Fossil fuel combustion, effect

Also, by the very nature of chemical transformations, there are almost always unused chemicals remaining. These chemical leftovers include contaminants in the raw materials, incompletely converted raw materials, unavoidable coproducts, unselective reaction by-products, spent catalysts, and solvents. There have long been efforts to minimize the production of such waste products, and to recover and reuse those that cannot be eliminated. For those that cannot be reused, some different use has been sought, and as a last resort, efforts have been made to safely dispose of whatever remains. The same efforts apply to any leftovers from the production of the energy from the fuels produced or consumed by the processing industries. Of particular immediate and increasing concern are the potential detrimental effects of carbon dioxide emissions to the atmosphere from fossil fuel combustion, as discussed further in Chapters 9 and 10. 

I apply these computational methods to various aspects of the Earth system, including the responses of ocean and atmosphere to the combustion of fossil fuels, the influence of biological activity on the variation of seawater composition between ocean basins, the oxidation-reduction balance of the deep sea, perturbations of the climate system and their effect on surface temperatures, carbon isotopes and the influence of fossil fuel combustion, the effect of evaporation on the composition of seawater, and diagenesis in carbonate sediments. These applications have not been fully developed as research studies rather, they are presented as potentially interesting applications of the computational methods. 

Another problem associated with fossil fuel combustion is the greenhouse effect, which brings up critical environmental concerns. 

Comar CL, Nelson N. 1975. Health effects of fossil fuel combustion products Report of a workshop. Environ Health Perspect 12 149-170. 

Desulphurisation of hydrocarbon fuels has traditionally been carried out primarily as part of the refining and upgrading process. Accordingly by far the most advanced and best understood chemistry and technology is to be found in this area. Prior to the advent of major concern for environmental impact of fossil fuel combustion products relatively little was done to desulphurise hydrocarbon fuels (principally coal) prior to combustion and past effects of large scale consumption of high sulphur coals can still be seen in major industrialised areas around the world. 

On the other hand, particles from fossil fuel combustion and gas-to-particle conversion are generally much smaller (< 2.5-/Am diameter) and fall in the respirable size range. These particles can reach the alveolar region where gas exchange occurs. This region is not coated with a protective mucus layer, and here the clearance time for deposited particles is much greater than in the upper respiratory tract hence the potential for health effects is much greater (Phalen, 1984). 

Geothermal energy is a rapidly growing energy resource. In the year 2000, it accounted for 0.25% of the annual world-wide energy consumption. Exploitation of geothermal resources is generally far less a cause of pollution than fossil-fuel combustion. It has, however, some adverse local effects on the environment, includ-... 

Suess effects the dilution effect on 14C from inputs of fossil fuel combustion are clear after about 1850 in the early stages of the Industrial Revolution. 

The urban heat island effect has implications for chemical emissions in several ways. Elevated temperatures increase the consumption of energy for air conditioning and other cooling systems, with attendant increases in fossil fuel combustion-related contaminants (Cardelino et al., 2001 Adams, 1999). Increased ambient air temperatures also increase volatilization of POPs such as PCBs, PCNs and PBDEs from urban sources (Priemer and Diamond, 2002 Helm and Bidleman, 2003). 

Example 2 illustrates a similar cascade of effects of Nr from food production. In this case, atmospheric N2 is converted to NH3 in the Haber-Bosch process. The NH3 is primarily used to produce fertilizer. About half the Nr fertilizer applied to global agro-ecosystems is incorporated into crops harvested from fields and used for human food and livestock feed (Smil, 1999, 2001). The other half is transferred to the atmosphere as NH3, NO, N2O, or N2, lost to the aquatic ecosystems, primarily as nitrate or accumulate in the soil nitrogen pool. Once transferred downstream or downwind, the nitrogen atom becomes part of the cascade. As Figure 5 illustrates. Nr can enter the cascade at different places depending on its chemical form. An important characteristic of the cascade is that, once it starts, the source of the Nr (e.g., fossil-fuel combustion and fertilizer production) becomes irrelevant. Nr species can be rapidly intercon-verted from one Nr to another. Thus, the critical step is the. formation of Nr. 

Donora in Pennsylvania, and London. Excess mortality accompanied each of these pollution episodes and has been attributed to the smoke and sulfur dioxide generated by fossil fuel combustion. A number of recent epidemiologic, clinical, and animal studies have confirmed that both particulate matter and sulfur oxides produce adverse health effects. These adverse effects have been observed during pollution episodes in which the gas and particle concentrations do not approach the magnitude of the three incidences mentioned previously. Delineating the relative contribution of particulate matter and sulfur oxides to these adverse effects is difficult because of the chemicophysical association of sulfur oxides and particles. This section is limited to the current state of knowledge on sulfur oxides and acid aerosol-related health effects. The following section will discuss particulate matter-related effects. 

Despite the clear evidence of a subpopulation of individuals sensitive to near-ambient peak levels of sulfur dioxide, the two-decade-old NAAQS for sulfur dioxide has not been changed nor has a short-term peak standard been instituted. A considerably greater amount of attention has been placed on the contribution of airborne particulates, particularly those associated with sulfur oxides, to adverse health effects. The carbon-, mineral-, and heavy metal-based particles produced during fossil fuel combustion and smelting promote the conversion of sulfur dioxide to sulfuric acid. Recognition of sulfur dioxide-particle interactions comes as a result of findings garnered from a number of animal studies and the characterization of sulfuric acid, ammonium sulfate, and ammonium bisulfate associated with atmospheric particles. The importance of the coexistence of sulfur oxides and particulate matter is reflected in the... 

There are subtle reasons why venting carbon dioxide from trash incineration is of far less concern than the venting of the same gas from fossil fuel combustion reactions. Large portions of the carbon compounds in domestic trash are paper and food wastes. Only a few years ago the carbon contained in these plant products was part of the atmosphere. On a long-term basis, returning this carbon to the atmosphere has no effect on the overall carbon dioxide balance it simply speeds up the rate of recycle of carbon from plant material to the biosphere. 

People exposed to PAHs in conjunction with particulates from tobacco smoke, fossil-fuel combustion, coal fly ash, and asbestos fibers are at increased risk of developing toxic effects, primarily cancer. Even people not susceptible to the toxic effects of PAHs may become affected when exposure occurs in conjunction with exposure to particulates (NRC 1983). This enhanced effect results from the adsorption of PAHs onto the particulates. They are vacuolized into cells, and distributed differently in tissues depending on the size and type of particulate matter. This increased PAH uptake may result in more efficient induction of AHH activity at low PAH concentrations. This activity also increases the dose to the gastrointestinal tract as a result of mucocilliary clearance (NRC 1983). This synergistic action between PAHs and particulate matter in air pollution has been associated with the occurrence of stomach cancer in humans (Fraumeni 1975). 

In effect, the reactions in Eqns 7.3 and 7.4 bring about the reverse ofEqns 7.1 and 7.2. Another anthropogenic gas, nitric oxide (NO), scavenges ozone in a similar way (to form nitrogen dioxide, N02) and is produced by the dissociation of N20, which can be generated from fossil fuel combustion and from the decomposition... 

Weiss (1981) claimed to have detected an excess of 0.7 ppbv NzO in the northern hemisphere as opposed to the southern, but the data are marginal. More substantial is his finding of an increase of the NzO mixing ratio by about 0.2% per year during the period 1976-1980. Goldan et al (1980) deduced a rise of about 1 % yr from measurements in the upper troposphere, and Rasmussen et al. (1981) reported an annual rise of 0.4% at the South Pole. Weiss attributed the effect to the growth of fossil-fuel combustion. The true cause remains to be established, however. 

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