Evaluating the PAS-SIM model using a passive air sampler calibration study for pesticides

Restrepo, Alberto; Hayward, Stephen; Armitage, James M.; Wania, Frank

doi:10.1039/c5em00122f

Cited by 16 publications

(30 citation statements)

References 34 publications

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“…The slope of the regression of m against C × t ( McLagan et al, 2016b;Restrepo et al, 2015) gave a very similar SR of 0.109 ± 0.009 m 3 day −1 . Because the latter method is thought to give a slightly more reliable SR (McLagan et al, 2016b;Restrepo et al, 2015), we suggest using this SR for indoor deployments of the PAS using the white Radiello and a protective shield (configuration 1). This SR is 9.9 % lower than the SR obtained in an earlier outdoor calibration study, despite the higher temperature (∼ 23 • C) indoors than outdoors (mean temperature across all deployments: 7.6 • C).…”

Section: S Mclagan Et Almentioning

confidence: 85%

The effects of meteorological parameters and diffusive barrier reuse on the sampling rate of a passive air sampler for gaseous mercury

et al. 2017

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Abstract. Passive air sampling of gaseous mercury (Hg) requires a high level of accuracy to discriminate small differences in atmospheric concentrations. Meteorological parameters have the potential to decrease this accuracy by impacting the sampling rate (SR), i.e., the volume of air that is effectively stripped of gaseous mercury per unit of time. We measured the SR of a recently calibrated passive air sampler for gaseous Hg in the laboratory under varying wind speeds (wind still to 6 m s −1 ), temperatures (−15 to +35 • C), and relative humidities (44 to 80 %). While relative humidity has no impact on SR, SR increases slightly with both wind speed (0.003 m 3 day −1 increase in SR or 2.5 % of the previously calibrated SR for every m s −1 increase for wind speeds > 1 m s −1 , typical of outdoor deployments) and temperature (0.001 m 3 day −1 increase in SR or 0.7 % for every 1 • C increase). The temperature dependence can be fully explained by the effect of temperature on the molecular diffusivity of gaseous mercury in air. Although these effects are relatively small, accuracy can be improved by adjusting SRs using measured or estimated temperature and wind speed data at or near sampling sites. We also assessed the possibility of reusing Radiello ® diffusive barriers previously used in the passive air samplers. The mean rate of gaseous Hg uptake was not significantly different between new and previously used diffusive barriers in both lab and outdoor deployments, irrespective of the applied cleaning procedure. No memory effect from Radiellos ® previously deployed in a high Hg atmosphere was observed. However, a loss in replicate precision for the dirtiest Radiellos ® in the indoor experiment suggests that cleaning is advisable prior to reuse.

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Section: S Mclagan Et Almentioning

confidence: 85%

The effects of meteorological parameters and diffusive barrier reuse on the sampling rate of a passive air sampler for gaseous mercury

et al. 2017

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“…7A). 26 This sampler has been extensively characterised in terms of the SR of different SVOCs in different climates 21,27,28,190 and with respect to the inuence of wind on the SR. 191 Experiments with different sampler congurations conrmed that the uptake rate is proportional to the surface area of the mesh cylinder 192 and both a short (10 cm) and long (20 cm) version of the sampler have been used. The deployment of multiple mesh cylinders in the same housing does not affect the SR, i.e.…”

Section: D23 Samplers Based On Polydimethyl Siloxane (Pdms)mentioning

confidence: 99%

“…8). 190 Each PAS can be treated as a single calibration experiment yielding an empirical SR e according to eqn (13). The overall SR e is then the average of the SR e obtained for each PAS.…”

Section: F the Sampling Rates Of Different Types Of Passmentioning

confidence: 99%

Passive air sampling for semi-volatile organic chemicals

Wania

Shunthirasingham

2020

Environ. Sci.: Processes Impacts

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“…The second set of air concentrations was calculated by using a recalibrated SR obtained from the data generated in this study plus the data from the original calibration experiment (hence termed recalibrated SR). This recalibrated SR was calculated using the slope method as described by Restrepo et al (2015) and McLagan et al (2016b). Rearranging Eq.…”

Section: Calculation Of Air Concentration From the Amount Taken Up Bymentioning

confidence: 99%

Global evaluation and calibration of a passive air sampler for gaseous mercury

et al. 2018

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Abstract. Passive air samplers (PASs) for gaseous mercury (Hg) were deployed for time periods between 1 month and 1 year at 20 sites across the globe with continuous atmospheric Hg monitoring using active Tekran instruments. The purpose was to evaluate the accuracy of the PAS vis-à-vis the industry standard active instruments and to determine a sampling rate (SR; the volume of air stripped of gaseous Hg per unit of time) that is applicable across a wide range of conditions. The sites spanned a wide range of latitudes, altitudes, meteorological conditions, and gaseous Hg concentrations. Precision, based on 378 replicated deployments performed by numerous personnel at multiple sites, is 3.6 ± 3.0 %1, confirming the PAS's excellent reproducibility and ease of use. Using a SR previously determined at a single site, gaseous Hg concentrations derived from the globally distributed PASs deviate from Tekran-based concentrations by 14.2 ± 10 %. A recalibration using the entire new data set yields a slightly higher SR of 0.1354 ± 0.016 m3 day−1. When concentrations are derived from the PAS using this revised SR the difference between concentrations from active and passive sampling is reduced to 8.8 ± 7.5 %. At the mean gaseous Hg concentration across the study sites of 1.54 ng m−3, this represents an ability to resolve concentrations to within 0.13 ng m−3. Adjusting the sampling rate to deployment specific temperatures and wind speeds does not decrease the difference in active–passive concentration further (8.7 ± 5.7 %), but reduces its variability by leading to better agreement in Hg concentrations measured at sites with very high and very low temperatures and very high wind speeds. This value (8.7 ± 5.7 %) represents a conservative assessment of the overall uncertainty of the PAS due to inherent uncertainties of the Tekran instruments. Going forward, the recalibrated SR adjusted for temperature and wind speed should be used, especially if conditions are highly variable or deviate considerably from the average of the deployments in this study (9.89 ∘C, 3.41 m s−1). Overall, the study demonstrates that the sampler is capable of recording background gaseous Hg concentrations across a wide range of environmental conditions with accuracy similar to that of industry standard active sampling instruments. Results at sites with active speciation units were inconclusive on whether the PASs take up total gaseous Hg or solely gaseous elemental Hg primarily because gaseous oxidized Hg concentrations were in a similar range as the uncertainty of the PAS.

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Evaluating the PAS-SIM model using a passive air sampler calibration study for pesticides

Cited by 16 publications

References 34 publications

The effects of meteorological parameters and diffusive barrier reuse on the sampling rate of a passive air sampler for gaseous mercury

The effects of meteorological parameters and diffusive barrier reuse on the sampling rate of a passive air sampler for gaseous mercury

Passive air sampling for semi-volatile organic chemicals

Global evaluation and calibration of a passive air sampler for gaseous mercury

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