Dust, wind-blown

The primary constituents to be measured are the pH of precipitation, sulfates, nitrates, ammonia, chloride ions, metal ions, phosphates, and specific conductivity. The pH measurements help to establish reliable longterm trends in patterns of acidic precipitation. The sulfate and nitrate information is related to anthropogenic sources where possible. The measurements of chloride ions, metal ions, and phosphates are related to sea spray and wind-blown dust sources. Specific conductivity is related to the level of dissolved salts in precipitation. 

Wind-blown dust 1 missions Sea spray Volcanoes Plant particles... 

Additional sources of U to the oceans are dissolution of wind-blown dust and groundwater discharge. The former is unlikely to be significant and a 10% release of U from dust would amount to only about 3% of the riverine U flux. Groundwater may introduce a more significant flux of U but this is extremely difficult to estimate as both the total flux of groundwater to the ocean and the average U concentration of such waters are poorly known (Dunk et al. 2002). 

Some identified modes are evaporation through a stack emission through a vent (a vent is not designed to elevate the emitted material—a stack is) leaks in plumbing or storage containers and wind-blown dust. 

Particles from natural sources (such as wind blown dusts from deserts, sea spray, volcanos and vegetation) and man-made from mechanical processes. 1.6-11.5 2.9 2.33... 

It is seen that the distribution is bimodal, with the coarse mode dominating the aerosol volume concentrations. The 1979 average volume concentration of aerosol less than 10 ym diameter was 32.4 ymVcm. From its large standard deviation, it is clear that the coarse particle mode exhibited considerable variation throughout the year. Records show that high coarse mode volume concentrations accompanied moderate-to-high wind speeds. The coarse material was very likely wind-blown dust of crustal composition. 

To estimate the contribution of wind-blown dust of crustal origin to the fine aerosol concentration, elemental enrichment factors were calculated using the method of Macias et al. (20). The enrichment factor, EF., for an element i was calculated as follows ... 

Iron was chosen as the reference element because its major source is likely to be soil and it is measured with good accuracy and precision by FIXE. Crustal abundances were taken from Mason (21). Enrichment factors greater than 1 indicate an enrichment of that element relative to crustal abundances values less than 1 indicate a depletion. The results of this calculation are shown in Table 4. For this calculation it was assumed that ammonium and nitrate accounted for all aerosol nitrogen. It is seen that Si and Ca are near their crustal abundance, indicating a probable soil dust source. The low EF for Al is probably due to a systematic error in the Al measurement rather than a true depletion. Potassium, although present in small concentrations, is slightly enriched relative to crust. The other fine aerosol species, C, N, S, and Pb are enriched by factors of thousands over their natural crustal abundance, indicating that they are not due to wind-blown dust. 

The median value will be somewhat less that this, since i number of wind-blown dust episodes contributed the most to the average coarse particle contribution. 

The symposium was divided into four subject areas, and this volume follows that general format. The first group of chapters reviews and describes many of the recent modeling efforts. The next section is devoted to source characterization studies, while the third group includes chapters concerned with carbonaceous aerosols—both source apportionment and measurement techniques. The final section describes the results of several field studies in areas of the United States and China where wind-blown dust is a serious problem. 

Land releases of radium are related to atmospheric fallout of coal fly ash (see Section 5.2.1). For example, elevated radium-226 concentrations in snow have been detected near a coal-fired power plant in Poland (Jaworowski et al. 1971). Other land releases may include the disposal of coal fly ash, lime slurry derived from water softening processes, and uranium mine tailings and associated wind-blown dusts. However, no information was located on the total amount of land-released radium... 

There have been many attempts to reduce the migration of toxic metals from soils, and at the same time improve the appearance of derelict sites by the introduction of metal-tolerant ecotypes (Bradshaw et al., 1965 Gemmel, 1977 Bradshaw and Chadwick, 1980). Many such sites are poor in micronutrients and must first be treated with soil amendments such as lime and fertilisers. The maintenance of plant cover at such sites minimises soil erosion and reduces contamination from wind-blown dust. It has... 

Contaminants in ambient air result in inhalation exposure either when the child is outdoors and breathes contaminated air or when contaminants in the air are transported indoors where the child spends time. Adverse health effects (acute and chronic) associated with inhalation of air contaminants are a common concern for people living in polluted cities, near hazardous waste sites, or close to point sources like smelters (Figure 15). Air emissions from past or current production processes, as well as volatilization of organic compounds, airborne particulates, and acid gases, may expose residents to contaminants at levels of health concern (ATSDR, 1994). In urban areas, mobile sources contribute substantially to organic, inorganic, and particulate air pollution. Fires, open burning, and wind-blown dust can also be major sources of ambient air pollution. 

To solve the above mentioned problems various tasks are often included within interface modules, as well as data interpolation, meteorological fields downscaling, boundary layer parametrizations and estimation of dispersion coefficients, evaluation of meteorological driven emissions (e.g. biogenic, wind blown dust, sea salt), enhancement of physiographic data. 

A big learning was that it is best to have as much of the emissions inventory as possible on-line, described by algorithms that respond where appropriate to the forecast meteorology, and calibrated by relevant observational data. We now have emissions from motor vehicles, vegetation (Azzi et al. 2005 Kirstine and Galbally 2004), soils, wind-blown dust, bushfires, sea-salt spray, domestic wood heating, and some industry handled this way. 

Australia-wide forecasts are now done for wind-blown dust (e.g., Wain et al. 2006) and for bushfire smoke. Size-segregated dust is emitted and transported depending on historical land-use, soil-type and seasonal leaf area index (LAI). For bushfires, we use the Sentinel outputs of hotspots to locate emissions. Sentinel currently obtains MODIS data from the NASA EO Satellites Terra and Aqua (see http //sentinel2.ga.gov.au/acres/sentinel). 

The budgets of the separate boxes are discussed first. Concerning the continental atmosphere it is, to begin with, subdivided into three smaller boxes, i.e., the atmosphere over industrial and urban regions, dusty continental atmosphere, meaning arid regions hit by wind blown dust, and clean continental atmosphere. 

Table 7 represents the opinion of the authors that the importance of wind blown dust has earlier been underestimated. Their own conclusions indicate that in the budget of the atmosphere, the wind blown dust should be considered as an entry of 20 Tg y . ... 

Substantial transport of wind-blown dust has occurred during the arid phases that have periodically characterised the climate of southern Australia in the Quaternary (Bowler, 1976, 1982 Colhoun, 1991). The palaeomagnetic minimum age for the "red earths" in the cave at Buchan suggests that these wind-blown sediments record a period of aridity older than 780 ka. Although the most intense periods of aridity in southern Australia occurred during the last 700 000 years (Bowler, 1982), seasonal aridity became established at about 6 Ma, and progressive desiccation was well advanced by 2.5 Ma (Bowler, 1976). In central Australia the onset of arid-zone aeolian facies may have been at around 1.1 Ma (Chen and Barton, 1991). Thus the "red earths" at Buchan appear to record the early imprint of these climatic changes on southern Australia, probably in the early Pleistocene. 

Mortar/membrane mixed with foreign material, such as wind-blown dust, or sand. (2)... 

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