Albuquerque, N.M. -- The chemical cycles in the troposphere along with pollutants of human and natural origin can alter the composition of the air and effect local, regional and global environmental quality, according to a Penn State researcher.
The troposphere -- the area of the Earth's atmosphere from the surface to ten miles above the surface where weather exists -- is also where pollution becomes a problem. In the atmosphere, a complex series of chemical reactions can alter some pollutants so that they rain out as aerosol particles or acid rain and clear the air. Other compounds remain in the air, changing, and changing again as other chemicals cause reactions.
"Pollution from megacities and biomass burning, including precursor gases to hydrogen oxides such as acetone and formaldehyde, lofted into the upper troposphere, can become the dominant hydrogen oxide source and result in efficient ozone production," says Dr. William Brune, professor of meteorology and head of Penn State's meteorology department. "These compounds can also be transported great distances before descent, possibly influencing the chemistry of remote regions."
Ozone is complicated. In the stratosphere it serves to protect life from the detrimental effects of the sun's ultraviolet radiation. At ground level, it is a pollutant implicated in respiratory problems and eye irritation. Sunlight breaks ozone apart resulting in the creation of the very reactive hydroxyl radical which begins the process that removes some pollutants from the air. However, when hydroxyl radicals break down some compounds, they produce other hydrogen oxides, which react with other pollutants and form ozone.
"The hydroxyl radical drives atmospheric oxidation by reacting with chemicals emitted from Earths surface, thus creating new chemicals that are more easily scavenged and removed by aerosols, clouds and rain," Brune told attendees today (Jan. 15) at the annual meeting of the American Meteorological Socie
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Contact: A'ndrea Elyse Messer
aem1@psu.edu
814-865-9481
Penn State
14-Jan-2001