upload
Sam Houston State University (SHSU)
Industrie: Education
Number of terms: 13052
Number of blossaries: 0
Company Profile:
Founded in 1879 and named after Texas' greatest hero General Sam Houston, Sam Houston State University is public shcool within the Texas state university system and located in Huntsville, Texas. It's a multicultural institution that offers 79 bachelorette degree programs, 54 masters and five ...
Chemical formula CBrClF<sub>2</sub> Synonyms: Halon 1211, Freon 12B1, chlorodifluorobromomethane. This chemical belongs to the freon family. Halon 1211 was introduced in the 1960s as an effective gaseous fire suppression agent for application in the protection of computer control rooms, museums, telecommunication switches and other areas containing highly valuable materials. Results of studies done in the late 1980s indicated that the agent was an ozone depleting chemical. This chemical is stable in the troposphere but photodissociates to yield halogen radicals in the upper atmosphere, which can catalytically destroy stratospheric ozone.
Industry:Chemistry;Weather
Consist of emissions from on-road and off-road sources. Cars, light, medium and heavy-duty trucks are considered on-road mobile sources, off-road mobile sources; are tractors, lawn mowers, boats, and airplanes. Although the off road sources usually put out more pollution per hour of work than the on-road, the great number of on-road source put out a larger overall volume into the atmosphere.
Industry:Chemistry;Weather
These are particles that are formed in the atmosphere due to both the chemical and physical processes that take place with the interactions of primary gaseous emissions. The primary gaseous emissions are injected into the atmosphere by combustion processes such as from a car or from a coal burning plant.
Industry:Chemistry; Weather
These are particles that are formed in the atmosphere due to both the chemical and physical processes that take place with the interactions of primary gaseous emissions. The primary gaseous emissions are injected into the atmosphere by combustion processes such as from a car or from a coal burning plant.
Industry:Chemistry; Weather
(C<sub>2</sub>H<sub>4</sub>O<sub>2</sub>), also called hydroxyacetaldehyde, is formed during the oxidation of ethane and isoprene, and also by the emission of biomass fires. It is the simplest form of sugar. Glycol aldehydes have also been found in trace amounts in dust clouds near the Milky Way of outer space.
Industry:Chemistry; Weather
(C<sub>6</sub>H<sub>5</sub>CH<sub>3</sub>) A highly volatile and water-soluble benzene derivative that is highly toxic to most forms of life. Its estimated lifespan in the atmosphere--with respect to a photochemical reaction with hydroxyl radical---is 60 hours and this hydrocarbon is eventually oxidized to carbon dioxide. Toluene is used in a variety of industries including the manufacture of TNT, pharmaceuticals, rubbers, and other benzene derivatives, and is also a fuel additive and a paint solvent. Toluene also reaches the atmosphere from natural sources such as coal tar, mineral oils, and forest fires.
Industry:Chemistry; Weather
(CF<sub>3</sub>CF<sub>2</sub>CF<sub>2</sub>CF<sub>2</sub>CF<sub>2</sub>CF<sub>2</sub>CF<sub>2</sub>CF<sub>2</sub>SO<sub>3</sub><sup>-</sup>) An intermediate in the production of fabric protectors that repelled water and oil, among other uses. PFOS is toxic to mammals. In 2005, Dupont decided to phase-out an analogue to this compound, perfluorooctanoic acid, by 2015 because of its widespread detection in blood of marine and Arctic animals. The 3M company is phasing-out perfluorooctane sulfonate for similar reasons. Recent data have shown that blood donors in Minneapolis-St. Paul, Minnesota have a lower blood concentration of members of this family after a 2000-2002 phase-out of perfluorooctanesulfonyl-fluoride.
Industry:Chemistry; Weather
(CH<sub>2</sub>CHCHO) The simplest double-bonded aldehyde, produced in urban smog, contributing greatly to eye and lung irritation. It is a constituent of internal combustion engine exhaust, cigarette smoke, and biomass burning, and from the incomplete combustion of plastics and fuels.
Industry:Chemistry; Weather
(Freon<sup>®</sup>-11, CFC-12) One of the principal greenhouse gases, a gas with absorption bands in the infrared portion of the spectrum. There is extensive evidence showing that a class of synthetic compounds, the chlorofluorocarbons (CFCs), are responsible for the destruction of the ozone layer. CFCs are molecules that contain one or more atoms of both chlorine and fluorine. In September of 2004, the ozone hole over Antarctica was the largest area ever recorded and was almost THREE times larger than the area of the U. S. Because CFCs are so unreactive, they do not break down when released into the air in the troposphere where they are spilled. In time, air currents and diffusion carry them into the stratosphere, where, under the influence of UV radiation, they release chlorine radicals that initiate the destruction of ozone. Data collected by NASA have shown conclusively, that there is an inverse relationship between ozone concentration and the chlorine monoxide radical in the stratosphere; ClO is formed by chlorine atom attack on O<sub>3</sub>. CFCs are very useful inert, nontoxic, nonflammable compounds that had been used for years as coolants and as spray can propellants for aerosol forms of hair sprays and deodorants. They had been unsurpassed as solvents for cleaning electronic microcircuits. Commercially, the most important CFCs are the halogenated methanes, Freon-11 (trichlorofluoromethane) and Freon-12 (dichlorodifluoromethane). Over 50% of asthma inhalers contain chlorofluorocarbons as the solvent and gaseous propellent. These CFCs have relatively recently been prohibited in all products except in those medicinal inhaler dispensers for asthmatics and a few other limited exceptions. In Finland alone there are over a million medicinal dispensers that disperse freons into the atmosphere. This is equal to the freon concentration of the cooling devices in approximately l00,000 refrigerators.
Industry:Chemistry; Weather
(HCFC-22) CHClF<sub>2</sub>, this chemical is an intermediate replacement for the old CFCs because it contains a hydrogen atom, making a molecule that is easily attacked by hydroxyl radical in the atmosphere, therefore causing it to have a shorter atmospheric lifetime compared to the CFCs it replaces. In the U. S. HCFC-22's use is already being phased out but the phase out in developing countries like India is stumbling and this may lead to a slower healing of the stratospheric ozone layer's ozone.
Industry:Chemistry; Weather