Nitrous oxide atmospheric composition

The interstitial air trapped during this process preserves a largely unaltered record of the composition of past atmospheres on time scales as short as decades and as long as several hundred thousand years. Such records have provided critical information about past variations in carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), and the isotopic composition of some of these trace species. In addition, studies of the major elements of air nitrogen, oxygen, and argon, and their isotopic composition, have contributed... 

Stein LY, Yung YL (2003) Production, isotopic composition, and atmospheric fate of biologically produced nitrous oxide. Ann Rev Earth Planet Sci 31 329-356 Stem LA, Chamberlain CP, Reynolds RC, Johnson CD (1997) Oxygen isotope evidence of climate change from pedogenic clay minerals in the Himalayan molasse. Geochim Cosmochim Acta 61 731-744... 

Above, we described the solar resource at the top of the atmosphere. The atmosphere acts as a continuously variable filter for the ETR radiation. The atmosphere has stable components of 78% nitrogen, 21% oxygen, and 1% argon and other "noble" gases. There are also variable components in the atmosphere, such as water vapor (0% to 2% of the total composition), and gases dumped into the atmosphere by manmade and natural process, such as carbon dioxide, (0.035%), methane, and nitrous oxides.6... 

Figure 16.10 (A) Nitrous oxide (N2O) concentrations and isotopic composition for water samples collected at Station ALOHA. [Left] Depth profile of N2O showing a distinct mid-depth maximum of 60 nM coincident with the dissolved oxygen minimum. [Center] N isotope composition of N2O. [Right] 0 isotope composition of N2O. Data from Dore et al. (1998) and B. Popp and J. Dore (unpublished). (B) N2O saturation state, expressed as a percentage of air saturation, for the upper portion of the water column at Station ALOHA during the period September 1992— September 1994. The vertical dashed line indicates equilibrium (100% saturation) with atmospheric N2O. With the exception of one measured value on cruise HOT-45, all determinations indicate significant N2O saturation relative to the atmosphere which implies both a local source and a net ocean-to-air gas flux.From Dore and Karl (1996a).

The maj or environmental concern for nitric acid oxidation of either cyclohexanol or the KA Oil is the emission of the greenhouse gas nitrous oxide, N2O. Theemission factor is estimated to be around 300 kg of N2O per ton of AA indeed, the real value is between 260 and 330 (around 0.75-1.2 mol of N2O per mole of AA), depending on the amount of catalyst used and the KA Oil composition. For a global AA production of 3.0 M-tonyr, the total amount of N2O produced is estimated to be about 0.9 M-tonyr. However, nowadays less than 5% of total emission of N2O into the atmosphere is from anthropogenic origin, and of this 5% only a small fraction is due to AA production, because almost all the AA producers have installed N2O decomposition units. 

At our level in the troposphere, air is a mixture of gases of uniform composition, except for water vapor, which composes l%-3% of the atmosphere by volume, and some of the trace gases, such as pollutant sulfur dioxide. On a dry basis, air is 78.1% (by volume) N2, 21.0% O2, 0.9% argon, and 0.04% carbon dioxide. Trace gases at levels below 0.002% in air include ammonia, carbon monoxide, helium, hydrogen, krypton, methane, neon, nitrogen dioxide, nitrous oxide, ozone, sulfur dioxide, and xenon. 

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