Polycyclic aromatic hydrocarbons PAHs emission

Mastral AM, Callen MS. A review on polycyclic aromatic hydrocarbon (PAH) emissions from energy generation. Environ Sci Technol 2000 34 3051-7. 

Xiaofang, Y. (2008). Polycyclic aromatic hydrocarbon (PAH) emission from co-firing municipal solid waste (MSW) and coal in a fluidized bed incinerator, Waste Manage., 28, pp. 1543-1551. 

Unbumed Hydrocarbons Various unburned hydrocarbon species may be emitted from hydrocarbon flames. In general, there are two classes of unburned hydrocarbons (1) small molecules that are the intermediate products of combustion (for example, formaldehyde) and (2) larger molecules that are formed by pyro-synthesis in hot, fuel-rich zones within flames, e.g., benzene, toluene, xylene, and various polycyclic aromatic hydrocarbons (PAHs). Many of these species are listed as Hazardous Air Pollutants (HAPs) in Title III of the Clean Air Act Amendment of 1990 and are therefore of particular concern. In a well-adjusted combustion system, emission or HAPs is extremely low (typically, parts per trillion to parts per billion). However, emission of certain HAPs may be of concern in poorly designed or maladjusted systems. 

Acridine is a three-ring nitrogen heterocycle, classified as polycyclic aromatic hydrocarbons (PAHs), some of which are proposed to be human carcinogens based on the evidence of carcinogenicity in experimental animals. Acridine is present in crude oil and tar pitch, as well as in emissions resulting from their combustion. 

Human exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAH) occurs through inhalation of tobacco smoke and polluted indoor or outdoor air, through ingestion of certain foods and polluted water, and by dermal contact with soots, tars, and oils CO. Methylated PAH are always components of these mixtures and in some cases, as in tobacco smoke and in emissions from certain fuel processes, their concentrations can be in the same range as some unsubstituted PAH. The estimated emission of methylated PAH from mobile sources in the U.S. in 1979 was approximately 1700 metric tons (2). The occurrence of methylated and unsubstituted PAH has been recently reviewed (1, 2). In addition to their environmental occurrence, methylated PAH are among the most important model compounds in experimental carcinogenesis. 7,12-Dimethylbenz[a]anthracene, one of... 

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]. 

Kohler, M., Kunniger, T., Schmid, P., Gujer, E., Crockett, R., and Wolfensberger, M. Inventory and emission factors of creosote, polycyclic aromatic hydrocarbons (PAH), and phenols from railroad ties treated with creosote. Environ. Sci. Technol, 34(22) 4766-4772, 2000. 

In 1978, the emission of benzo(a)pyrene (BaP) from an aluminum plant In the vicinity of Sundsvall, Sweden, was estimated to be about four times the total amount emitted from all the motor vehicles In that country. As might be expected, the result of this estimate caused considerable concern, and a survey of the air quality In the Sundsvall area was made In 1980-81. The program monitored concentrations of polycyclic aromatic hydrocarbons (PAH) and fluoride In ambient air, with samples being collected once each week. Concentrations of fluoride and meteorological data were measured by the aluminum company laboratory, while PAH concentrations were determined by the Norwegian Institute for Air Research (NILU). 

Fromme, H., Oddoy, A., Piloty, M., Krause, M. and Lahrz, T. (1998a) Polycyclic aromatic hydrocarbons (PAH) and diesel engine emission (elemental carbon) inside car and a subway train. The Science of the Total Environment, 217,165-73. 

Often, many simultaneously occurring pollutants or contaminants determine an environmental problem. In industry, agriculture, and households, products are often mixtures of many compounds. The process of production and consumption is accompanied by emissions and consequently by contamination. One example is the use of toxaphene in the past, a very complex mixture of polychlorinated camphenes, as a pesticide. Technical toxaphene consists of more than 175 individual compounds. A second example is industrial and domestic emissions resulting from the combustion of fossil fuels. The emissions contain both a mixture of gases (SO2, NOx, CO2, etc.) and airborne particulate matter which itself contains a broad range of heavy metals and also polycyclic aromatic hydrocarbons (PAH). 

Nitro-polycyclic aromatic hydrocarbons, referred to as nitro-aromatic compounds hereafter, constitute one of the most troubling classes of environmental pollutants. They are derivatives of polycyclic aromatic hydrocarbons (PAHs) that contain two or more fused aromatic rings made of carbon and hydrogen atoms and at least one nitro group (Fig. 10.1). Concern about these compounds arises partly from their ubiquity nitro-aromatic compounds are released to the environment directly from a variety of incomplete combustion processes [1] and are also formed in situ by atmospheric reactions of PAHs [2]. Nitro-aromatic compounds have been found in grilled food in diesel, gasoline, and wood-smoke emissions and are commonly found in atmospheric particulate matter, natural waters, and sediment [3-8],... 

In this chapter, the different steps in the assessment of mixture exposure are discussed. The chapter starts from emission scenarios and subsequently discusses transformation processes taking place in the environment and their effects on mixture composition. Next, bioavailability is discussed, and exposure scenarios for both humans and biota in the environment are described. These descriptions also consider methods to assess exposure to mixtures. Most data available on mixture exposure are restricted to North America and Europe, but we recognize that there are emerging problems in other regions of the world. We restrict our discussion to man-made chemicals and those natural chemicals subject to regulation (metals, polycyclic aromatic hydrocarbons (PAHs)), because these represent the most well-studied group and the current priorities for risk assessment. 

Very small grains and macromolecules are known to be present in the surface layers of some disks as well as in the ISM. They are usually revealed by emission features due to polycyclic aromatic hydrocarbons (PAHs, see also Chapter 6). These particles, with frameworks of six to several thousand carbon atoms, are so small that they can be excited by single ultraviolet photons. Subsequently, they will non-thermally re-radiate the energy in discrete, but broad, bands stretching across the mid-infrared wavelength region. They are found in protoplanetary disks when the ultraviolet radiation field is sufficiently high (Habart et al. 2004), but... 

Combustion processes of fossil fuels are currently the main source of energy generation. It is well known that, in these processes, pollutants -such as SO2, NOx and CO2 and CO-are emitted to the atmosphere. Organic emissions, whose harmful nature has become the cause of growing concern, are another important source of pollution released in these processes. In fact. Polycyclic Aromatic Hydrocarbons (PAH) have been widely studied and their carcinogenic and mutagenic potential has been a matter of considerable concern [1,2]. These emissions can be minimized by combustion optimization but not completely... 

The polycyclic aromatic hydrocarbons (PAHs) have been inferred to exist in the interstellar dust by the correlation of their general infrared spectral characteristics with observed celestial infrared emission bands [13-15]. 

ABSTRACT The size distribution of polycyclic aromatic hydrocarbons (PAHs) on different particle size fractions in the fly ash emissions from biomass combustion have been measured by gas chromatography (GC) and mass spectrometer (MS). 

See also Charcoal Coke Oven Emissions Polycyclic Aromatic Hydrocarbons (PAHs). 

Pyrene is used in biochemical research. Polycyclic aromatic hydrocarbons (PAHs) occur naturally in coal tar, fossil fuel combustion, forest fires, and open flame grilled meats. PAHs are found in cigarette smoke and in diesel emissions, when asphalt surfacing and tar roofing, and also in aluminum and coke plants. Pyrene was used in the 1930s as an insecticide. 

Once processed into products such as motor gasoline and fuel oil, most of the petroleum is burned in engines or boilers to provide energy for transportation, space heating, or electricity. In these combustion processes, the petroleum fuel is oxidized. Because of incomplete oxidation, small amounts of hydrocarbon emissions result. These emissions often contain much larger percentages of combustion by-products such as polycyclic aromatic hydrocarbons (PAHs) than the initial petroleum products. Incomplete combustion and heat also alter the composition of crank case oils and lubricants. 

Scientific research confirms that biofuel has a less harmful effect on human health than petroleum fuel. Biofuel emissions have decreased levels of polycyclic aromatic hydrocarbons (PAHs) and nitrited PAH compounds (nPAH), which have been identified as cancer causing compounds. Test results indicate that PAH compounds were reduced by 50-85%. Targeted nPAH compounds were reduced by 90%. Biofuel is nontoxic and biodegradable. In addition, the flash point (the lowest temperature at which it can form an ignitable mix with air) is 300° F, well above petroleum fuel s flashpoint of 125°F. 

Garrigues P, Ewald M. 1987. High resolution emission spectroscopy (Shpol skii effect) A new analytical technique for the analysis of polycyclic aromatic hydrocarbons (PAH) in environmental samples. Chemosphere 16 485-494. 

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