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Encyclopedia > Peroxyacyl nitrates
peroxyacetyl nitrate, the most common PAN
peroxyacetyl nitrate, the most common PAN

Peroxyacyl nitrates, or PANs, are powerful respiratory and eye irritants present in photochemical smog. They are formed from a peroxyacid radical and nitrogen dioxide, for example peroxyacetyl nitrate, CH3COOONO2. Photochemical smog is the term to represent a multitude of chemical agents which are considered to be detrimental to the environment and health. ... In chemistry, radicals (often refered to as free radicals) are atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... The chemical compound nitrogen dioxide (NO2) is a red or orange/brown gas with a characteristic sharp, biting odor. ...

PANs are both toxic and irritating, as they disolve more readily in water than ozone. At concentrations of only a few parts per billion they cause eye irritation. At higher concentrations they cause extensive damage to vegetation. Both PANs and their chlorinated derivates are said to be mutagenic, as they can be a factor causing skin cancer. Ozone (O3) is an allotrope of oxygen, the molecule consisting of three oxygen atoms instead of the more stable diatomic O2. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... In biology, a mutagen (Latin, literally origin of change) is an agent that changes the genetic information (usually DNA) of an organism and thus increases the number of mutations above the natural background level. ... In medicine (dermatology), there are several different types of cancer referred to under the general label of skin cancer. ...

PANs are secondary pollutants, which means they are not directly emitted as exhaust from power plants or internal combustion engines, but they are formed from other pollutants by chemical reactions in the atmosphere. Free radical reactions catalyzed by ultraviolet light from the sun oxidize unburned hydrocarbons to aldehydes, carboxylic acids, and finally peroxyacids, which combine with nitrogen dioxide to form peroxyacyl nitrates. A fossil fuel power plant (FFPP) (also known as steam electric power plant in the US, thermal power plant in Asia, or power station in the UK) is an energy conversion center designed on a large scale for continuous operation. ... An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. ... In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... An aldehyde is either a functional group consisting of a terminal carbonyl group, or a compound containing a terminal carbonyl group. ... In chemistry, carboxylic acids (also called alkanoic acids) are organic acids characterized by the presence of a carboxyl group. ... The chemical compound nitrogen dioxide (NO2) is a red or orange/brown gas with a characteristic sharp, biting odor. ...

Since they dissociate quite slowly in the athmosphere into radicals and NO2, PANs are able to transport these unstable compounds far away from the urban and industrial origin. This is important for tropospheric ozone production as PANs transport NOx to regions where it can more effficiently produce ozone. Radical is derived from the Latin word radix, which means root. In various fields of endeavor, it can mean: Sciences in chemistry, either an atom or molecule with at least one unpaired electron, or a group of atoms, charged or uncharged, that act as a single entity in reaction. ... Ozone (O3) in the troposphere, is a pollutant, a constituent of smog. ... NOx is a generic term for the various nitrogen oxides produced during combustion. ...

  Results from FactBites:
JAIC 1993, Volume 32, Number 1, Article 6 (pp. 59 to 79) (916 words)
PAN is the first and most abundant member of a family of compounds, the peroxyacyl nitrates (RC(O)OONO2, R = alkyl group), which were not known to chemists until they were identified in urban smog in the early 1960s (Stephens 1969).
PAN and other peroxyacyl nitrates are mutagens, eye irritants, and phytotoxins (Peak and Belser 1969; Taylor 1969; Stephens 1969; Temple and Taylor 1983; Shepson et al.
Peroxyacyl nitrate has been identified in urban air since the mid-1960s (Stephens 1969); its concentrations may reach 30–50 ppb during smog episodes (Stephens 1969; Grosjean 1984; Williams and Grosjean 1990).
  More results at FactBites »



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