Tropospheric

Example of an analysis of exhaust gas by gas phase chromatography and j relative reactivity of effluents with respect to tropospheric ozone formation. I... 

Crutzen P J 1995 Overview of tropospheric chemistry developments during the past quarter century and a look ahead Faraday Disouss. 100 1-21... 

More complex ions are created lower in the atmosphere. Almost all ions below 70-80 km are cluster ions. Below this altitude range free electrons disappear and negative ions fonn. Tln-ee-body reactions become important. Even though the complexity of the ions increases, the detemiination of the final species follows a rather simple scheme. For positive ions, fomiation of H (H20) is rapid, occurring in times of the order of milliseconds or shorter in the stratosphere and troposphere. After fomiation of H (H20), the chemistry involves reaction with species that have a higher proton affinity than that of H2O. The resulting species can be... 

Viggiano A A 1993 In-situ mass spectrometry and ion chemistry in the stratosphere and troposphere Mass Spectron. Rev. 12 115-37... 

Hauck G and Arnold F 1984 Improved positive-ion composition measurements in the upper troposphere and lower stratosphere and the detection of acetone Nature 311 547-50... 

Arnold F and Henschen G 1978 First mass analysis of stratospheric negative ions Nature 257 521-2 Eisele F L 1989 Natural and anthropogenic negative ions in the troposphere J. Geophys. Res. 94 2183-96 Oka T 1997 Water on the sun—molecules everywhere Science 277 328-9... 

Apphes to particles released in the lower troposphere only the most important sink is scavenging by precipitation, so in the absence of precipitation, these particles wUl remain suspended longer. 

Tropospheric residence time only shorter lifetime appUes to urban areas where NO quickly destroys O. ... 

Mean tropospheric background for is given. Value can be much higher in polluted areas. 

In the mid-1970s, it was realized that the CFCs in widespread use because of their chemical inertness, would diffuse unaltered through the troposphere and into the mid-stratosphere where they, too, would be photolyzed by uv (<240 nm) radiation. For example, CFC-12 can photolyze ... 

T. E. Graedel, D. T. Hawkias, and L. D. CExton, Atmospheric Chemical Compounds Sources, Occurrence and Bioassay, Academic Press, New York, 1986. Atmospheric O ne 1985, World Meteorological Organization, Geneva, Switzerland (3 vols.) an excellent compendium on tropospheric and stratospheric processes. 

Although inert in the lower atmosphere (troposphere), the hilly halogenated CFCs and Halons diffuse into the upper stratosphere where they are photodissociated, ie, photolyzed, by the intense ultraviolet radiation. 

R is hydrogen, alkenyl, or alkyne. In remote tropospheric air where NO concentrations ate sometimes quite low, HO2 radicals can react with ozone (HO2 + O3 — HO + 2 O2) and result in net ozone destmction rather than formation. The ambient ozone concentration depends on cloud cover, time of day and year, and geographical location. 

Water-soluble sdanols such as (1) were found to undergo successive oxidative demethylations with tropospheric ultraviolet irradiation in the presence of suitable chromophores, such as nitrogen oxides (516). The water-soluble methylated sdicones did not promote diatom (Nap cu/apelliculosd) growth but the demethylated photo products did. The sequence of sod-induced degradation of sdicones to water-soluble species such as (1), followed by light-induced conversion to sdicate, suggests a pathway, conceptually at least, for the mineralization of sdicones. 

Air pollution (qv) problems are characteri2ed by their scale and the types of pollutants involved. Pollutants are classified as being either primary, that is emitted direcdy, or secondary, ie, formed in the atmosphere through chemical or physical processes. Examples of primary pollutants are carbon monoxide [630-08-0] (qv), CO, lead [7439-92-1] (qv), Pb, chlorofluorocarbons, and many toxic compounds. Notable secondary pollutants include o2one [10028-15-6] (qv), O, which is formed in the troposphere by reactions of nitrogen oxides (NO ) and reactive organic gases (ROG), and sulfuric and nitric acids. 

Relative changes in the components of eqn. (6) mean that PJCO2 should decrease by about a factor of three between 25 " C and 0" C. However, atmospheric concentrations of CO2 are essentially uniform, so tropospheric mixing clearly acts fast enough for this potential poleward gradient to be absent. 

On a macroscale (Fig. 2-1) as temperature varies with altitude, so does density (1). In general, the air grows progressively less dense as we move upward from the troposphere through the stratosphere and the chemo-sphere to the ionosphere. In the upper reaches of the ionosphere, the gaseous molecules are few and far between as compared with the troposphere. 

The troposphere is the region in which we live and is the primary focus of this book. 

The gaseous composition of unpolluted tropospheric air is given in Table 2-1. Unpolluted air is a concept, i.e., what the composition of the air would be if humans and their works were not on earth. We will never know the... 

What are the principal chemical reactions that take place in the chemosphere to give it its name How do they influence stratospheric and tropospheric chemical reactions ... 

Has the composition of the unpolluted air of the troposphere most probably always been the same as in Tables 2-1 and 2-2 Will Tables 2-1 and 2-2 most probably define unpolluted air in the year 2085 Discuss your answer. 

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