Nitrous emissions

R. A. Reimer and co-workers, paper presented at the 6th International Workshop on Nitrous Oxide Emissions, Turku/Abo, Finland, June 7—9, 1994, 25... 

Quantitative aluminum deterrninations in aluminum and aluminum base alloys is rarely done. The aluminum content is generally inferred as the balance after determining alloying additions and tramp elements. When aluminum is present as an alloying component in alternative alloy systems it is commonly deterrnined by some form of spectroscopy (qv) spark source emission, x-ray fluorescence, plasma emission (both inductively coupled and d-c plasmas), or atomic absorption using a nitrous oxide acetylene flame. 

Two colorimetric methods are recommended for boron analysis. One is the curcumin method, where the sample is acidified and evaporated after addition of curcumin reagent. A red product called rosocyanine remains it is dissolved in 95 wt % ethanol and measured photometrically. Nitrate concentrations >20 mg/L interfere with this method. Another colorimetric method is based upon the reaction between boron and carminic acid in concentrated sulfuric acid to form a bluish-red or blue product. Boron concentrations can also be deterrnined by atomic absorption spectroscopy with a nitrous oxide—acetjiene flame or graphite furnace. Atomic emission with an argon plasma source can also be used for boron measurement. 

Dasch, J. M., Nitrous oxide emissions from vehicles, j. Air Waste Manage. Assoc. 42(1) 32-38 (January 1992). 

In densely populated areas, traffic is responsible for massive exhausts of nitrous oxides, soot, polyaromatic hydrocarbons, and carbon monoxide. Traffic emissions also markedly contribute to the formation of ozone in the lower parts of the atmosphere. In large cities, fine particle exposure causes excess mortality which varies between one and five percent in the general population. Contamination of the ground water reservoirs with organic solvents has caused concern in many countries due to the persistent nature of the pollution. A total exposure assessment that takes into consideration all exposures via all routes is a relatively new concept, the significance of which is rapidly increasing. 

Public concerns about air quality led to the passage of the Clean Air Act in 1970 to amendments to that act in 1977 and 1990. The 1990 amendments contained seven separate titles covering different regula-toiy programs and include requirements to install more advanced pollution control equipment and make other changes in industrial operations to reduce emissions of air pollutants. The 1990 amendments address sulfur dioxide emissions and acid rain deposition, nitrous oxide emissions, ground-level ozone, carbon monoxide emissions, particulate emissions, tail pipe emissions, evaporative emissions, reformulated gasoline, clean-fueled vehicles and fleets, hazardous air pollutants, solid waste incineration, and accidental chemical releases. 

Excess fertilizer and combustion processes also can increase nitrous oxide (NnO) and nitrogen oxides (NOx) in the atmosphere. Nitrous oxide is a powerful greenhouse gas, and nitrogen oxides lead to smog and acid rain. The production of fertilizers requires a great deal of energy. The use of fossil fuels to supply the thermal requirements for fertilizer production further increases emission of nitrogen compounds to the atmosphere. 

Since nitrous oxide, NjO, is a designated "greenhouse" gas, and may contribute to depletion of the ozone layer, its removal from emissions to atmosphere is desirable [1]. However, there are several reports that NjO can be formed at low selectivity as an undesirable by-product of NO+CO conversions during the initial warm-up-from-cold periods in three-way-catalytic (TWC) converters or components thereof [1-3]. TWC s commonly contain Rhodium and Ceria and although N,0 dissociation over RhjO, has been extensively studied [4], the following are among mechanistic possibilities as yet... 

Bouwman, A. F. (1996). Direct emission of nitrous oxide from agricultural soils. Nutr. Cycl. Agroecosyst. 46, 53-70. 

Chianese, D. S., Rotz, C. A., and Richard, T. L. (2009d). Simulation of nitrous oxide emissions from dairy farms to assess greenhouse gas reduction strategies. Trans. ASABE 52, 1325-1335. 

Davidson, E. A., Keller, M., Erickson, H. E., Verchot, L. V., and Veldkamp, E. (2000). Testing a conceptual model of soil emissions of nitrous and nitric oxide. Bioscience 50, 667-680. 

Monteny, G. J., Groenestein, C. M., and Hilhorst, M. A. (2001). Interactions and coupling between emissions of methane and nitrous oxide from animal husbandry. Nutr. Cycl. Agroecosyst. 60,123-132. 

Each greenhouse gas differs in its ability to absorb heat in the atmosphere. HFCs and PFCs are the most heat-absorbent. Methane traps over 21 times more heat per molecule than carbon dioxide, and nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide. Often, estimates of greenhouse gas emissions are presented in units of millions of metric tons of carbon equivalents (MMTCE), which weighs each gas by its GWP value, that is, Global Warming Potential. 

What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions (5). For example, in 1997, the United States emitted about one-fifth of total global greenhouse gases. 

Much later—more than half a century after Carothers invented nylon— scientists at the University of California at San Diego discovered that the production of nylon seemed to contribute a small but significant amount of nitrous oxide to the atmosphere. By that time, it was well known that nitrous oxide, N20, is a potent greenhouse gas and ozone destroyer. Within a month of the discovery s publication in 1991, Du Pont and several other nylon producers announced plans to phase out nitrous oxide emissions within five years. 

Abstract Presently, a growing interest is focused on unregulated emissions of nitrous oxide (N20) from stationary and mobile sources in order to anticipate future restrictive legislations, since N20 exhibits a significant higher global warming power than that of C02. 

Cai Z, Xing G, Yan X, Xu H, Tsuruta H, Yagi K, Minami K. Methane and nitrous oxide emissions from rice paddy fields as affected by nitrogen fertilisers and water management. Plant Soil. 1997 196 7-14. 

Furukawa Y, Inubushi K. Effect of application of iron materials on methane and nitrous oxide emissions from two types of paddy soils. Soil Sd. Plant Nutr. 2004 50 917-924. 

Hou AX, Chen GX, Wang ZP, Van Cleemput O, Patrick Jr WH. Methane and nitrous oxide emissions from a rice field in relation to soil redox and microbiological processes. Soil Sci. Soc. Am. J. 2000 64 2180-2186. 

Simmonds MB, Anders M, Adviento-Borbe MA, van Kessel C, McClung A, Linquist BA. Seasonal methane and nitrous oxide emissions of several rice cultivars in direct-seeded systems. J. Environ. Qual. 2015 44 103-114. 

Fernandez-Luqueno F, Reyes-Varela V, Cervantes-Santiago F, Gomez-Juarez C, San-tillan-Arias A, Dendooven L.Emissions of carbon dioxide, methane and nitrous from soil receiving urban wastewater for maize Zea mays L.) cultivation. Plant Soil. 2010 331 203-215. DOI 10.1007/slll04-009-0246-0... 

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