Influence of wind-speed on short-duration NO 2 measurements using Palmes and Ogawa passive diffusion samplers

Masey, Nicola; Gillespie, Jonathan; Heal, Mathew R.; Hamilton, Scott; Beverland, Iain J.

doi:10.1016/j.atmosenv.2017.04.008

Cited by 19 publications

(12 citation statements)

References 24 publications

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“…The wind data were for Glasgow airport several km away from the PDT exposures in the centre of Glasgow. The average positive bias compared with the theoretical uptake rate for a PDT in the Masey et al [43] study was~25% across the 32 exposures of exposure-mean wind speeds ranging from~1 m s −1 to~8 m s −1 . The magnitude of this mean bias is similar to that reported by Martin et al [35] from their chamber experiments, but Martin et al [35] did not observe variation in their bias across their tested wind speed range of 0.5-2 m s −1 , whilst Masey et al [43] report substantial variation with wind speed.…”

Section: Field Studiesmentioning

confidence: 83%

“…A very slightly increasing NO 2 bias with increasing exposure-average O 3 concentration was attributed to within-tube NO + O 3 reaction. The authors reported no significant trend of NO 2 bias with wind speed (which ranged from 2.7-4.7 m s −1 ), temperature (which ranged from 4-20 • C) or RH (which ranged from 65-90%), although they acknowledge that meteorological measurements were made some distance from the sampling sites, as also in the Masey et al [43] study, which could mean that wind speed in particular was different at the PDT locations.…”

Section: Field Studiesmentioning

confidence: 90%

“…Masey et al [43] assessed the precision and accuracy of NO 2 concentrations measured with standard Palmes PDTs (as well as other variants of passive sampler) over 32 separate two-day, three-day and seven-day exposure periods at an urban background site in Glasgow. PDTs were prepared by dipping grids in 50% TEA in acetone, and analysis followed the Defra WG [14] procedures.…”

Section: Field Studiesmentioning

confidence: 99%

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Biases in the Measurement of Ambient Nitrogen Dioxide (NO2) by Palmes Passive Diffusion Tube: A Review of Current Understanding

2019

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Palmes-type passive diffusion tubes (PDTs) are widely used to measure levels of nitrogen dioxide (NO2) in air quality studies. Molecules of NO2 diffuse down the concentration gradient established in the tube by their reactive conversion into nitrite (NO2−) with triethanolamine (TEA) absorbent at the inner end. The relatively low uptake rate for the tube geometry means that exposure-averaged NO2 concentration can be calculated from first principles using the diffusion coefficient, D, for NO2 in air. This review provides a critical assessment of the current understanding of sources and extent of potential bias in NO2 PDT measurements in each of the following methodological stages: preparation of the absorbent; quantification of the absorbed NO2−; deployment in the field; calculation of the exposure-average NO2 concentration from the absorbed NO2−; and assessment of PDT bias through comparison against a chemiluminescence NO2 analyser. The review has revealed strong evidence that PDT measurement of NO2 can be subject to bias from a number of sources. The most significant positive biases are ambient wind flow at the entrance of the tube potentially leading to bias of tens of percent, and within-tube chemical reaction between NO and O3 causing bias up to ~25% at urban background locations, but much less at roadside and rural locations. Sources of potentially significant negative bias are associated with deployment times of several weeks in warm and sunny conditions, and deployments in atmospheres with relative humidities <~75% which causes incomplete conversion of NO2 to NO2−. Evidence suggests that biases (positive or negative) can be introduced by individual laboratories in the PDT preparation and NO2− quantification steps. It is insufficiently acknowledged that the value of D is not accurately known—some controlled chamber experiments can be interpreted as indicating that the value of D currently used is too low, giving rise to a positive bias in PDT-derived NO2 concentration. More than one bias may be present in a given PDT deployment, and because the biases act independently the net effect on PDT NO2 determination is the linear sum of individual biases acting on that deployment. The effect of net bias can be reduced by application of a local “bias adjustment” factor derived from co-locations of PDTs with a chemiluminescence analyser. When this is carried out, the PDT is suitable as an indicative measure of NO2 for air quality assessments. However, it must be recognised that individual PDT deployments may be subject to unknown variation in the bias adjustment factor for that deployment.

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Section: Field Studiesmentioning

confidence: 83%

Section: Field Studiesmentioning

confidence: 90%

Section: Field Studiesmentioning

confidence: 99%

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Biases in the Measurement of Ambient Nitrogen Dioxide (NO2) by Palmes Passive Diffusion Tube: A Review of Current Understanding

2019

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“…NO 2 was passively sampled with an Ogawa pad and VOCs and PAHs were collected using a PDMS sorbent bar. While the NO 2 measurements using commercially-available Ogawa pads have been well described in the literature 51,52,69,70 , this is the first study to evaluate airborne VOC and PAH sampling by a PDMS sorbent bar mounted in a wearable device. Good reproducibility was found for all compounds but only higher molecular weight PAHs (>180 g/mol) were well retained in the PDMS sorbent bar for sampling periods >24 hours at room temperature.…”

Section: Laboratory Evaluation Of Pollutant Stability On the Pdms Sorbent Barmentioning

confidence: 99%

The Fresh Air Wristband: A Wearable Air Pollutant Sampler

Lin

Esenther

Mascelloni

et al. 2020

Environ. Sci. Technol. Lett.

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Evaluation of cumulative exposure to air pollutant mixtures has been challenged by traditional techniques due to the weight, limited battery life, and cost. The performance of a novel wearable air pollutant sampler, the Fresh Air wristband, to passively concentrate nitrogen dioxide (NO 2 ), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs) was investigated. The Fresh Air Wristband consisted of a commercially-available triethanolaminecoated pad to collect NO 2 and polydimethylsiloxane (PDMS) sorbent bar to sample VOCs and PAHs. Concentrations were measured off-line following the assessment period. The repeatability and rate of VOC and PAHs uptake by the PDMS sorbent bar was evaluated and the Fresh Air wristband was tested as exposure tool. The PDMS sorbent bar achieved reproducible uptake of from ambient air with uptake rates varying from 2 to 5 days across compounds. Higher molecular weight compounds (>180 g/mol) were well retained in the PDMS sorbent bar over multi-day periods. The Fresh Air wristband was demonstrated as a personal exposure tool; exposures of school-aged children were found to differ by sex, asthma status, home kitchen characteristics, and mode of travel to school. The lightweight, wearable Fresh Air wristband will enable future longitudinal air pollutant exposure assessment in vulnerable populations.

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“…However, the cost of these stations, together with practical considerations regarding suitable sites, invariably limits the spatial coverage of automatic networks. Wider geographical networks of passive diffusion samplers (PDS) can mitigate restrictions on spatial coverage [1,2]; however PDS provide limited temporal information, and can be subject to measurement inaccuracies associated with changing meteorological [3] and atmospheric chemistry conditions [4].…”

Section: Introductionmentioning

confidence: 99%

Temporal changes in field calibration relationships for Aeroqual S500 O3 and NO2 sensor-based monitors

Masey

Gillespie

Ezani

et al. 2018

Sensors and Actuators B: Chemical

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This version is available at https://strathprints.strath.ac.uk/64922/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. sensor output, and discrepancies between the 2 Aeroqual NO 2 sensors) resulted in relatively inaccurate concentrations estimates (cf. reference concentrations) from calibration equations derived in the first training period and applied to subsequent test deployments (e.g. NO 2 RMSE = 47.2 μgm −3 (n = 286) for a dataset of all test periods combined, for one of the two monitor pairs). Substantial improvements in accuracy of estimated concentrations were achieved by combination of repeated intermittent training data into a single calibration dataset (NO 2 RMSE = 8.5 μgm −3 for same test dataset described above). This latter approach to field calibration is recommended.

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Influence of wind-speed on short-duration NO 2 measurements using Palmes and Ogawa passive diffusion samplers

Cited by 19 publications

References 24 publications

Biases in the Measurement of Ambient Nitrogen Dioxide (NO2) by Palmes Passive Diffusion Tube: A Review of Current Understanding

Biases in the Measurement of Ambient Nitrogen Dioxide (NO2) by Palmes Passive Diffusion Tube: A Review of Current Understanding

The Fresh Air Wristband: A Wearable Air Pollutant Sampler

Temporal changes in field calibration relationships for Aeroqual S500 O3 and NO2 sensor-based monitors

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