Particle airborne dust

Flying objects and particles, airborne dusts, splashing liquids, excessive light, and radiation may injure the eyes. People must have protection from these dangers. The same dangers may injure face or neck tissues. The dangers increase when materials are hot or can react chemically with human tissue. 

Toxicity concerns regarding beryUium result principally from possible consequences from inbaling its oxide. Any operation that produces airborne particles or dust of the oxide must be carried out using proper precautions to personnel. 

While the lung is the major organ exposed to airborne dusts, such agents may also be swallowed following mucociliary transport and removal from the lung. Contaminating particles contained in food and drink also gain direct access into the gut. 

The basic principle for 210Pb dating is that gaseous 222Rn is emitted to the atmosphere from the lithosphere, surface waters and airborne dust and there decays to 210Pb. After formation in the troposphere, 2l0Pb becomes attached to aerosol particles which reside in the atmosphere for only 30 days or less depending on season, latitude, frequency of rainfall, size and altitude of the aerosols, Nevissi et al., [17]1, Schell [26], and Poet et al., [19]. — —... 

Lacey (9) airborne dust opening area of all cotton mills 10% of particles 2% of particles 3 particles/m... 

Gram-negative Bacteria. The significant data are summarized in Table IV. Cinkotai et al. (11,12) showed that the prevalence of byssinotic symptoms correlated best with gram-negative rod counts in the total airborne dust from cardrooms of cotton mills. This correlation could be Increased by multiplying the bacterial counts by the years of exposure of the worker. These bacteria also correlated with the number of 2-4 ym particles and the amount of protease in the air. 

This tendency of increasing duration of correlation with decreasing particle size is illustrated in Fig. 7-20. This means, that the impact of smaller particles is more uniform than that of larger particles, which are deposited relatively quickly. Thus it is possible to characterize the long-term impact level of smaller airborne dust particulates. 

Here the reaction rate depends not only on the concentration of the S02 but also on the surface area of any catalyst available, such as airborne dust particles. The efficiency of a catalyst depends upon its specific surface area, Asp, defined as the ratio of surface area to mass [30], Accordingly, this property is frequently used as a basis for comparing different kinds of catalysts, or catalyst supports, and for diagnosing practical problems in catalysts being used in a process (since both agglomeration and poisoning reduce Asp). The specific surface area of the airborne dust particles, considering n spheres of density p and radius R, would be ... 

The sample of smaller particles has 1000 times more surface area. If they were airborne dust particles, with other factors being equal, the higher surface area sample would much more efficiently catalyze the S02 —t S03 reaction. 

The major drawbacks of the method are the possible loss of some elements by volatilization, contamination of the sample by airborne dust, as it must be left open to the atmosphere, and irreversible sorption of analyte into the walls of the vessel. It is important to do blanks with each batch of samples. Particles generated within the muffle furnace may be the cause of high or variable blanks. In this case the applicability of the method will depend on the level of analyte expected in the samples. A variable blank can be tolerated when the analyte level is substantially higher than the blank but not when the concentration analyte found in the blank and the sample are similar. 

Inhalation and direct skin contact are the most common routes of chemical exposure. The greatest exposure risk in handling potent compounds in an analytical laboratory therefore occurs when handling solid materials due to the potential to generate and inhale airborne dust particles of the compound. Once the potent material has been placed into solution, the airborne exposure risk is reduced and solutions of potent compounds may be handled in a manner similar to other nonpotent pharmaceutical compounds, assuming good laboratory practices are followed. Caution should be taken not to aerosolize the solutions since this could create an inhalation hazard. In addition, any sample solution spills should be adequately cleaned to prevent powder deposits of the compound from forming, which could potentially become airborne after the liquid has dried. 

Soils that we encounter in maintaining a museum fabric collection are hand grime, airborn dust, and particles of fiber from the museum fabric itself. Because fabrics are by nature the best wiping material, museum fabrics, particularly cottons, pick up soils just as any wash cloth does. Therefore, all surfaces that are in contact with fabrics must be kept immaculately clean. 

An approximate formula sometimes used to estimate the settling velocity in feet per minute of airborne dust particles is... 

Particle size analysis of airborne dust is also necessary in the consideration of appropriate air-cleaning devices for use in a complete air-conditioning system at this site. All components of this air-conditioning system must be installed so that the architectural and artistic character of the tomb is not disrupted or endangered in any way. 

Beautiful blue skies and pink-color sunsets are direct consequences of the existence of an atmosphere. Sunlight scattered by gaseous molecules around our planet is responsible for the blue color of the sky. When we look at sunless sky, the light we observe is mainly scattered light. On the other hand, particulate matter also scatters light but toward the red side of the visible spectrum, and therefore small airborne dust particles produce a spectacular pink-reddish color. In this chapter we discuss the location, composition, and some properties of our atmosphere. 

The problems of the presence of PGMs in various environmental compartments and human exposure to them have been discussed in numerous review articles and books. [2-8, 10-13, 189]. We describe analytical approaches to the evaluation of the content of Pt, Pd, and Rh in plants, airborne particles and dusts, and soils and sediments, which are the most often examined materials for such purposes. 

Evaluation of the content of PGMs in airborne particles and dusts is important because of the possibility of their inhalation and accumulation in human lungs. Nanoparticles from autocatalysts can be transported into various parts of the environment (waters, plants, soils, and sediments) and transformed into more bioavailable species. There are data on the higher solubility of platinum from tunnel dusts than from inorganic species emitted from converters [30]. Distribution and accumulation of metals depend on traffic density, distance from the road, and meteorological conditions (wind, rain). The age of an autocatalyst and speed conditions directly affect the amount of nanoparticles released from catalytic... 

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