Atmospheric visibility effects

Airborne sulfur compounds acidification effects, 62-63,64/ atmospheric visibility effects, 63,65 human health effects, 61-62 materials degradation effects, 62 w-Alkanes, predominance of even-number compounds, 435,438,435/440 n-Alkyl monocyclic sulfides, structures,... 

Pollutant effects on the atmosphere include increased parhculate matter, which decreases visibility and inhibits incoming solar radiahon, and increased gaseous pollutant concentrations, which absorb longwave radiation and increase surface temperatures. For a detailed discussion of visibility effects, see Chapter 10. 

The greenhouse effect in Earth s atmosphere. Visible light from the sun is absorbed by the ground, which then emits infrared radiation. Carbon dioxide, water vapor, and other greenhouse gases in the atmosphere absorb and reemit heat that would otherwise be radiated from Earth into space. 

Deposition of sulfur in regions where the soils are deficient in sulfur may be considered a beneficial effect all of the other effects of sulfur air pollution are considered adverse. They include effects on human health, materials degradation, vegetation, and atmospheric visibility, and acidification of soils, watersheds and freshwaters. Limitations on the scope of this paper will greatly restrict our discussions of the details of these effects see the References 1-11 for more detailed information. 

Effects on Atmospheric Visibility. In contrast to many of the adverse effects of sulfur emissions described above, effects on... 

Aerosol Dynamics. Inclusion of a description of aerosol dynamics within air quality models is of primary importance because of the health effects associated with fine particles in the atmosphere, visibility deterioration, and the acid deposition problem. Aerosol dynamics differ markedly from gaseous pollutant dynamics in that particles come in a continuous distribution of sizes and can coagulate, evaporate, grow in size by condensation, be formed by nucleation, or be deposited by sedimentation. Furthermore, the species mass concentration alone does not fully characterize the aerosol. The particle size distribution, which changes as a function of time, and size-dependent composition determine the fate of particulate air pollutants and their... 

In the last decade or so the most (literally) spectacular observations have been of a variety of visible effects in the upper atmosphere above thunderstorms, the most colorful of which are red sprites observed in the nighttime mesosphere. Such phenomena were originally suggested by C. T. R. Wilson ca. 1925), were first observed by J. Winckler and colleagues at the University of Minnesota... 

Figure 6.12 The earth s atmosphere is transparent to visible light from the sun. This visible light strikes the earth, and part of it is changed to infrared radiation. The infrared radiation from the earth s surface is strongly absorbed by CO2, H2O, and other molecules present in smaller amounts (for example, CH4 and N2O) in the atmosphere. In effect, the atmosphere traps some of the energy, acting like the glass in a greenhouse and keeping the earth warmer than it would otherwise be.

Although ozone exists in only very small quantities in the atmosphere, it is important because less than 1 pphm (part per hundred million) can severely attack non-resistant rubbers in the strained condition. Indeed, ozone attack can be the major factor as regards lifetime when exposed to the atmosphere. The effect of ozone is to produce clearly visible and mechanically very damaging cracking of the rubber surface. It only attacks rubber in the strained condition, although with the less resistant rubbers the threshold strain for attack may be very low. Rubbers with unsaturated (C=C) bonds in the main chain have very poor ozone resistance. 

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