Climate particles

In addition to the obvious environmental effect of airborne particulate matter, there have been a number of studies which have shown that particles have direct effects on the climate. Particles can scatter and absorb solar radiation, change levels of precipitation, cause the formation of warm or cold clouds, and cause the formation of fogs or smogs. 

Clouds cover roughly two-thirds of our earth s surface and play an important role in influencing global climate by affecting the radiation budget. Cirrus clouds are one example of a cloud type whose optical properties are not accurately known. Cirrus clouds form in the upper troposphere and are composed almost exclusively of non-spherical ice crystal particles. The impact of cloud coverage on dispersion of pollution in the atmosphere is an area of great concern and intensive study. 

Dust content In hot, dry climates the opposite problem occurs. Water evaporates, and the dust and fine particles may blow away, causing pollution and a nuisance hazard. This fugitive dust is controlled by spraying the fuel pile with water containing a polymeric dust binder that physically holds the particles together. 

Climate is often viewed as the aggregate of all of the elements of weather, with quantitative definitions being purely physical. However, because of couplings of carbon dioxide and many other atmospheric species to both physical climate and to the biosphere, the stability of the climate system depends in principle on the nature of feedbacks involving the biosphere. For example, the notion that sulfate particles originating from the oxidation of dimethylsulfide emitted by marine phytoplankton can affect the albedo (reflectivity) of clouds (Charlson et ai, 1987). At this point these feedbacks are mostly unidentified, and poorly quantified. 

Aerosol spray cans were invented in 1929, and perfection of a reliable valve and development of disposable cans took place in the 1940s. Shortly thereafter, aerosol became a household word. Like many other modem conveniences, however, the aerosol spray can has drawbacks as well as advantages. Because the particles in an aerosol are extremely tiny, they are quite mobile. They last for a long time in the atmosphere and can affect the climate, as already described. They can penetrate deep into our lungs and cause adverse health effects. Thus, anthropogenic aerosols have both global and local side effects. Despite increasing scientific studies, these effects are not yet fttlly understood. 

Robbins JA (1988) A model for particle-selective transport of tracers in sediments with conveyor-belt deposit feeders. Journal of Geophysical Research 91 8542-8558 Robinson LF, Belshaw NS, Henderson GM (in press) U and Th isotopes in seawater and modem carbonates from the Bahamas. Geochim Cosmochim Acta Rosenthal Y, Boyle EA, Labeyrie L, Oppo D (1995a) Glacial enrichments of authigenic Cd and U in subantarctic sediments A climatic control on the elements oceanic budget Paleoceanography 10(3) 395-413... 

The chemistry of carbon, and radiocarbon, in the atmosphere represents one of the most important areas of environmental research today. The primary practical reason for this is the increasing attention which must be paid to the critical balance between energy and the environment, especially from the viewpoint of man s perturbations of natural processes and his need to maintain control. Probably more than other species, carbonaceous molecules play a central role in this balance. Some of the deleterious effects of carbonaceous gases and particles in the atmosphere are set down in Table 3. The potential effects of increased local or global concentrations of these species on health and climate have led to renewed interest in the carbon cycle and the "C02 Problem". It should be evident from the table, however, that carbon dioxide is not the only problem. In fact, the so-called "trace gases and particles" in the atmosphere present an important challenge to our interpretation of the climatic effects of carbon dioxide, itself [20]. 

Varves suggest themselves as another data base from which to evaluate the history of the climate. These are sequences of sediment layers deriving from fresh water streams, the summer sediment having a different particle size and color than does the spring sediment, so that the deposit for each year becomes visible... 

This is an area of strong continental climate with dry and hot summer and severe winter with strong winds that transport dust at short and long distance, for instance yellow sand phenomenon in northwest China. During air transport these soil particles absorb numerous pollutants-carcinogens, like benzo(a)pyrene and heavy metals (Ni, Cd, Co, Zn, Pb, As) both from industrial emissions into the atmosphere and waste landfill sites. 

Weatherfastness tests on coatings have shown that prolonging the dry and wet periods, i.e., extending the usual 17 minute dry cycle to a full 102 minutes and the wet period to 18 minutes, affords results which correlate much better with the Florida outdoor exposure tests. The humidity that penetrates a layer is known to interact with the various components in the coating, adversely affecting the mechanical properties of the material. The above mentioned cycle apparently corresponds much better with the climatic conditions in areas like Florida. If recirculated water is used in accelerated exposure equipment, suspended particles may adhere to the surface of the coating, producing a thin film. This obviously has a detrimental effect on the test results. 

The effects of transport on economy, people and on the environment are manifold. They include the consequences of transport accidents and fatalities, nuisance and health effects caused by steady noise exposure, air emissions and the exhaust and resuspension of particles, climate impacts by the emission of greenhouse gases, soil and water contamination, and the deterioration of natural habitats. Moreover, the financial burden of infrastructure provision and the additional travel and production costs caused by congestion should be mentioned but these items are mainly borne by transport users themselves and thus are only partly imposed on society as a whole. Not all of these effects are equally relevant for all means of transport. While accidents constitute the major problem of car travel, the railways definitely face a noise problem and air transport contributes most to the emission of climate gases. 

Schematic longitudinal profile through a semi-isolated basin located in a hot, arid climate and separated from the open sea by a narrow portal. The sill depth, although shallow, is still great enough to permit some two-way flow of surface water. The lines show inferred seawater density (g/cm ) and the arrows show current directions. The pattern of evaporite deposition is based on the relationships between brine density and precipitate composition as shown in Figure 17.1, assuming that salt particles accumulate on the seafloor through the process of pelagic sedimentation. Source-. From Scruton, P. C. (1953). American Association of Petroleum Geologists Bulletin, 37, 2498-2512.

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