Carbon monoxide anthropogenic

A substantial portion of fhe gas and vapors emitted to the atmosphere in appreciable quantity from anthropogenic sources tends to be relatively simple in chemical structure carbon dioxide, carbon monoxide, sulfur dioxide, and nitric oxide from combustion processes hydrogen sulfide, ammonia, hydrogen chloride, and hydrogen fluoride from industrial processes. The solvents and gasoline fractions that evaporate are alkanes, alkenes, and aromatics with relatively simple structures. In addition, more complex... 

The total amount of carbon monoxide in the atmosphere has been estimated at about 3.06 million short tons (2.78 million metric tons). Of this, about half (1.438 million metric tons) is produced naturally and about half (1.350 million metric tons) through anthropogenic (human-made) sources. Naturally occurring carbon monoxide is not generally regarded as an environmental problem because it is so widely spread at very low concentrations (about 0.1 ppmv [parts per million by volume]) throughout the atmosphere. 

The most important single source of anthropogenic carbon monoxide in the United States is motor vehicles. Cars and trucks account... 

The contribution of savannah fires exceeds 40% of the global level of biomass burning as a result of which the atmosphere receives minor gas components, such as non-methane hydrocarbons, carbon monoxide, methane, etc., as well as aerosols. According to available estimates for the period 1975-1980, 40%-70% of savannahs were burnt every year, about 6% of such fires took place in Africa. In 1990 about 2 1091 of vegetable biomass were burnt, and as a result 145TgCO got into the atmosphere, which constituted about 30% of anthropogenic CO emissions. 

On the basis of ratios of C and C present in carbon dioxide, Weinstock (250) estimated a carbon monoxide lifetime of 0.1 year. This was more than an order of magnitude less than previous estimates of Bates and Witherspoon (12) and Robinson and Robbins (214), which were based on calculations of the anthropogenic source of carbon monoxide. Weinstock (250) suggested that if a sufficient concentration of hydroxyl radical were available, the oxidation of carbon monoxide by hydroxyl radical, first proposed by Bates and Witherspoon (12) for the stratosphere, would provide the rapid loss mechanism for carbon monoxide that appeared necessary. By extension of previous stratospheric models of Hunt (104), Leovy (150), Nicolet (180), and others, Levy (152) demonstrated that a large source of hydroxyl radical, the oxidation of water by metastable atomic oxygen, which was itself produced by the photolysis of ozone, existed in the troposphere and that a chain reaction involving the hydroxyl and hydroperoxyl radicals would rapidly oxidize both carbon monoxide and methane. It was then pointed out that all the loss paths for the formaldehyde produced in the methane oxidation led to the production of carbon monoxide [McConnell, McElroy, and Wofsy (171) and Levy (153)1-Similar chain mechanisms were shown to provide tropospheric... 

There are over 70 alcohols in the atmosphere as a result of biogenic and anthropogenic emissions [67]. For example methanol and ethanol [68-70] have been used as fuels additives to reduce automobile emissions of carbon monoxide and hydrocarbons [71], in particular ethanol has been used in Brazil as a fuel for over 20 years [72]. 1-Propanol is widely used as a solvent in the manufacturing of different electronic components. The high volatility of these compounds causes their relative abundance in the troposphere and makes it relevant to determine their degradation pathways. During daytime the major loss process for alcohols is their reaction with OH radicals [68]. Accordingly, several experimental [69,70,73-84] and theoretical [85-88] kinetic studies of alcohols -F OH reactions have been performed. 

The atmosphere is an important conveyor belt for many pollutants. The atmosphere reacts most sensitively to anthropogenic disturbance because proportionally it represents a much smaller reservoir than land and water furthermore, the residence times of many constituents of the atmosphere are smaller than those that occur in the other exchange reservoirs. Water and atmosphere are interdependent systems. Many pollutants, especially precursors of acids and photooxidants, originate directiy or indirecdy from the combustion of fossil fuels. Hydrocarbons, carbon monoxide, and nitrogen oxides released by thermal power plants and, above all by automobile engines, can produce, under the influence of sunlight, ozone and other photooxidants. 

Crutzen PJ, Gidel LT. 1983. A two-dimensional photochemical model of the atmosphere. 2 The tropospheric budgets of the anthropogenic chlorocarbons, carbon monoxide, methane, chloromethane and the effect of various nitrogen oxides sources on the tropospheric ozone. Journal of Geophysical Research... 

Like CH4, carbon monoxide was first optically identified in the atmosphere by Migeotte (1949). It was believed at that time that atmospheric CO was wholly due to anthropogenic sources. However, more recent studies show that carbon monoxide is emitted into the air by many other sources. Furthermore, it became clear that the atmospheric cycle of this trace gas is much more complicated than was thought at the time of its discovery. 

According to the results of measurements carried out in the ocean (Seiler, 1974) the carbon monoxide concentration in near surface marine layers is 5 x 10 s mil 1 on an average. This water concentration would be in equilibrium with a surface air CO level of 2.5 ppm. However, the carbon monoxide concentration in air over the ocean surface is between 0.04 ppm and 0.20 ppm, which means that the ocean water is supersaturated with CO. It follows from these data that the ocean is a CO source, the global strength of which is about six times less than the total anthropogenic emission (Table 7). 

It is important to note that certain cycles can lead to ozone formation this phenomenon is readily observed in the troposphere (see Box 5.4), which is rich in anthropogenic hydrocarbons and nitrogen oxides. In the free troposphere and lower stratosphere, the conversion of NO to NO2 by peroxy radicals (HO2 and CH3O2) produced by the oxidation of methane and carbon monoxide, followed by the photodissociation of NO2 leads to the formation of O3. The complete chains are the following (Crutzen, 1974) ... 

Gasolines with added ethers or alcohols, formulated according to the Federal Clean Air Act to reduce carbon monoxide emissions during winter months. PAHs are a suite of compounds with two or more benzene rings. PAHs are found in many petroleum mixtures, and they are predominantly introduced to the environment through natural and anthropogenic combustion processes. 

Estimates of annual amounts of emissions released into the earth s atmosphere are remarkably different from each other, depending on the choice of balance models [5-24]. For the anthropogenic sources, the following substances may be listed in decreasing order of importance carbon dioxide, carbon monoxide, sulphur oxides, hydrocarbons, nitrogen oxides and liquid and solid particles. A summary of relative contributions of these substances to total emissions of main types of anthropogenic sources is given in Table 5.8. 

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