Monitoring of tropospheric ozone in the ambient air with passive samplers

2011 ◽  
Vol 99 (2) ◽  
pp. 383-387 ◽  
Author(s):  
Daniellys Alejo ◽  
Mayra C. Morales ◽  
Vladimir Nuñez ◽  
László Bencs ◽  
René Van Grieken ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Ambient Air ◽  
Passive Samplers

scholarly journals THE INFLUENCE OF ABSORBENT SOLUTION ON THE EFFECTIVENESS OF PASSIVE DIFFUSIVE SAMPLERS

2010 ◽  
Vol 2 (5) ◽  
pp. 103-108 ◽  
Author(s):  
Vaida Šerevičienė ◽  
Vaida Valuntaitė ◽  
Dainius Paliulis
Keyword(s):  
Aqueous Solutions ◽  
Ambient Air ◽  
Gas Diffusion ◽  
Passive Samplers ◽  
Oxides Of Nitrogen ◽  
The European Union ◽  
Absorption Mechanism ◽  
True Meaning ◽  
Almost All ◽  
Absorbent Solution

The method of applying passive diffusive samplers for research on air quality is simple, easy enough and requires no electricity. The operating principle of almost all passive samplers is based on chemical reactions taking place on absorbent (impregnated filter or grid). The pollutant absorption mechanism is based on passive diffusion through the gas diffusion layer to absorbent. The diffusion process can be explained by first Fick’s law described as a free movement of gases from the ambient air to a passive sampler. This movement depends on pollutant gradient. The aim of this paper is to analyse the influence of an impregnating solution on the efficiency of diffusive samplers. The object of the study covers the triethanolamine (TEA) aqueous solutions of 5%, 10%, 20%, 30% and 50%. The results obtained showed that 30% and 50% aqueous solution gave 68% and 89% relative error making the true meaning of the oxides of nitrogen analyzer testimony. Data on the passive samplers impregnated with TEA aqueous solutions having concentrations of 5%, 10% and 20% are within definite 25% uncertainty established by the European Union Directives.

scholarly journals Development and Types of Passive Samplers for Monitoring Atmospheric NO2 and NH3 Concentrations

2001 ◽  
Vol 1 ◽  
pp. 513-529 ◽  
Author(s):  
Y.S. Tang ◽  
J.N. Cape ◽  
M.A. Sutton
Keyword(s):  
Rural Areas ◽  
Sampling Rate ◽  
Reference Method ◽  
Diffusion Path ◽  
Ambient Air ◽  
Passive Samplers ◽  
Diffusion Resistance ◽  
Positive Bias ◽  
Diffusion Tubes ◽  
Term Monitoring

Numerous passive samplers based on the ‘Palmes-tube’ have been developed for ambient air monitoring. In each case, the diffusion path length and/or crosssectional area are modified to achieve the desired sampling rate. ‘Tube-type’ samplers are low sensitivity samplers suitable for long-term monitoring, whereas the ‘badge-type’ samplers have faster sampling rates suited to short-term monitoring. In the U.K., diffusion tubes are widely used for monitoring nitrogen dioxide (NO2) and ammonia (NH3). The open-ended diffusion tubes are prone to positive bias caused by incursion of wind eddies, leading to a shortening of the diffusion path. By using a porous membrane at the inlet, wind incursion is prevented, but an additional diffusion resistance is imposed and it is necessary to calibrate the tubes against a reference method to obtain an effective sampling rate. For NO2 sampling, positive bias also arises from the reaction of NO with O3 within the sampler. The interference from the chemical reaction is severe close to NO sources, with errors up to 30% for curbside locations when using the ‘tubetype’ sampler. In rural areas, where NO concentrations are small relative to NO2, these errors are small. In some implementations, there is also a negative bias over long sampling periods caused by the degradation of trapped NO2. The low sampling rates of diffusion tubes make them too uncertain for use at background NH3 concentrations (<1 μg NH3 m-3) where they significantly overestimate concentrations. Badge-type samplers such as the ‘Willems badge’ samplers permit accurate sampling at low ambient NH3 concentrations, but suffer from saturation at high concentrations and sensitivity to wind speed. A passive sampler optimised for monthly measurements of NH3 is reported here, together with its application in the U.K. National Ammonia Monitoring Network.

Tropospheric ozone-induced structural changes in leaf mesophyll cell walls in grapevine plants

Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Nikola Ljubešić ◽  
Mihaela Britvec
Keyword(s):  
Cell Wall ◽  
Tropospheric Ozone ◽  
Cell Walls ◽  
Structural Changes ◽  
Mesophyll Cell ◽  
Ambient Air ◽  
Vitis Vinifera L ◽  
Mesophyll Cells ◽  
Ozone Concentrations ◽  
Leaf Mesophyll

AbstractThe structural changes in leaves of grapevine plants (Vitis vinifera L.) exposed to different ozone concentrations were investigated. Ozone fumigations were performed in open-top chambers at four different ozone levels (charcoal-filtered air (F), ambient air (N), ambient air + 25 mm3m−3 ozone (O-25) and ambient air + 50 mm3m−3 ozone (O-50)).The leaves of plants from chambers with increased ozone concentrations (O-25 and O-50) were significantly thicker than the controls (F), owing to increased thickness of the mesophyll layer. Observing O-50 leaves, it was found that the mesophyll cell wall displayed structural changes. In some places cell wall thickness increased up to 1 µm. We found callose deposits on the inner side of the cell walls of mesophyll cells. These data are in accord with the concept that the mesophyll cell wall acts as a barrier against the penetration of tropospheric ozone into the cells.

scholarly journals High NO2 Concentrations Measured by Passive Samplers in Czech Cities: Unresolved Aftermath of Dieselgate?

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 649
Author(s):  
Michal Vojtisek-Lom ◽  
Miroslav Suta ◽  
Jitka Sikorova ◽  
Radim J. Sram
Keyword(s):  
Hot Spots ◽  
Ambient Air ◽  
Passive Samplers ◽  
City Center ◽  
Clear Sign ◽  
Travel Restrictions ◽  
Emission Limit ◽  
Emission Limits ◽  
The City ◽  
The Eu

This work examines the effects of two problematic trends in diesel passenger car emissions—increasing NO2/NOx ratio by conversion of NO into NO2 in catalysts and a disparity between the emission limit and the actual emissions in everyday driving—on ambient air quality in Prague. NO2 concentrations were measured by 104 membrane-closed Palmes passive samplers at 65 locations in Prague in March–April and September–October of 2019. NO2 concentrations measured by city stations during those periods were comparable with the average values during 2016–2019. The average measured NO2 concentrations at the selected locations, after correcting for the 18.5% positive bias of samplers co-located with a monitoring station, were 36 µg/m3 (range 16–69 µg/m3, median 35 µg/m3), with the EU annual limit of 40 µg/m3 exceeded at 32% of locations. The NO2 concentrations have correlated well (R2 = 0.76) with the 2019 average daily vehicle counts, corrected for additional emissions due to uphill travel and intersections. In addition to expected “hot-spots” at busy intersections in the city center, new ones were identified, i.e., along a six-lane road V Holešovičkách. Comparison of data from six monitoring stations during 15 March–30 April 2020 travel restrictions with the same period in 2016–2019 revealed an overall reduction of NO2 and even a larger reduction of NO. The spatial analysis of data from passive samplers and time analysis of data during the travel restrictions both demonstrate a consistent positive correlation between traffic intensity and NO2 concentrations along/near the travel path. The slow pace of NO2 reductions in Prague suggests that stricter vehicle NOx emission limits, introduced in the last decade or two, have so far failed to sufficiently reduce the ambient NO2 concentrations, and there is no clear sign of remedy of Dieselgate NOx excess emissions.

scholarly journals Development of a highly sensitive sampler for atmospheric monitoring of 8-H ambient ozone concentrations

2020 ◽  
Vol 25 (6) ◽  
pp. 938-945
Author(s):  
Gülnihal KARA
Keyword(s):  
Urban Areas ◽  
Sampling Rate ◽  
Composite Membranes ◽  
Ambient Air ◽  
Absorption Capacity ◽  
Passive Sampler ◽  
Passive Samplers ◽  
Winter Period ◽  
Highly Sensitive ◽  
Measurement Results

A new passive sampler reinforced with a composite membrane was developed to determine the 8-h ozone (O3) concentration in ambient air. The composite membrane's water absorption capacity and porosity values were found analyzing its surface morphology using Scanning Electron Microscopy (SEM).Ozone adsorption performance of this sampler was tested by a badge-type sampler and automated measurement results. The developed sampler gave results equivalent (R<sup>2</sup> = 0.85) to those of automated O3 monitors, and its experimental sampling rate was determined to be 55 cm<sup>3</sup>/min, approximately two times higher than the rate of the badge-type sampler. The detection limit obtained (5.3 μg/m<sup>3<.sup>, 8 h sampling) in the study was adequate for winter-period samplings where in the ozone concentration is low in urban and semi-urban areas. Multimedia sampling results revealed that the results of the developed passive sampler had a high repeatability (RSD < 20%). Passive samplers reinforced with composite membranes were tested by badge-type samplers performing simultaneous samplings in land conditions. Area sampling results indicated that badge-type samplers were not suitable for 8-h area samplings, but tube-type samplers could be used.

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