Nitrogen oxides table

C. Formation and Reduction of Nitrogen Oxides TABLE 1 Structure of Gaseous Nitrogen Compounds -... 

ERA promulgated the basic set of current ambient air-quality standards in April 1971. The specific regulated pollutants were particulates, sulfur dioxide, photochemical oxidants, hydrocarbons, carbon monoxide, and nitrogen oxides. In 1978, lead was added. Table 25-1 enumerates the present standards. 

Human-made sources cover a wide spectrum of chemical and physical activities and are the major contributors to urban air pollution. Air pollutants in the United States pour out from over 10 million vehicles, the refuse of over 250 million people, the generation of billions of kilowatts of electricity, and the production of innumerable products demanded by eveiyday living. Hundreds of millions of tons of air pollutants are generated annu ly in the United States alone. The five main classes of pollutants are particulates, sulfur dioxide, nitrogen oxides, volatile organic compounds, and carbon monoxide. Total emissions in the United States are summarized by source categoiy for the year 1993 in Table 25-10. 

TABLE 25-25 Advantages and Disadvantages of Selective Catalytic Reduction of Nitrogen Oxides... 

The principal components of atmospheric chemical processes are hydrocarbons, oxides of nitrogen, oxides of sulfur, oxygenated hydrocarbons, ozone, and free radical intermediates. Solar radiation plays a crucial role in the generation of free radicals, whereas water vapor and temperature can influence particular chemical pathways. Table 12-4 lists a few of the components of each of these classes. Although more extensive tabulations may be found in "Atmospheric Chemical Compounds" (8), those listed in... 

Effects of given concentrations of nitrogen oxides are listed in Table 5.33 the margin between concentrations that provoke mild symptoms and those proving to be fatal is small. A person with a normal respiratory function may be affected by exposure to as low as 5 ppm diseases such as bronchitis may be aggravated by such exposures. The current 8 hr TWA OES is 3 ppm with an STEL (page 99) of 5 ppm. 

Nitrogen forms several oxides, with oxidation numbers ranging from - -l to +5. All nitrogen oxides are acidic oxides and some are the acid anhydrides of the nitrogen oxoacids (Table 15.2). In atmospheric chemistry, where the oxides play an important two-edged role in both maintaining and polluting the atmosphere, the) are referred to collectively as NO (read nox ). 

Table 19-1 demonstrates that with the exception of water vapor, all of these cycles have been severely perturbed by human activity. Of course, all of these cycles are also linked in many ways. For example, the combustion of fossil fuel has increased the fluxes of carbon, sulfur, and nitrogen oxides to the atmosphere. Denitrification, the production of N2O, is linked with the production of CO2 during respiration and decay. And of course, other important cycles are involved which are not depicted here. Look back at Fig. 17-8, which sums up the climate forcings by the key agents. 

Effects of given concentrations of nitrogen oxides are listed in Table 4.26 the margin... 

Table III. Nitrosating Agents Nitrogen Oxidation State Reference...

In accordance with the production plans (Odisharia et al 1994), the increase of emission rate for nitrogen oxides (NO ) in the area of Bovanenkovo gas exploration in Yamal peninsula will be during 2000-2015 (Figure 7). Emission of sulfur oxide will be practically permanent and will amount to about 470,000 tons per year. These data indicate also the growth of deposition rate for acid forming and eutrophication compounds in comparison with the present period (Table 1). 

Basic rate information permits one to examine these phenomena in detail. Leighton [2], in his excellent book Photochemistry of Air Pollution, gives numerous tables of rates and products of photochemical nitrogen oxide-hydrocarbon reactions in air this early work is followed here to give fundamental insight into the photochemical smog problem. The data in these tables show low rates of photochemical consumption of the saturated hydrocarbons, as compared to the unsaturates, and the absence of aldehydes in the products of the saturated hydrocarbon reactions. These data conform to the relatively low rate of reaction of the saturated hydrocarbons with oxygen atoms and their inertness with respect to ozone. 

TABLE A2 Thermochemical Data of Selected Chemical Compounds Nitrogen oxide (NO), ideal gas, molecular weight = 30.0061... 

Rate constant data for reactions of post-combustion gases including nitrogen oxides, hydrogen chloride, ozone, and sulfur oxides are presented in Tables C8-C11. 

The classes of major primary pollutants that are important in urban areas are listed in Table 2-1. The pollutants most responsible for oxidant formation in the air are the nitrogen oxides, hydrocarbons, aldehydes, and carbon monoxide. The internal-combustion engine is a major source of emission of these primary pollutants, although many stationary sources. 

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