Fossil fuels: burning 1448 generally

Chromium has now also become a common contaminant of the human environment. Possible sources of chromium exposure to the general public are emissions and waste dumps from the industry, causing local air and water pollution. Emissions from fossil-fuel burning also contribute to the atmospheric load. The presence of chromium in phosphates and in municipal sewage sludge used as fertilizers may be another important source of Cr in soil, in water and in some foods. 

Polycyclic aromatic hydrocarbons (PAHs, sometimes also called polynuclear aromatics, PNA) are a hazardous class of widespread pollutants. The parent structures of the common PAHs are shown in Fig. 4 and the alkylated homologs are generally minor in combustion emissions. PAHs are produced by all natural combustion processes (e.g., wild fires) and from anthropogenic activity such as fossil fuels combustion, biomass burning, chemical manufacturing, petroleum refining, metallurgical processes, coal utilization, tar production, etc. [6,9,15,18, 20,24,131-139]. 

Burning oil, like burning any fossil fuel, releases extra carbon dioxide and other pollutants into the atmosphere. Oil is generally cleaner than coal, but the DOE states that many current environmental laws are aimed at reducing the amount of pollution created by burning oil. Scientists are learning how to remove pollutants from oil before it is burned so that it produces fewer emissions. 

We wish to alert the reader that in the analyses presented above, the results were essentially independent of the type of fuel used. From an efficiency point of view, this may be true, but from a sustainability point of view, it is not. In general, gas is a much cleaner burning fuel than coal and requires less pre- and posttreatment. Even though the standard power generation plants can be made more efficient using thermodynamic analysis (lost work, availability, or exergy analysis), we note that power generation based on fossil fuels is not sustainable since the combustion of these fuels leads to increased... 

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