The current generation of single-chemical gas sensors experience degrees of interference from other co-pollutants and have sensitivity to environmental factors such as temperature, wind speed and supply voltage. There are uncertainties introduced also because of sensor-to-sensor response variability, although this is less well reported. The sensitivity of Metal Oxide Sensors (MOS) to volatile organic compounds (VOCs) changed with relative humidity (RH) by up to a factor of five over the range 19-90%RH and with an uncertainty in the correction of a factor two at any given RH. The short-term (second to minute) stabilities of MOS and electrochemical CO sensor responses were reasonable. During more extended use inter-sensor quantitative comparability was degraded due to unpredictable variability in individual sensor responses (to either measurand or interference or both) drifting over timescales of several hours to days. For timescales longer than a week identical sensors showed slow, often downwards, drifts in their responses which diverged across six CO sensors by up to 30% after two weeks. The measurement derived from the median sensor within clusters of 6, 8 and up to 21 sensors was evaluated against individual sensor performance and external reference values. The clustered approach maintained the cost competitiveness of a sensor device, but the median concentration from the ensemble of sensor signals largely eliminated the randomised hour-to-day response drift seen in individual sensors and excluded the effects of small numbers of poorly performing sensors that drifted significantly over longer time periods. The results demonstrate that for individual sensors to be optimally comparable to one another, and to reference instruments, they would likely require frequent calibration. The use of a cluster median value eliminates unpredictable medium term response changes, and other longer term outlier behaviours, extending the likely period needed between calibration and making a linear interpolation between calibrations more appropriate. Through the use of sensor clusters rather than individual sensors existing low cost technologies could deliver significantly improved quality of observations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Clustering approaches to improve the performance of low cost air pollution sensors

et al. 2017

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“…The majority of publications uses a classical calibration profile where the sensor is exposed to increasing (or decreasing) concentrations of one test gas in carrier gas. Repetitions or random shuffling of exposures are sometimes used to prevent confounding of effects, e. g., sensor response, memory effects, and long-term baseline drift [265], [301], [303], [304].…”

Section: Calibration Profilementioning

confidence: 99%

“…This number becomes much smaller for gas mixtures. In [309], two mixtures of two gases each (ethylene, methane, CO) with random concentrations are considered, and in [301], sixteen combinations of three VOCs at three fixed concentration levels are generated in several runs. Fixed concentration levels are also used in [310] to generate up to 24 different gas mixtures comprising up to five different gases.…”

Section: Calibration Profilementioning

confidence: 99%

Improving the Performance of Gas Sensor Systems with Advanced Data Evaluation, Operation, and Calibration Methods

Bastuck

2019

Linköping Studies in Science and Technology. Dissertations

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In order to facilitate the widespread use of gas sensors, some challenges must still be overcome. Many of those are related to the reliable quantification of ultra-low concentrations of specific compounds in a background of other gases. This thesis focuses on three important items in the measurement chain: sensor material and operating modes, evaluation of the resulting data, and test gas generation for efficient sensor calibration. New operating modes and materials for gas-sensitive field-effect transistors have been investigated. Tungsten trioxide as gate oxide can improve the selectivity to hazardous volatile organic compounds like naphthalene even in a strong and variable ethanol background. The influence of gate bias and ultraviolet light has been studied with respect to the transport of oxygen anions on the sensor surface and was used to improve classification and quantification of different gases. DAV 3 E, an internationally recognized MATLAB-based toolbox for the evaluation of cyclic sensor data, has been developed and published as opensource. It provides a user-friendly graphical interface and specially tailored algorithms from multivariate statistics. The laboratory tests conducted during this project have been extended with an interlaboratory study and a field test, both yielding valuable insights for future, more complex sensor calibration. A novel, efficient calibration approach has been proposed and evaluated with ten different gas sensor systems. i styrning och data-utvärdering som tagits fram har både en jämförande undersökning av modellernas/metodernas prestanda av två oberoende laboratorier och fält-mätningar i en av de tilltänkta tillämpningarna genomförts. Bl.a. baserat på resultaten och insikterna från dessa övningar har ett helt nytt angreppssätt avseende robust och effektiv kalibrering och kvalitets-utvärdering av sensor-system utvecklats och utvärderats för tio olika sensor-system. v Preface This dissertation is the result of my binational doctorate supervised by Prof.

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Pattern Recognition

Vito¹,

Falasconi²,

Pardo³

2016

Essentials of Machine Olfaction and Taste

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Calibration Transfer Among Sensor Arrays Designed for Monitoring Volatile Organic Compounds in Indoor Air Quality

Cited by 24 publications

References 7 publications

Clustering approaches to improve the performance of low cost air pollution sensors

Clustering approaches to improve the performance of low cost air pollution sensors

Improving the Performance of Gas Sensor Systems with Advanced Data Evaluation, Operation, and Calibration Methods

Pattern Recognition

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