scholarly journals Estimation of the molecular hydrogen soil uptake and traffic emissions at a suburban site near Paris through hydrogen, carbon monoxide, and radon-222 semicontinuous measurements

2009 ◽  
Vol 114 (D18) ◽  
Author(s):  
C. Yver ◽  
M. Schmidt ◽  
P. Bousquet ◽  
W. Zahorowski ◽  
M. Ramonet
Keyword(s):  
Carbon Monoxide ◽  
Molecular Hydrogen ◽  
Traffic Emissions ◽  
Soil Uptake ◽  
Suburban Site

Strahlenchemie von Alkoholen XVII

1972 ◽  
Vol 27 (1) ◽  
pp. 41-46 ◽  
Author(s):  
C. v. Sonntag
Keyword(s):  
Carbon Monoxide ◽  
Molecular Hydrogen ◽  
Reaction Scheme ◽  
Quantum Yields ◽  
Effect Of Water ◽  
Formed Hydrogen

In the 185 nm photolysis of liquid O2-free isopropanol the following products (quantum yields) are formed: hydrogen (0.75), acetone (0.72), pinacol (0.036), methane (0.046), acetaldehyde (0.04), propane (0.02β), ane (0.0023) and carbon monoxide (0.0015). A detailed reaction scheme is proposed. The major primary processes are the formation of H-atoms by homolytic scission of the O —H-bond (61 — 69%), elimination of molecular hydrogen (21%) and molecular methane (5%). Φ(Η2) is strongly decreased by adding water which does not absorb an appreciable portion of the 185 nm light in the mixtures down to 1 mole/l isopropanol (Φ(Η2) =0.21). In contrast to the strong effect of water there is no effect on Φ(Η2) by diluting isopropanol with n-hexane. From experiments with isopropanol-OD and 2-deutero-isopropanol it is tentatively concluded that H-atoms stemming from the O—H-group of the alcohol are to about 65% the precursors of the hydrogen in these mixtures.

Molecular hydrogen and carbon monoxide in seawater in an area adjacent to Kuroshio and Honshu Island in Japan

2014 ◽  
Vol 164 ◽  
pp. 75-83 ◽  
Author(s):  
Shinsuke Kawagucci ◽  
Taku Narita ◽  
Hajime Obata ◽  
Hiroshi Ogawa ◽  
Toshitaka Gamo
Keyword(s):  
Carbon Monoxide ◽  
Molecular Hydrogen ◽  
Honshu Island

scholarly journals The impact of soil uptake on the global distribution of molecular hydrogen: chemical transport model simulation

2011 ◽  
Vol 11 (2) ◽  
pp. 4059-4103 ◽  
Author(s):  
H. Yashiro ◽  
K. Sudo ◽  
S. Yonemura ◽  
M. Takigawa
Keyword(s):  
Biological Activity ◽  
Seasonal Variation ◽  
Biomass Burning ◽  
Arid Region ◽  
Molecular Hydrogen ◽  
Deposition Velocity ◽  
Soil Surface ◽  
Soil Uptake ◽  
Semi Arid Region ◽  
Semi Arid

Abstract. The molecular hydrogen (H2) in the troposphere is highly influenced by the strength of H2 uptake by the terrestrial soil surface. The global distribution of H2 and its uptake by the soil are simulated by using a model called CHemical AGCM for Study of Environment and Radiative forcing (CHASER), which incorporates a 2-layered soil diffusion/uptake process component. The simulated distribution of deposition velocity over land reflects regional climate and has a global average of 3.3 × 10−2 cm s−1. In the region north of 30° N, the amount of soil uptake increases, particularly in the summer. However, the increase in the uptake becomes smaller in the winter season due to snow cover and a reduction in the biological activity at low temperatures. In the temperate and humid regions in the mid- and low-latitudes, the uptake is mostly influenced by the soil air ratio, which controls the gas diffusivity in the soil. In the semi-arid region, water stress and high temperature contribute to the reduction of biological activity, as well as to the seasonal variation in the deposition velocity. The comparison with the observations shows that the model reproduces both the distribution and seasonal variation of H2 relatively well. The global burden and tropospheric lifetime are 150 Tg and 2.0 yr, respectively. The seasonal variation of H2 in the northern high latitude is mainly controlled by the large seasonal change in soil uptake. In the Southern Hemisphere, the seasonal change in the net chemical production and inter-hemispheric transport are the dominant cause of the seasonal cycle. Large biomass burning impacts the magnitude of seasonal variation mainly in the tropics and subtropics. Both observation and model show large inter-annual variation, especially for the period 1997–1998, associated with the large biomass burning in tropics and northern high-latitudes. The soil uptake shows relatively small inter-annual variability compared to the signal from biomass burning. We note that the thickness of biologically inactive layer near the soil surface and the uptake flux in semi-arid region is important for the current and future budget of atmospheric H2.

Sign in / Sign up

Export Citation Format

Share Document