Nitrogen oxides contribution to acid

Burning fossil fuels can release air pollutants such as carbon dioxide, sulfur oxides, nitrogen oxides, ozone, and particulate matter. Sulfur and nitrogen oxides contribute to acid rain ozone is a component of urban smog, and particulate matter affects respiratory health. In fact, several studies have documented a disturbing correlation between suspended particulate levels and human mortality. It is estimated that air pollution may help cause 500,000 premature deaths and millions of new respiratory illnesses each year. 

Atmospheric pollution caused by SO compounds from the combustion of fossil fuels, O3, CO2, volumetric CH compounds, and NO has become as matter of growing world wide concern in recent years. Nitrogen oxides contribute to acid rain and photochemical smog, and they can cause respiratory problem. Therefore, nitrogen oxides should be controlled and removed from the source in order to keep the earth clean and as-received for our health [1-3]. 

Nitrogen oxide is rapidly oxidized to nitrogen dioxide on exposure to air, a reaction that contributes to acid rain (see Box 10.1) ... 

Methane releases 25% less carbon dioxide per gram than coal, and it emits none of the oxides of nitrogen and sulfur that contribute to acid precipitation. Therefore, using methane in place of other fossil fuels is very desirable. Methane hydrates seem to be an ideal and plentiful pre-packaged source of natural gas. Estimates of the exact amount of methane stored in hydrates suggest there could be... 

Oxides of nitrogen also contribute to the formation of acid deposition. These oxides are formed whenever sufficient heat is generated in a power generating plant or industrial operation to allow the formation of nitric oxide from nitrogen and oxygen ... 

Oxides of nitrogen play a central role in essentially all facets of atmospheric chemistry. As we have seen, N02 is key to the formation of tropospheric ozone, contributing to acid deposition (some are toxic to humans and plants), and forming other atmospheric oxidants such as the nitrate radical. In addition, in the stratosphere their chemistry and that of halogens interact closely to control the chain length of ozone-destroying reactions. 

Historically, the major acids believed to contribute to acid deposition in the troposphere have been sulfuric and nitric acids, formed by the oxidation in air of S02 and oxides of nitrogen, respectively. However, there is an increasing recognition that organic acids may contribute significantly to the total acid burden and indeed may represent the major acidic species even in polluted urban environments. In addition, since nitrous acid (HONO) is formed whenever N02 and water are present (see Chapter 7.B.3), its contribution to the total acidity, particularly to indoor air environments, has become of interest and concern. 

Nitrogen Oxides. Nitrogen dioxide (NO2), a gas found in photochemical smog, is also a pulmonary irritant and is known to lead to pulmonary edema and hemorrhage. The main issue of concern is its contribution to the formation of photochemical smog and ozone, although nitrogen oxides also contribute to acid deposition. 

CS Explain why gaseous nitrogen oxides emitted by automobiles and industries contribute to acid rain. Write balanced chemical reactions to back up your ideas. You may need to look up chemical formulas for your products. 

Considerable attention has been given to nitrogen oxides (and sulfur oxides) in the atmosphere because of their contributions to acid rain. Several studies suggest that different isotopic techniques can be used to differentiate among different types of atmospherically derived nitrate and ammonium. For example, Heaton (1990) found that derived from vehicle exhaust... 

Initially, fuel sulfur was regulated to reduce emissions of the oxides of sulfur, which contribute to acid rain, ozone, and smog. The recent and stricter round of sulfur specifications, however, are an effort to reduce automobile emissions of the oxides of nitrogen (NO c) and particulate matter (PM). For example, the 15 ppmw diesel sulfur limit follows from the USEPA s parallel program of rule making that seeks to reduce automobile NO and PM emissions by 95% and 90%, respectively, by 2007. Automobile manufacturers are demanding ultra-low-sulfur fuels because only then would their advanced, sulfur-sensitive after-treatment technologies achieve such drastic reductions in NO and PM emissions. 

In the stratosphere, positive ions could contribute to the conversion of nitrogen oxides into nitric acid by the following chain ... 

It is also used as an electron acceptor by microorganisms. Nitrihcation of ammonia N in soil is a source of nitrate. In addition, nonpoint and point source discharges from terrestrial ecosystems can be a major source of nitrate to wetlands and aquatic systems. In the atmosphere, nitrogen oxides can react with photochemically produced free radicals and produce nitric acid, which contributes to acid rain. Nitrate is also a common fertilizer used in agricultural ecosystems. 

Nitric oxide is formed in the combustion of fossil fuels and is present in automobile and power plant exhausts it can also be formed from the action of lightning on atmospheric N2 and O2. In the atmosphere, NO is oxidized to NO2. These gases, often collectively des-—E 2 HNO3 -E NO ignated NO., contribute to acid rain, primarily because NO2 reacts with atmospheric water to form nitric acid. Nitrogen oxides are also believed to be instrumental in the destruction of the Earth s ozone layer (Section 8.8.1). 

This group of compounds is characterized by relatively short atmospheric lifetimes (hours to days). They are best thought of as a group in that NO is the primary source and HNO3 is the primary sink. These compounds are responsible for formation of photochemical smog and contribute to acid precipitation. Two subgroups within this broader class are defined. NOx, is defined as NO -I- NO2 and NOy refers to the sum of all reactive nitrogen oxides. NOy specifically excludes less reactive compounds such as N2O. 

The two radical species NO and NO2 are of great practical importance. Nitrogen dioxide (NO2) is a major pollutant, contributing to acid rain as well as to respiratory illnesses. Nitric oxide (NO) is a ubiquitous signaling molecule in biology. 

Nitrogen oxides play an important role in the photochemistry of the troposphere, controlling the formation of tropospheric O3, affecting the concentration of the hydroxyl radical, and contributing to acid precipitation. Nitrogen dioxide (NO2) is one of the most important reactive nitrogen species its photolysis is the primary source of O3 in the troposphere (see Section 28.6 for further details on the actual chemical processes and rates). 

Contrary to popular belief, acid rain is not a new phenomenon nor does it result solely from industrial pollution. Natural processes—volcanic eruptions and forest fires, for example—produce and release acid particles into the air, and the burning of foresf areas to clear land in Brazil, Africa, and other countries also contributes to acid rain however, the rise in manufacturing that began with the Industrial Revolution literally dwarfs all other contributions to the problem. The main culprits are emissions of sulfur dioxide from the burning of fossil fuels, such as oil and coal, and nitrogen oxide, formed mostly from internal combustion engine emissions, which is readily transformed into nitrogen dioxide. These mix in the atmosphere to form sulfuric acid and nitric acid. 

Nitrogen oxides contribute both to ground level ozone formation and acid deposition in the form of acidic particles, fog, and rain [11]. The major source of NOx is from high-temperature combustion processes of fossil fuels in power plants, vehicles, and airplanes. A potentially very large field of application for high-temperature NOx sensors is for emissions control for next-generation lean-bum engines, where catalytic converters are ineffective [12]. 

One of the atmospheric pollutants that contributes to acid rain is nitrogen dioxide (NO2). A major source of NOi is automobile exhaust. When nitrogen in the air is burned in an internal combustion engine, it is converted to nitric oxide (NO) ... 

Figure 21.21 Mean precipitation pH in the United States in 1994. Most SO2 comes from the midwestem states. Prevailing winds carry the acid droplets formed over the Northeast. Nitrogen oxides also contribute to acid rain formation.

Like CO and SOx, nitrie oxide (NO) and nitrogen dioxide (NO2) are emitted by fired heaters, power plants and FCC regenerators. NOx also damage respiratory tissues and contribute to acid rain. 

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