Particulate matter, description

Particulate matter is a complex emission that is classified as either suspended particulate matter, total suspended particulate matter, or simply, particulate matter. For human health purposes, the fraction of particulate matter that has been shown to contribute to respiratory diseases is termed PMio (i.e., particulate matter with sizes less than 10 tim). From a control standpoint, particulate matter can be characterized as follows (1) particle size distribution and (2) particulate matter concentration in the emission (mg/m ). On occasion, physical property descriptions may also be employed when there are specific control applications. 

Specific research subjects have emerged with respect to improved descriptions of specific phenomena. Some time ago, it was speculated that gas-solid interactions and turbulence effects on reaction kinetics would be important areas of advance in the modeling art. Gas-solid interactions include both chemical formation of aerosols and reactions on surfaces of pre-existing suspended particulate matter. Because of differing effects of a material in the gas phase and in some condensed phase, it will be important to characterize transformation processes. The achex (Aerosol Characterization hYperiment) program recently carried out under the direction of Hidy will provide an extensive data base with which to test new ways of treating the gas-solid interaction problem. 

Although ophthalmic drug products can be considered topical products, they have been grouped here with inject-ables because they are required to be sterile (21 CFR 200.50(a)(2)) and the descriptive, suitability, and quality control information is typically the same as that for an injectable drug product. Because ophthalmic drug products are applied to the eye, compatibility and safety should also address the container closure system s potential to form substances which irritate the eye or introduce particulate matter into the product (see USP <771> Ophthalmic Ointments). 

Further description of photochemical processes in the atmospheric aqueous phase and on particulate matter is included in our recent review [28]. 

When a column of particulate matter is flooded with water and then allowed to drain, several important points must be considered. The water in excess of the amount the particles are able to retain is called gravitation water. The water retained is called capillary water. The amount of water retained depends upon the effect of gravitational forces and the surface tension. Briggs (1897) has given what is probably the best description of gravitation and capillary waters, and the following is quoted from his investigation of the subject ... 

Binkowski F. S. and Shankar U. (1995) The regional particulate matter model 1. Model description and preliminary results. J. Geophys. Res. 100, 26191—26209. 

The model system allows also a basin wide description of the transport of suspended particulate matter (SPM), which can be transported near the seabed within the so-called fluffy layer and is strongly affected by surface waves in coastal waters. Understanding the settling and resuspension of SPM in response to waves and currents is of great importance to assess the transports of material discharged by rivers from the coastal regions to the final deposit in the sediments of central basins. 

By particulate matter we refer to any substance, except pure water, that exists as a liquid or solid in the atmosphere under normal conditions and is of microscopic or submicroscopic size but larger than molecular dimensions. Among atmospheric constituents, particulate matter is unique in its complexity. Airbome particulate matter results not only from direct emissions of particles but also from emissions of certain gases that either condense as particles directly or undergo chemical transformation to a species that condenses as a particle. A full description of atmospheric particles requires specification of not only their concentration but also their size, chemical composition, phase (i.e., liquid or solid), and morphology. 

Terms often used to describe the aerosol mass concentration include total suspended particulate matter (TSP) and PM (particulate matter with diameter smaller than. v pm). TSP refers to the mass concentration of atmospheric particles smaller than 40 to 50 /xm, while PM 2.5 and PMio are routinely monitored. For a description of the sampling issues and problems related to the measurement of TSP, PM 2.5, and PM 10 the reader is referred to the EPA Particulate Matter Criteria document (U.S. EPA, 1996). 

A description and prediction of particulate matter distribution in water are of great direct importance for the assessment of water quality in the broadest sense. The term particulates is used to summarize suspended inorganic and organic particles in that order of size where interparticle forces become important. For all practical purposes particulate matter in natural water consists mainly of the different clay fractions (kaolinite, montmorillonite, illite, etc.) of metal oxides and of... 

In 1988, directive 80/1107/EEC was amended for the last time by EU directive 88/642/EEC [6-4]. It contained several additions concerning the procedure for exposure measurements and setting occupational limit values. The newly implemented annex Ila contained important and useful information on the updated definition of particulate matter (dust, fume, and mist) and on the exposure measurement strategy, with detailed descriptions of sampling conditions, especially for dusts. 

By measuring concentration ratios, environmental phase distributions for chemicals can be empirically determined and characterized, both in the field and the laboratoiy. Examples are sorption coefficients Kd between water and soil or sediment solids or coefficients Kp describing the distribution between the gas phase and atmospheric particulate matter. Going beyond such empirical descriptions requires the derivation of relationships of general validity that allow the quantitative description of phase distributions involving environmental chemicals or enviromnental phases for which no such empirical data exist. 

Major considerations in the treatment of beverage wastewaters are the presence of large particulate matter in suspension and the fluctuations in hydraulic and organic loads. The following is a brief description of the wastewater from each pretreatment group ... 

Description— These devices provide air to the wearer through a small-diameter, high-pressure hose line from a source of uncontaminated air. The source is usually derived from a compressed airline with a valve in the hose to reduce the pressure. A filter must be included in the hose line (between the compressed airline and the respirator) to remove oil and water mists, oil vapors, and any particulate matter that may be present in the compressed air. Internally lubricated compressors require that precautions be taken against overheating, as the heated oil will break down and form carbon monoxide. Where the air supply for airline respirators is taken from the compressed airline, a carbon monoxide alarm must be installed in the air supply system. Completion of a prior-to-operation preventive maintenance check on the carbon monoxide alarm system is critical. 

General Description. Solid particle erosion (SPE) is the loss of surface material that results from repeated impacts of small, solid particles. In some cases SPE is a useful phenomenon, as in sandblasting and highspeed abrasive waterjet cutting, but it is a serious problem in many engineering systems, including steam and jet turbines, pipelines and valves carrying particulate matter, and fluidized bed combustion systems. 

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