Polycyclic aromatic hydrocarbons pahs are a large group of organic compounds with two or more fused aromatic rings. This statement was prepared to give you information about polycyclic aromatic hydrocarbons pahs and to emphasize the human health effects that may result from exposure to them. Information and translations of polycyclic hydrocarbons, aromatic in the most comprehensive dictionary definitions resource on the web. Plastic industry and petrochemical industries make use of aromatic hydrocarbons extensively.
Polycyclic aromatic hydrocarbons pahs, also polyaromatic hydrocarbons are hydrocarbonsorganic compounds containing only carbon and hydrogenthat are composed of multiple aromatic rings organic rings in which the electrons are delocalized. Heavy and constant use of fossil fuels is a predominant anthropogenic source. Naphthalene, with its two rings, is considered the simplest polycyclic aromatic hydrocarbon by us epa and cdc for policy contexts. They have a relatively low solubility in water, but are highly lipophilic. Pahs are not synthesized chemically for industrial purposes. Contamination of stormwater pond sediments by polycyclic. Polycyclic aromatic hydrocarbons pahs are a class of hazardous organic compounds consisting of three or more fused benzene rings in linear, angular, and cluster arrangements. Polycyclic aromatic hydrocarbons who guidelines for indoor. Naphthalene, anthracene, and phenanthrene are the three simplest members of this class.
And if the definition of a pah is the strict one, what is a compound that is aromatic and polycyclic, but has hetero atoms and functional groups called. Determination of parent and alkylated polycyclic aromatic. Polycyclic aromatic hydrocarbons have two or more single or fused aromatic rings with a pair of carbon atoms shared between rings in their molecules. Some nonheterocyclic polycyclic aromatic iarc publications. Polycyclic aromatic hydrocarbons national toxicology program. This document contains information for facilities which manufacture, produce, or otherwise use polycyclic aromatic compounds. Usa home product directory analyticalchromatography analytical standards additional standards chromatography environmental standards volatiles semivolatiles polycyclic aromatic hydrocarbons pahs all polycyclic aromatic hydrocarbon pah standards. A hydrocarbon a molecule made up of hydrogen and carbon containing two or more closed rings of atoms.
Polycyclic aromatic hydrocarbons pahs polycyclic aromatic hydrocarbons pahs are a class of chemicals that occur naturally in coal, crude oil, and gasoline. By definition, polycyclic aromatic hydrocarbons have multiple cycles, precluding benzene from being considered a pah. These are the hydrocarbons which comprise of aromatic rings in fused form. A few examples of aromatic hydrocarbons are provided below. Sep 26, 2019 the atsdr toxicological profile succinctly characterizes the toxicologic and adverse health effects information for the hazardous substance described here. Definition of polycyclic hydrocarbons, aromatic in the dictionary. The most common subclass of pom is the polycyclic aromatic hydrocarbons pahs.
By definition, pahs contain at least two fused rings. Polycyclic aromatic hydrocarbons pahs are formed when organic matters incompletely combust and get distributed into the air in the form of vapor or the particular phase of absorption or. Polycyclic aromatic hydrocarbons can break down by reacting with sunlight and other chemicals in the air, over a period of days to weeks. Aromatic hydrocarbons definition, examples, properties. Polycyclic aromatic hydrocarbons national pollutant inventory. The first is an alphabetical list of polycyclic aromatic hydrocarbons pahs discussed in the report and close chemical relatives, with molecular formulas and cas numbers. Some evaporate into the air when released to soil or water. Polycyclic aromatic hydrocarbons pahs are a class of chemicals that occur naturally in coal. Another way to consider pahs is molecules made by fusing two or more benzene rings.
Pahs are persistent, bioaccumulative, and toxic pbt pollutant. Other authors consider pahs to start with the tricyclic species phenanthrene and anthracene. They also are produced when coal, oil, gas, wood, garbage, and tobacco are burned. They are formed in nature and are found in many places in the environment. Another example of a potentially pahcontaining product are bathing shoes. Polycyclic aromatic hydrocarbon definition is any of a class of hydrocarbon molecules that have multiple carbon rings, and that include carcinogenic substances and environmental pollutants abbreviation pah. Not significant risk level nsrl as defined by office of. Whether in mouse pads, toys, or bathing shoes polycyclic aromatic hydrocarbons pahs are ubiquitous. Pom containing up to seven fused rings has been identified, and theoretically millions of pom compounds could be formed. Polycyclic aromatic hydrocarbons pahs consist of a variable number of fused aromatic rings. Polycyclic aromatic hydrocarbons problem chemicals. The compounds are formed by combustion of fuels, biomass and waste materials 2. Archived polycyclic aromatic hydrocarbons psl1 canada. Forest fires are the single most important natural source of pahs in canada.
Pahs containing up to six fused aromatic rings are often known as small pahs, and those. Application of the rules would lead to the conclusion that fluoranthene 8 and pyrene 4 should be antiaromatic compounds, which disagrees with their known chemical properties. Polycyclic aromatic hydrocarbons pahs see also complex hydrocarbons polycyclic aromatic hydrocarbons pahs are the largest group of carcinogenic substances we know of today. The second is a list of structural formulas ordered according to structural complexity and ratings of carcinogenic activity. The natural sources of pahs include volcanic eruptions and forest fires. Polycyclic aromatic hydrocarbons pahs are emitted into the canadian environment from both natural and anthropogenic sources. Exposure to polycyclic aromatic hydrocarbons usually occurs by breathing air contaminated by wild fires or coal tar, or by eating foods that have been grilled. Additional guidance on who must report, reportable quantities, and how to estimate annual releases can be found in the following sections. Polycyclic aromatic hydrocarbon definition of polycyclic. Aromatic hydrocarbons are circularly structured organic compounds that contain sigma bonds along with delocalized pi electrons. Polycyclic aromatic hydrocarbons pahs include a heterogeneous group of organic contaminants, resulting due to the incomplete combustion of organic material. Polycyclic aromatic hydrocarbons pahs fact sheet epa.
They are also referred to as arenes or aryl hydrocarbons. Polycyclic aromatic hydrocarbons pahs polycyclic aromatic hydrocarbons pahs are a group of more than 100 chemicals that are also called polynuclear aromatic hydrocarbons. Examination of the sources of polycyclic aromatic hydrocarbon pah in urban background soil. These are found in coal, tar, oil and some of the cooked foods such as smoked fish, burnt toast, etc. Rather than industrial sources, the major source of pahs is the incomplete combustion of organic material such as coal, oil and. Pahs generated from these sources can bind to or form small particles in the air. These rings share one or more sides and contain delocalized electrons. Polycyclic aromatic hydrocarbons pahs are a large group of organic compounds.
Structural formulas of selected polycyclic aromatic hydrocarbons pahs. Introduction 5 extrapolation of the huckel theory to polycyclic aromatic hydrocarbons is more difficult. Pahs predominantly form dna adducts by binding to c8 of guanine 36. Polycyclic aromatic hydrocarbons usually enter the air when released to the environment. Polycyclic aromatic hydrocarbons have a looser definition allowing hetero atoms. Pahs are released from burning coal, oil, gasoline, trash, tobacco, and wood. Pahs have been found in at least 600 of the 1,430 national priorities list sites identified by the environmental protection agency epa. Definition page for polynuclear aromatic hydrocarbons. Contamination of environment with polycyclic aromatic. Spitzer is particularly adept at observing this family of molecules, which are useful indicators of organic chemistry and the possibilities for life throughout the universe. Also known as pahs or polynuclear aromatic hydrocarbons.
Most of the pahs with low vapour pressure in the air are adsorbed on particles. However, since releases from that source are generally widely separated in time and space across the country, they do not result in continuous. Polycyclic aromatic hydrocarbons members of a class of arenes called polycyclic aromatic hydrocarbons possess substantial resonance energies because each is a collection of benzene rings fused together. Polycyclic aromatic hydrocarbons pahs are a group of more than 100 different chemical compounds. Hightemperature cooking, such as grilling, will form pahs in meat and other foods.
Polycyclic aromatic hydrocarbons what are polycyclic aromatic hydrocarbons. Polycyclic aromatic hydrocarbons pahs are a class of chemicals that occur naturally in coal, crude oil, and gasoline. Polycyclic aromatic hydrocarbons definition of polycyclic. May 31, 2017 polycyclic aromatic hydrocarbons pahs are a group of more than 100 chemicals that are also called polynuclear aromatic hydrocarbons. Polycyclic aromatic hydrocarbons pahs factsheet national. Lists of polycyclic aromatic hydrocarbons polycyclic. It can be observed that all these compounds contain a benzene ring. Polycyclic aromatic hydrocarbons pahs are very widespread environmental. Nistspecialpublication922 polycyclicaromatichydrocarbon structureindex lanec. Polynuclear aromatic hydrocarbon molecules contain only carbon and hydrogen atoms. Hightemperature cooking will form pahs in meat and in other. The environmental protection agency epa has identified 1,408 hazardous waste sites as the most serious in the nation. The polycyclic aromatic hydrocarbons benzoapyrene, benzobfluoranthene, benzojfluoranthene, benzokfluoranthene, and indeno1,2,3cdpyrene are considered to be entering the environment in a quantity or concentration or under conditions that may constitute a danger to human life or health.
Most frequently, nonbranded products at affordable prices get negative attention in this respect, but products from renowned companies may contain pahs as well. The concentrations of the 16 priority pollutant pahs ranged from. The role of coal tarbased sealcoat products as a source of pahs. Polycyclic aromatic hydrocarbons, dust, sewagesludge 1. Polycyclic aromatic hydrocarbons pahs how people are. Jrcirmm catalogue pdf format or jrcirmm catalogue search engine. Based on feedback from you, our users, weve made some improvements that make it easier than ever to read thousands of publications on our website. The term pah refers to compounds consisting of only carbon and hydrogen atoms. Pdf polycyclic aromatic hydrocarbons pahs are a class of hazardous organic. Jun 27, 2005 many spitzer space telescope results involve the detection or study of polycyclic aromatic hydrocarbons, or pahs for short. Introduction polycyclic aromatic hydrocarbons pahs are a large group of chemical compounds, i, with a similar structure comprising two or more joined aromatic carbon rings 1.
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