scholarly journals Stability of halocarbons in air samples stored in stainless- steel canisters

2020 ◽  
Vol 13 (1) ◽  
pp. 73-84
Author(s):  
Tanja J. Schuck ◽  
Ann-Katrin Blank ◽  
Elisa Rittmeier ◽  
Jonathan Williams ◽  
Carl A. M. Brenninkmeijer ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Storage Time ◽  
Ambient Air ◽  
Sample Collection ◽  
Air Samples ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Halon 1301 ◽  
Stable Conditions ◽  
And Storage

Abstract. Measurements of halogenated trace gases in ambient air frequently rely on canister sampling followed by offline laboratory analysis. This allows for a large number of compounds to be analysed under stable conditions, maximizing measurement precision. However, individual compounds might be affected during the sampling and storage of canister samples. In order to assess halocarbon stability in whole-air samples from the upper troposphere and lowermost stratosphere, we performed stability tests using the high-resolution sampler (HIRES) air sampling unit, which is part of the Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container (CARIBIC) instrument package. The HIRES unit holds 88 lightweight stainless-steel cylinders that are pressurized in flight to 4.5 bar using metal bellows pumps. The HIRES unit was first deployed in 2010 but has up to now not been used for regular halocarbon analysis with the exception of chloromethane analysis. The sample collection unit was tested for the sampling and storage effects of 28 halogenated compounds. The focus was on compound stability in the stainless-steel canisters during storage of up to 5 weeks and on the influence of ozone, since flights take place in the upper troposphere and lowermost stratosphere with ozone mixing ratios of up to several hundred parts per billion by volume (ppbv). Most of the investigated (hydro)chlorofluorocarbons and long-lived hydrofluorocarbons were found to be stable over a storage time of up to 5 weeks and were unaltered by ozone being present during pressurization. Some compounds such as dichloromethane, trichloromethane, and tetrachloroethene started to decrease in the canisters after a storage time of more than 2 weeks or exhibited lowered mixing ratios in samples pressurized with ozone present. A few compounds such as tetrachloromethane and tribromomethane were found to be unstable in the HIRES stainless-steel canisters independent of ozone levels. Furthermore, growth was observed during storage for some species, namely for HFC-152a, HFC-23, and Halon 1301.

scholarly journals Stability of Halocarbons in Whole Air Samples from the Upper Troposphere and Lowermost Stratosphere

2019 ◽  
Author(s):  
Tanja J. Schuck ◽  
Ann-Katrin Blank ◽  
Elisa Rittmeier ◽  
Jonathan Williams ◽  
Carl A. M. Brenninkmeijer ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Storage Time ◽  
Ambient Air ◽  
Halogenated Hydrocarbons ◽  
Sampling Unit ◽  
Air Samples ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Stable Conditions ◽  
And Storage

Abstract. Measurements of halogenated hydrocarbons in ambient air frequently rely on canister sampling followed by offline laboratory analysis. This allows for a large number of compounds to be analysed under stable conditions, maximising measurement precision. However, individual compounds might be affected during sampling and storage of canister samples. In order to assess halocarbon stability in whole air samples from the upper troposphere and lowermost stratosphere, we performed stability tests using the air sampling unit High REsolution Sampler (HIRES) which is part of the CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) instrument package. HIRES holds 88 light-weight stainless steel cylinders that are pressurized in flight to 4.5 bar using metal bellows pumps. The HIRES sampling unit was first deployed in 2010, but has up to now not been used for regular halocarbon analysis with exception of chloromethane. The sample collection unit was tested for sampling and storage effects of 28 halogenated compounds. The focus was on compound stability in the stainless steel canisters during storage of up to five weeks and on the influence of ozone, since flights take place in the upper troposphere and lowermost stratosphere with ozone mixing ratios of up to several hundred ppbV. Most of the investigated (hydro)chlorofluorocarbons and long-lived hydrofluorocarbons were found to be stable over a storage time of up to five weeks and were unaltered by ozone being present during pressurization. Some compounds such as for example dichloromethane, trichloromethane and tetrachloroethene started to decrease in the canisters after a storage time of more than two weeks or exhibited lowered mixing ratios in samples pressurized with ozone present. Few compounds such as for example tetrachloromethane and tribromomethane were found to be not stable in the HIRES stainless-steel canisters independent of ozone levels. Also growth was observed during storage for some species, namely for HFC-152a, HFC-23, and Halon-1301.

scholarly journals Analytical system for stable carbon isotope measurements of low molecular weight (C<sub>2</sub>-C<sub>6</sub>) hydrocarbons

2011 ◽  
Vol 4 (6) ◽  
pp. 1161-1175 ◽  
Author(s):  
A. Zuiderweg ◽  
R. Holzinger ◽  
T. Röckmann
Keyword(s):  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Ratio ◽  
Ambient Air ◽  
Automated System ◽  
Stable Carbon ◽  
Inlet System ◽  
Air Samples ◽  
Amount Of Substance ◽  
Mixing Ratios

Abstract. We present setup, testing and initial results from a new automated system for stable carbon isotope ratio measurements on C2 to C6 atmospheric hydrocarbons. The inlet system allows analysis of trace gases from air samples ranging from a few liters for urban samples and samples with high mixing ratios, to many tens of liters for samples from remote unpolluted regions with very low mixing ratios. The centerpiece of the sample preparation is the separation trap, which is used to separate CO2 and methane from the compounds of interest. The main features of the system are (i) the capability to sample up to 300 l of air, (ii) long term (since May 2009) operational δ13C accuracy levels in the range 0.3–0.8 ‰ (1-σ), and (iii) detection limits of order 1.5–2.5 ngC (collected amount of substance) for all reported compounds. The first application of this system was the analysis of 21 ambient air samples taken during 48 h in August 2009 in Utrecht, the Netherlands. Results obtained are generally in good agreement with those from similar urban ambient air studies. Short sample intervals allowed by the design of the instrument help to illustrate the complex diurnal behavior of hydrocarbons in an urban environment, where diverse sources, dynamical processes, and chemical reactions are present.

scholarly journals Analysis of non-methane hydrocarbons in air samples collected aboard the CARIBIC passenger aircraft

2009 ◽  
Vol 2 (5) ◽  
pp. 2377-2401 ◽  
Author(s):  
A. K. Baker ◽  
F. Slemr ◽  
C. A. M. Brenninkmeijer
Keyword(s):  
Monitoring Program ◽  
Atmospheric Measurements ◽  
Air Samples ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Civil Aircraft ◽  
Long Term Monitoring ◽  
Passenger Aircraft ◽  
Term Monitoring

Abstract. The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) is a long-term monitoring program making regular atmospheric measurements from an instrument container installed monthly aboard a passenger aircraft. Typical cruising altitudes of the aircraft allow for the study of the free troposphere and the extra-tropical upper troposphere as well as the lowermost stratosphere. CARIBIC measurements include a number of real time analyses as well as the collection of aerosol and whole air samples. These whole air samples are analyzed post-flight for a suite of trace gases, which includes non-methane hydrocarbons (NMHC). The NMHC measurement system and its analytical performance are described here. Precision was found to vary slightly by compound, and is less than 2% for the C2–C6 alkanes and ethyne, and between 1 and 6% for C7–C8 alkanes and aromatic compounds. Preliminary results from participation in a Global Atmospheric Watch (WMO) VOC audit indicate accuracies within the precision of the system. Limits of detection are 1 pptv for most compounds, and up to 3 pptv for some aromatics. These are sufficiently low to measure mixing ratios typically observed in the upper troposphere and lowermost stratosphere for the longer-lived NMHC, however, in air samples from these regions many of the compounds with shorter lifetimes (<5 d) were frequently below the detection limit. Observed NMHC concentrations span many orders of magnitude, dependent on atmospheric region and air mass history, with concentrations typically decreasing with shorter chemical lifetimes.

scholarly journals Analysis of non-methane hydrocarbons in air samples collected aboard the CARIBIC passenger aircraft

2010 ◽  
Vol 3 (1) ◽  
pp. 311-321 ◽  
Author(s):  
A. K. Baker ◽  
F. Slemr ◽  
C. A. M. Brenninkmeijer
Keyword(s):  
Monitoring Program ◽  
Atmospheric Measurements ◽  
Air Samples ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Civil Aircraft ◽  
Long Term Monitoring ◽  
Passenger Aircraft ◽  
Term Monitoring

Abstract. The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) is a long-term monitoring program making regular atmospheric measurements from an instrument container installed monthly aboard a passenger aircraft. Typical cruising altitudes of the aircraft allow for the study of the free troposphere and the extra-tropical upper troposphere as well as the lowermost stratosphere. CARIBIC measurements include a number of real time analyses as well as the collection of aerosol and whole air samples. These whole air samples are analyzed post-flight for a suite of trace gases, which includes non-methane hydrocarbons (NMHC). The NMHC measurement system and its analytical performance are described here. Precision was found to vary slightly by compound, and is less than 2% for the C2–C6 alkanes and ethyne, and between 1% and 6% for C7–C8 alkanes and aromatic compounds. Preliminary results from participation in a Global Atmospheric Watch (WMO) VOC audit indicate accuracies within the precision of the system. Limits of detection are 1 pptv for most compounds, and up to 3 pptv for some aromatics. These are sufficiently low to measure mixing ratios typically observed in the upper troposphere and lowermost stratosphere for the longer-lived NMHC, however, in air samples from these regions many of the compounds with shorter lifetimes (<5 days) were frequently below the detection limit. Observed NMHC concentrations span several orders of magnitude, dependent on atmospheric region and air mass history, with concentrations typically decreasing with shorter chemical lifetimes.

scholarly journals Bottle Aging and Storage of Wines: A Review

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 713
Author(s):  
Javier Echave ◽  
Marta Barral ◽  
Maria Fraga-Corral ◽  
Miguel A. Prieto ◽  
Jesus Simal-Gandara
Keyword(s):  
Storage Time ◽  
Alcoholic Fermentation ◽  
Alcoholic Beverage ◽  
Storage Conditions ◽  
Sulfur Oxide ◽  
Wine Quality ◽  
Complex Chemical ◽  
Stable Conditions ◽  
Bottle Aging ◽  
And Storage

Wine is perhaps the most ancient and popular alcoholic beverage worldwide. Winemaking practices involve careful vineyard management alongside controlled alcoholic fermentation and potential aging of the wine in barrels. Afterwards, the wine is placed in bottles and stored or distributed in retail. Yet, it is considered that wine achieves its optimum properties after a certain storage time in the bottle. The main outcome of bottle storage is a decrease of astringency and bitterness, improvement of aroma and a lighter and more stable color. This is due to a series of complex chemical changes of its components revolving around the minimized and controlled passage of oxygen into the bottle. For this matter, antioxidants like sulfur oxide are added to avoid excessive oxidation and consequent degradation of the wine. In the same sense, bottles must be closed with appropriate stoppers and stored in adequate, stable conditions, as the wine may develop unappealing color, aromas and flavors otherwise. In this review, features of bottle aging, relevance of stoppers, involved chemical reactions and storage conditions affecting wine quality will be addressed.

scholarly journals Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere

2010 ◽  
Vol 10 (13) ◽  
pp. 5903-5910 ◽  
Author(s):  
J. C. Laube ◽  
P. Martinerie ◽  
E. Witrant ◽  
T. Blunier ◽  
J. Schwander ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Altitude ◽  
Bottom Up ◽  
Present Evidence ◽  
Air Samples ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
History Of ◽  
Global Emissions

Abstract. We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in air samples originating from remote regions of the atmosphere and present evidence for its accelerating growth. Observed mixing ratios ranged from below 0.01 ppt in deep firn air to 0.59 ppt in the current northern mid-latitudinal upper troposphere. Firn air samples collected in Greenland were used to reconstruct a history of atmospheric abundance. Year-on-year increases were deduced, with acceleration in the growth rate from 0.029 ppt per year in 2000 to 0.056 ppt per year in 2007. Upper tropospheric air samples provide evidence for a continuing growth until late 2009. Furthermore we calculated a stratospheric lifetime of 370 years from measurements of air samples collected on board high altitude aircraft and balloons. Emission estimates were determined from the reconstructed atmospheric trend and suggest that current "bottom-up" estimates of global emissions for 2005 are too high by a factor of three.

scholarly journals Rapid growth of HFC-227ea (1,1,1,2,3,3,3-Heptafluoropropane) in the atmosphere

2010 ◽  
Vol 10 (3) ◽  
pp. 7675-7697
Author(s):  
J. C. Laube ◽  
P. Martinerie ◽  
E. Witrant ◽  
T. Blunier ◽  
J. Schwander ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Altitude ◽  
Rapid Growth ◽  
Bottom Up ◽  
Present Evidence ◽  
Air Samples ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
History Of ◽  
Global Emissions

Abstract. We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in remote regions of the atmosphere and present evidence for its rapid growth. Observed mixing ratios ranged from below 0.01 ppt in deep firn air to 0.59 ppt in the northern mid-latitudinal upper troposphere. Firn air samples collected in Greenland were used to reconstruct a history of atmospheric abundance. Year-on-year increases were deduced, with acceleration in the growth rate from 0.026 ppt per year in 2000 to 0.057 ppt per year in 2007. Upper tropospheric air samples provide evidence for a continuing growth until late 2009. Furthermore we calculated a stratospheric lifetime of 370 years from measurements of air samples collected on board high altitude aircraft and balloons. Emission estimates were determined from the reconstructed atmospheric trend and suggest that current "bottom-up" estimates of global emissions for 2005 are too high by more than a factor of three.

Electron Microscopic Characterization and Quantitation of Air Borne Particulate Matter with Special Emphasis on Asbestos

1972 ◽  
Vol 30 ◽  
pp. 356-357
Author(s):  
Peter K. Mueller ◽  
Glenn R. Smith ◽  
Leslie M Carpenter ◽  
Ronald L. Stanley
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Ambient Air ◽  
Quality Standard ◽  
Primary Objective ◽  
Cellulose Ester ◽  
Main Concept ◽  
Electron Microscopic ◽  
Air Samples ◽  
Diffraction Patterns

At the present time the primary objective of the electron microscopy group of the Air and Industrial Hygiene Laboratory is the development of a method suitable for use in establishing an air quality standard for asbestos in ambient air and for use in its surveillance. The main concept and thrust of our approach for the development of this method is to obtain a true picture of fiber occurrence as a function of particle size and asbestos type utilizing light and electron microscopy.We have now available an electron micrographic atlas of all asbestos types including selected area diffraction patterns and examples of fibers isolated from air samples. Several alternative approaches for measuring asbestos in ambient air have been developed and/or evaluated. Our experiences in this regard will be described. The most promising method involves: 1) taking air samples on cellulose ester membrane filters with a nominal pore size of 0.8 micron; 2) ashing in a low temperature oxygen plasma for several hours;

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