scholarly journals Compilation and evaluation of gas-phase diffusion coefficients of inorganic reactive trace gases in the atmosphere

2014 ◽  
Vol 14 (10) ◽  
pp. 15645-15682 ◽  
Author(s):  
M. J. Tang ◽  
R. A. Cox ◽  
M. Kalberer
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Diffusion Coefficients ◽  
Trace Gases ◽  
Empirical Method ◽  
Phase Diffusion ◽  
Reactive Trace Gases ◽  
Pressure Independent ◽  
Semi Empirical ◽  
First Time

Abstract. Diffusion of gas molecules to the surface is the first step for all gas-surface reactions. Gas phase diffusion can influence and sometimes even limit the overall rates of these reactions; however, there is no database of the gas phase diffusion coefficients of atmospheric reactive trace gases. Here we compile and evaluate, for the first time, the diffusivities (pressure-independent diffusion coefficients) of atmospheric inorganic reactive trace gases reported in the literature. The measured diffusivities are then compared with estimated values using a semi-empirical method developed by Fuller et al. (1966). The diffusivities estimated using Fuller's method are typically found to be in good agreement with the measured values within ±30%, and therefore Fuller's method can be used to estimate the diffusivities of trace gases for which experimental data are not available. The two experimental methods used in the atmospheric chemistry community to measure the gas phase diffusion coefficients are also discussed.

scholarly journals Compilation and evaluation of gas phase diffusion coefficients of reactive trace gases in the atmosphere: volume 1. Inorganic compounds

2014 ◽  
Vol 14 (17) ◽  
pp. 9233-9247 ◽  
Author(s):  
M. J. Tang ◽  
R. A. Cox ◽  
M. Kalberer
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Diffusion Coefficients ◽  
Inorganic Compounds ◽  
Trace Gases ◽  
Empirical Method ◽  
Phase Diffusion ◽  
Reactive Trace Gases ◽  
Pressure Independent ◽  
Semi Empirical

Abstract. Diffusion of gas molecules to the surface is the first step for all gas–surface reactions. Gas phase diffusion can influence and sometimes even limit the overall rates of these reactions; however, there is no database of the gas phase diffusion coefficients of atmospheric reactive trace gases. Here we compile and evaluate, for the first time, the diffusivities (pressure-independent diffusion coefficients) of atmospheric inorganic reactive trace gases reported in the literature. The measured diffusivities are then compared with estimated values using a semi-empirical method developed by Fuller et al. (1966). The diffusivities estimated using Fuller's method are typically found to be in good agreement with the measured values within ±30%, and therefore Fuller's method can be used to estimate the diffusivities of trace gases for which experimental data are not available. The two experimental methods used in the atmospheric chemistry community to measure the gas phase diffusion coefficients are also discussed. A different version of this compilation/evaluation, which will be updated when new data become available, is uploaded online (https://sites.google.com/site/mingjintang/home/diffusion).

scholarly journals Compilation and evaluation of gas phase diffusion coefficients of halogenated organic compounds

2018 ◽  
Vol 5 (7) ◽  
pp. 171936 ◽  
Author(s):  
Wenjun Gu ◽  
Peng Cheng ◽  
Mingjin Tang
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Input Parameter ◽  
Empirical Method ◽  
Trace Gas ◽  
Temperature And Pressure ◽  
Organic Halogens ◽  
Semi Empirical ◽  
Method Show ◽  
Good Agreement

Organic halogens are of great environmental and climatic concern. In this work, we have compiled their gas phase diffusivities (pressure-normalized diffusion coefficients) in a variety of bath gases experimentally measured by previous studies. It is found that diffusivities estimated using Fuller's semi-empirical method agree very well with measured values for organic halogens. In addition, we find that at a given temperature and pressure, different molecules exhibit very similar mean free paths in the same bath gas, and then propose a method to estimate mean free paths in different bath gases. For example, the pressure-normalized mean free paths are estimated to be 90, 350, 90, 80, 120 nm atm in air (and N 2 /O 2 ), He, argon, CO 2 and CH 4 , respectively, with estimated errors of around ±25%. A generic method, which requires less input parameter than Fuller's method, is proposed to calculate gas phase diffusivities. We find that gas phase diffusivities in He (and air as well) calculated using our method show fairly good agreement with those measured experimentally and estimated using Fuller's method. Our method is particularly useful for the estimation of gas phase diffusivities when the trace gas contains atoms whose diffusion volumes are not known.

scholarly journals Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method

2020 ◽  
Vol 20 (6) ◽  
pp. 3669-3682 ◽  
Author(s):  
Stefan Langenberg ◽  
Torsten Carstens ◽  
Dirk Hupperich ◽  
Silke Schweighoefer ◽  
Ulrich Schurath
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Trace Gases ◽  
Heterogeneous Reactions ◽  
Viscosity Data ◽  
Atmospheric Conditions ◽  
Binary Diffusion ◽  
Phase Diffusion ◽  
Flow Method ◽  
Binary Diffusion Coefficients

Abstract. Gas-phase diffusion is the first step for all heterogeneous reactions under atmospheric conditions. Knowledge of binary diffusion coefficients is important for the interpretation of laboratory studies regarding heterogeneous trace gas uptake and reactions. Only for stable, nonreactive and nonpolar gases do well-established models for the estimation of diffusion coefficients from viscosity data exist. Therefore, we have used two complementary methods for the measurement of binary diffusion coefficients in the temperature range of 200 to 300 K: the arrested flow method is best suited for unstable gases, and the twin tube method is best suited for stable but adsorbing trace gases. Both methods were validated by the measurement of the diffusion coefficients of methane and ethane in helium and air as well as nitric oxide in helium. Using the arrested flow method the diffusion coefficients of ozone in air, dinitrogen pentoxide and chlorine nitrate in helium, and nitrogen were measured. The twin tube method was used for the measurement of the diffusion coefficient of nitrogen dioxide and dinitrogen tetroxide in helium and nitrogen.

scholarly journals Technical note: Determination of binary gas phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – Arrested Flow and Twin Tube method

2019 ◽  
Author(s):  
Stefan Langenberg ◽  
Torsten Carstens ◽  
Dirk Hupperich ◽  
Silke Schweighoefer ◽  
Ulrich Schurath
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Trace Gases ◽  
Heterogeneous Reactions ◽  
Viscosity Data ◽  
Atmospheric Conditions ◽  
Binary Diffusion ◽  
Phase Diffusion ◽  
Flow Method ◽  
Binary Diffusion Coefficients

Abstract. Gas phase diffusion is the first step for all heterogeneous reactions under atmospheric conditions. Knowledge of binary diffusion coefficients is important for the interpretation of laboratory studies regarding heterogeneous trace gas uptake and reactions. Only for stable, nonreactive and non polar gases well-established models for the estimation of diffusion coefficients from viscosity data do exist. Therefore, we have used two complementary methods for the measurement of binary diffusion coefficients in the temperature range of 200 K to 300 K: the arrested flow method is best suited for unstable gases and the twin tube method is best suited for stable but adsorbing trace gases. Both methods were validated by measurement of diffusion coefficients of methane and ethane in helium and air and nitric oxide in helium. Using the arrested flow method the diffusion coefficients of ozone in air, dinitrogen pentoxide and chlorine nitrate in helium and nitrogen were measured. The twin tube method was used for the measurement of the diffusion coefficient of nitrogen dioxide and dinitrogen tetroxide in helium and nitrogen.

NEW METHOD FOR PREDICTION OF BINARY GAS-PHASE DIFFUSION COEFFICIENTS

1966 ◽  
Vol 58 (5) ◽  
pp. 18-27 ◽  
Author(s):  
Edward N. Fuller ◽  
Paul D. Schettler ◽  
J. Calvin. Giddings
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
New Method ◽  
Phase Diffusion

scholarly journals Diffusion of volatile organics through porous snow: impact of surface adsorption and grain boundaries

2013 ◽  
Vol 13 (14) ◽  
pp. 6727-6739 ◽  
Author(s):  
T. Bartels-Rausch ◽  
S. N. Wren ◽  
S. Schreiber ◽  
F. Riche ◽  
M. Schneebeli ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Gas Phase ◽  
Trace Gases ◽  
Snow Sample ◽  
Volatile Organics ◽  
Thin Sections ◽  
Phase Diffusion ◽  
Surface Snow ◽  
Partitioning Coefficients ◽  
Diffusion Profiles

Abstract. Release of trace gases from surface snow on earth drives atmospheric chemistry, especially in the polar regions. The gas-phase diffusion of methanol and of acetone through the interstitial air of snow was investigated in a well-controlled laboratory study in the temperature range of 223 to 263 K. The aim of this study was to evaluate how the structure of the snowpack, the interaction of the trace gases with the snow surface, and the grain boundaries influence the diffusion on timescales up to 1 h. The diffusive loss of these two volatile organics into packed snow samples was measured using a chemical ionization mass spectrometer. The structure of the snow was analysed by means of X-ray-computed micro-tomography. The observed diffusion profiles could be well described based on gas-phase diffusion and the known structure of the snow sample at temperatures ≥ 253 K. At colder temperatures, surface interactions start to dominate the diffusive transport. Parameterizing these interactions in terms of adsorption to the solid ice surface, i.e. using temperature-dependent air–ice partitioning coefficients, better described the observed diffusion profiles than the use of air–liquid partitioning coefficients. No changes in the diffusive fluxes were observed by increasing the number of grain boundaries in the snow sample by a factor of 7, indicating that for these volatile organic trace gases, uptake into grain boundaries does not play a role on the timescale of diffusion through porous surface snow. For this, a snow sample with an artificially high amount of ice grains was produced and the grain boundary surface measured using thin sections. In conclusion, we have shown that the diffusivity can be predicted when the structure of the snowpack and the partitioning of the trace gas to solid ice is known.

scholarly journals Diffusion of volatile organics through porous snow: impact of surface adsorption and grain boundaries

2013 ◽  
Vol 13 (3) ◽  
pp. 6131-6164 ◽  
Author(s):  
T. Bartels-Rausch ◽  
S. N. Wren ◽  
S. Schreiber ◽  
F. Riche ◽  
M. Schneebeli ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Gas Phase ◽  
Trace Gases ◽  
Ionization Mass ◽  
Snow Sample ◽  
Volatile Organics ◽  
Phase Diffusion ◽  
Surface Snow ◽  
Partitioning Coefficients ◽  
Diffusion Profiles

Abstract. Release of trace gases from surface snow on Earth drives atmospheric chemistry, especially in the polar regions. The gas-phase diffusion of methanol and of acetone through the interstitial air of snow was investigated in a well-controlled laboratory study in the temperature range of 223 to 263 K. The aim of this study was to evaluate how the structure of the snowpack, the interaction of the trace gases with the snow surface, and the grain boundaries influence the diffusion on timescales up to 1 h. The diffusive loss of these two volatile organics into packed snow samples was measured using a chemical ionization mass spectrometer. The structure of the snow was analyzed by means of X-ray computed micro-tomography. The observed diffusion profiles could be well described based on gas-phase diffusion and the known structure of the snow sample at temperatures ≥ 253 K. At colder temperatures surface interactions start to dominate the diffusive transport. Parameterizing these interactions in terms of adsorption to the solid ice surface, i.e. using temperature dependent air–ice partitioning coefficients, better described the observed diffusion profiles than the use of air–liquid partitioning coefficients. No changes in the diffusive fluxes were observed by increasing the number of grain boundaries in the snow sample by a factor of 7, indicating that for these volatile organic trace gases, uptake into grain boundaries does not play a role on the timescale of diffusion through porous surface snow. In conclusion, we have shown that the diffusivity can be predicted when the structure of the snowpack and the partitioning of the trace gas to solid ice is known.

scholarly journals Understanding the influence of combustion on atmospheric CO<sub>2</sub> over Europe by using satellite observations of CO<sub>2</sub> and reactive trace gases

2021 ◽  
Author(s):  
Mehliyar Sadiq ◽  
Paul I. Palmer ◽  
Mark F. Lunt ◽  
Liang Feng ◽  
Ingrid Super ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Carbon Dioxide ◽  
Transport Model ◽  
Trace Gases ◽  
Satellite Observations ◽  
Secondary Source ◽  
Combustion Emissions ◽  
Full Complement ◽  
Reactive Trace Gases ◽  
Carbon Dioxide Co2

Abstract. We assess how nitrogen oxides (NOx = NO + NO2), carbon monoxide (CO) and formaldehyde (HCHO) can be used as proxies to determine the combustion contribution to atmospheric carbon dioxide (CO2) using satellite observations. We focus our analysis on 2018 when there is a full complement of column data from the TROPOspheric Monitoring Instrument (NO2, CO, and HCHO) and the Orbiting Carbon Observatory-2 (CO2). We use the nested GEOS-Chem atmospheric chemistry model to relate high-resolution emission inventories over Europe to these atmospheric data, taking into account scene-dependent averaging kernels. We find that that NO2 and CO are the better candidates to identify incomplete combustion and fingerprints of different combustion sectors, but both have their own challenges associated with properly describing their atmospheric chemistry. The secondary source of HCHO from oxidation of biogenic volatile organic compounds, particularly over southern European countries, compromises its use as a proxy for combustion emissions. We find a weak positive correlation between the CO : CO2 inventory ratio and observed column enhancements of ΔCO : ΔCO2 (R < 0.2), suggesting some consistency and linearity in CO chemistry and transport. However, we find a stronger negative correlation between the NOx : CO2 inventory ratio and observed column enhancements of ΔNO2 :ΔCO2 (R < 0.50), driven by non-linear photochemistry. Both of these observed ratios are described well by the GEOS-Chem atmospheric chemistry transport model, providing confidence of the quality of the emission inventory and that the model is a useful tool for interpreting these tracer-tracer ratios. Our results also provide some confidence in our ability to develop a robust method to infer combustion CO2 emission estimates using satellite observations of reactive trace gases that have up until now mostly been used to study surface air quality.

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