Wind erosion

Particulate emissions are controHed mainly through venting, baghouses and water scmbbers. Atmospheric zinc loss is estimated at 100 g/1 or zinc mines, mostly from handling dry ore and concentrate and wind erosion of tailing pHes. Sulfur dioxide emissions have been reduced by installing double absorption acid plants and improved containment of dilute gases. 

Lagoons are, in effect, inexpensive reac tors. They are shallow basins either cut below grade or formed by dikes built above grade or a combination of a cut and dike. The bottom must be lined with an impermeable barrier and the sides protected from wind erosion. These systems are best used where large areas of inexpensive land are available. 

Wind erosion of contaminated soils —Vehicle travel over contaminated roadways... 

Air is made up of a mixture of different gases and material from natural processes such as wind erosion, evaporation from the sea, earthquakes, and from human activity in the form of combustion products from processes and vehicles. 

Studies of atmospheric particles show that their distribution is often birno-dal i.e., the particles are made up of rwo separate fractions, one with fine and one with coarse particles (Fig. 9.1). The coarse particles, from about 2.5 pm upward, are made up of natural dust from the effect of wind, erosion, plants, volcanoes, etc. The finer fraction is made up of particles smaller than 2.5 pm and consists primarily of particles from human activity, combustion, traffic, and processes. 

A type of wind erosion analysis that has been extensively studied is the effect of water drop erosion on rapidly moving missile parts. 

Wind erosion has removed the TCDD from the point of application. 

Fugitive dusts are caused by wind erosion on waste sites, by vehicular traffic, and by excavation of waste during remedial action. The most commonly used control methods include the following ... 

Figure 26.34 can be used to find the soil loss ratio due to the slope of the site as used in the Universal Soil Loss Equation. Loss from wind erosion can be determined by the following equation ... 

The semi-arid areas receiving somewhat higher rainfall are covered by a steppe-like fairly continuous vegetative cover of Xerophilous shrubs and grasses. In the Central Asian Plains, east of the Caspian Sea, wind erosion and transport are the dominant features. Sand dunes dominate the landscape for hundreds of kilometers. 

Trace elements can be transported out of arid soils through plant biomass removal and erosion/leaching. Plant biomass removal is through production of food, feedstuff, and fiber plants. Wind erosion is a serious loss of surface soils and trace element outputs from arid and semi-arid soils as discussed in the first chapter. 

The vast area of Arid and Semi-Arid ecosystems of Central and East Asia is subject to wind erosion. The major natural sources of dust emission are Gobi desert (Xinjiang... 

Photochemical transformation of benzole (e)pyrene (BeP), a polycyclic aromatic hydrocarbon, adsorbed on silica gel and alumina surfaces, is reported by Fioressi and Arce (2005). This study was designed to define the atmospheric degradation of the PAH adsorbed on particulates that originated from wind erosion of the land surface. It can be assumed that similar behavior occurs at the land surface-atmosphere interface. 

Significant dispersion of hexachlorobutadiene has been confirmed by the detection of hexachlorobutadiene at areas which are far removed from release sources (Class and Ballschmiter 1987). A high partition coefficient (log Ko=) value of 3.67 (Montgomery and Welkom 1990) for hexachlorobutadiene indicates that adsorption to soils with high organic carbon content can occur. Wind erosion of contaminated surface soils can then lead to airborne hexachlorobutadiene-containing particulate matter. Levels of hexachlorobutadiene have been detected in fly ash from the incineration of hexachlorobutadiene-containing hazardous waste (Junk... 

Figure 2 shows results at the ground site for a one-week period in June, when crops (corn and soybeans) were short enough to allow the generation of soil aerosols through cultivation and wind erosion. Figure 3 shows results from the tower sampler for a two-week period in July when crops were mature. Cultivation should have been absent, and wind erosion very limited, during this period. 

Figure A and 5 show results for a period during and after harvest, in October and November, 1978. Generation of soil aerosol by tilling was observed, and wind erosion was possible, during this period because of the removal of the crop cover from the soil surface. Figure A shows results of three weeks of sample collection from the ground site, and Figure 5 shows results from four weeks of sampling on the tower.

Figures 4 and 5 show results of sampling over about one month in the fall mid-October to mid-November 1978. This period included harvest activities as well as post-harvest plowing and other tilling operations. These activities were visually observed to mobilize a considerable amount of soil material. This is reflected in the increased concentrations over those of July (Table II). Moreover, mean concentrations during the fall period approached, and in one case exceeded, those of June, when tilling and wind erosion were also active.

Poor maintenance of topsoil is also a major concern. Synthetic fertilizers have no organic bulk and do not provide a food source for soil microorganisms and earthworms. Over time, a soil treated with only these fertilizers loses biological activity, which diminishes the soil s fertility. Soils void of organic bulk become chalky and susceptible to wind erosion. Chalky soils lose their capacity to hold water, which means that more applied fertilizer is leached away. Ever-increasing amounts of fertilizer are thus needed. 

Fig. 5. Example of a stratigraphic trap. This unconformity represents the condition where upward movement of oil has been halted by the impermeable cap rock laid clown across tine cutoff (possibly by water or wind erosion) surfaces of the lower beds. This type of reservoir is found in the great East Texas field...

Etyemezian V, Nikolich G, Ahonen S, Pitchford M, Sweeney M, Purcell R, Gillies J, Kuhns H (2007) The Portable In Situ Wind Erosion Laboratory (PI-SWERL) a new method to measure PM10 windblown dust properties and potential for emissions. Atmos Environ 41 (18) 3789-3796... 

Mineral dust (MD) is a ubiquitous PM component generated by multiple sources including natural wind erosion, agriculture and other anthropogenic activities (e.g. construction works, re-suspension by traffic). Its natural elemental composition consists of Si, Al, Ca, K, Ti, Fe, Na (non-sea-salt) and oxygen, as most of the compounds are found in form of their oxidic minerals. 

Globally, volcanoes release about 17 150 metric tons (t) of arsenic per year into the atmosphere (It equals 1000 kg (Matschullat, 2000), 300). Other significant natural sources of gaseous arsenic emissions include geothermal vents, wind erosion of soils and sediments, forest and coal seam fires, and sea spray ((Cullen and Reimer, 1989), 740 (Nriagu, 1989) Chapter 3). Under reducing conditions in soils, fungi and... 

Loess is especially common in parts of China and US Midwestern states. Chinese loess primarily forms from the wind erosion of the uplifting Himalaya Mountains under arid and semiarid conditions. In the US Midwest, loess accumulated as winds scoured deposits left by retreating glaciers about 10000 years ago (Press and Siever, 2001), 318-319. 

The aim of this work is to estimate more accurately fugitive dust emissions due to wind erosion of exposed aggregate storage piles. The model constructed allows to quantify the temporal evolution in the mass flux when a bed of materials is exposed to a turbulent flow. It is based on the interaction between particles take-off and wall turbulence. The model allows as well to take into account materials having a wide size distribution, which is typical of materials such as coal or ore. Some experimental studies have shown a temporal decrease in the mass flux as the bed contains a wide range of particle sizes. This decrease, due to large particles, is predicted by the model. The rate depends on the flow velocity and the characteristics of the particles. 

Keywords Fugitive dust emissions Wind erosion Particle take-off Mass flux... 

Atmospheric diffuse dust emissions constitute a pollution source, which is difficult to be quantified. In fact, a diffuse emission is defined as a polluting atmospheric flux which is spread out over a large area or which is not concentrated [1]. In the case of steelwork sites, diffuse dust emissions can represent many as 20% of airborne particle pollution, they result from conveyances and handling of materials and from wind erosion of exposed aggregate storage piles. This latter category of emission source is widely predominant. 

The aims of the investigations presented in this paper are to estimate accurately fugitive dust emissions resulting from wind erosion. Thus, a model which allows to quantify emissions resulting from an exposed particle bed to a turbulent flow has been developed. Its originality is to take into account the wide particle size distribution of materials used, as example, at steelwork sites. Typically, the finer particles can have a size of about 10 xm and the larger running to centimetres. This characteristic is very important. In fact, Meunier [2] observed for various experimental tests carried... 

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