Polynuclear aromatic hydrocarbons coal combustion

Examples of the need for multimedia models are found in contemporary problem areas. Polynuclear aromatic hydrocarbons and metals are emitted into the atmosphere as trace impurities with the products of coal combustion. The organics have low vapor pressure and partially condense on emitted particulates in a stack plume. The particulates are transferred to the soil by dry deposition, rainout or washout. The metals manifest... 

Polynuclear aromatic hydrocarbons (PAH s) are produced in most incomplete combustion processes. Examples are internal combustion engines, effluents from coal fired electricity generating plants, tobacco smoke, and from coking operations in steel and aluminum refineries, PAH s are also present in coal tar derived and coal tar containing products such as creosote and roofing pitch. They are found in the water we drink and the air we breathe, and are a ubiquitous component of our environment. 

Polynuclear aromatic hydrocarbons (PAH) are formed by pyrosynthesis during the combustion of organic matter and have widespread occurrence in the environment. PAHs are found as trace pollutants in soil, air particulate matter, water, tobacco tar, coal tar, used engine oil, and foodstuffs such as barbequed meat. Many PAHs are carcinogenic in experimental animals (e.g., benzo(a)pyrene) and are implicated as causative agents in human cancers. Analytical techniques include HPLC and GC. Advantages of HPLC are the ability to resolve isomeric PAHs, and the selective and sensitive quantitation by UV and fluorescence detection. U.S. EPA methods for PAH are 550.1,610, and 8310. 

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]. 

CAS [a] form 50-32-8. C20H12. A polynuclear (five-ring) aromatic hydrocarbon. Found in coal tar and cigarette smoke, and in the atmosphere as a product of incomplete combustion. 

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