Development of low-cost ozone and nitrogen dioxide measurement instruments suitable for use in an air quality monitoring network

Williams, David E.; Salmond, Jennifer; Yung, Yu Fai; Akaji, Jin; Wright, Bryon; Wilson, Jarod; Henshaw, Geoffrey S; Wells, D. B.; Ding, George; Wagner, J.K.; Laing, Greer

doi:10.1109/icsens.2009.5398568

Cited by 13 publications

(12 citation statements)

References 17 publications

(21 reference statements)

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“…The development of a sensor for ozone (O 3 ) and nitrogen dioxide (NO 2 ) with sensitivities at less that 10 ppb was reported by Williams et al [ 73 ]. The sensor is based on a film of tungsten oxide (WO 3 ) of ∼90 μm thickness, screen-printed on to gold electrodes.…”

Section: Nitrogen Oxide (No X ) Sensorsmentioning

confidence: 99%

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Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring

Fine

Cavanagh

Afonja

et al. 2010

Sensors

1,297

660

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Metal oxide semiconductor gas sensors are utilised in a variety of different roles and industries. They are relatively inexpensive compared to other sensing technologies, robust, lightweight, long lasting and benefit from high material sensitivity and quick response times. They have been used extensively to measure and monitor trace amounts of environmentally important gases such as carbon monoxide and nitrogen dioxide. In this review the nature of the gas response and how it is fundamentally linked to surface structure is explored. Synthetic routes to metal oxide semiconductor gas sensors are also discussed and related to their affect on surface structure. An overview of important contributions and recent advances are discussed for the use of metal oxide semiconductor sensors for the detection of a variety of gases—CO, NOx, NH3 and the particularly challenging case of CO2. Finally a description of recent advances in work completed at University College London is presented including the use of selective zeolites layers, new perovskite type materials and an innovative chemical vapour deposition approach to film deposition.

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Section: Nitrogen Oxide (No X ) Sensorsmentioning

confidence: 99%

“…X-axis indicates hours since experiment start and y-axis ppb concentration of NO 2 . Figure adapted with permission from [ 73 ].…”

Section: Figurementioning

confidence: 99%

Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring

Fine

Cavanagh

Afonja

et al. 2010

Sensors

1,297

660

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“…However, the quality of the data generated by these monitors compared with established techniques remains a concern (Snyder et al, 2013), in particular interference in the sensing of NO 2 by O 3 (Williams et al, 2009;Mead et al, 2013). One such type of monitor is the Aeroqual Ltd. Series 500 ENV portable gas monitors (www.aeroqual.com/category/ products/handheld-monitors).…”

Section: Introductionmentioning

confidence: 97%

“…These are relatively compact and lightweight (460 g), and can be operated from an inbuilt battery (for~8 h) or from mains power. Interchangeable metal oxide semiconductor and electrochemical sensors permit continuous monitoring of a range of gases at low mixing ratios (Williams et al, 2009). The Aeroqual monitors are a factor of approximately 5e10 times lower cost than standard air quality monitoring instrumentation for these gases.…”

Section: Introductionmentioning

confidence: 99%

Evaluation and calibration of Aeroqual series 500 portable gas sensors for accurate measurement of ambient ozone and nitrogen dioxide

Lin

Gillespie

Schuder

et al. 2015

Atmospheric Environment

111

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Low-power, and relatively low-cost, gas sensors have potential to improve understanding of intra-urban air pollution variation by enabling data capture over wider networks than is possible with 'traditional' reference analysers. We evaluated an Aeroqual Ltd. Series 500 semiconducting metal oxide O3 and an electrochemical NO2 sensor against UK national network reference analysers for more than 2months at an urban background site in central Edinburgh. Hourly-average Aeroqual O3 sensor observations were highly correlated (R2=0.91) and of similar magnitude to observations from the UV-absorption reference O3 analyser. The Aeroqual NO2 sensor observations correlated poorly with the reference chemiluminescence NO2 analyser (R2=0.02), but the deviations between Aeroqual and reference analyser values ([NO2]Aeroq-[NO2]ref) were highly significantly correlated with concurrent Aeroqual O3 sensor observations [O3]Aeroq. This permitted effective linear calibration of the [NO2]Aeroq data, evaluated using 'hold out' subsets of the data (R2≥0.85). These field observations under temperate environmental conditions suggest that the Aeroqual Series 500 NO2 and O3 monitors have good potential to be useful ambient air monitoring instruments in urban environments provided that the O3 and NO2 gas sensors are calibrated against reference analysers and deployed in parallel

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“…High density monitoring networks may thus be the primary solution to assess local variations in communal and infrastructural planning. This approach is being supported by the recent availability of low cost instruments such as those reported in Williams et al (, ). The low cost instruments are, however, seldom able to provide the reliability and accuracy of high‐end reference instruments (Zhang et al , , ).…”

Section: Introductionmentioning

confidence: 94%

Detection of malfunctions in sensor networks

Alavi¹,

Williams²,

Salmond

et al. 2013

Environmetrics

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Due to the increasing availability of sensors of moderate cost, large scale sensor networks are currently considered for different tasks. One of these is the monitoring of air quality with several, possibly hundreds of sensors that may cover an extensive area, or may be difficult to access. In this paper, we consider the detection of sensor malfunctions in sensor networks. A change in the statistics of a particular sensor can be either due to local variability or a malfunction, and thus simple change detection approaches do not necessarily apply. Here, we estimate the output of each sensor based on all the other sensors using approximate Wiener filters. The approach focuses on the variance of the related prediction errors and also facilitates the control of the trade‐off between the probability of detecting a potential sensor malfunction and the related degree of errors. As a case study, we consider daily ozone data from the Houston air quality monitoring network. Copyright © 2013 John Wiley & Sons, Ltd.

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Development of low-cost ozone and nitrogen dioxide measurement instruments suitable for use in an air quality monitoring network

Cited by 13 publications

References 17 publications

Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring

Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring

Evaluation and calibration of Aeroqual series 500 portable gas sensors for accurate measurement of ambient ozone and nitrogen dioxide

Detection of malfunctions in sensor networks

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