Subject particulate matter

Suffice it to say at this stage that the surfaces of most solids subjected to such laser heating will be heated rapidly to very high temperatures and will vaporize as a mix of gas, molten droplets, and small particulate matter. For ICP/MS, it is then only necessary to sweep the ablated aerosol into the plasma flame using a flow of argon gas this is the basis of an ablation cell. It is usual to include a TV monitor and small camera to view the sample and to help direct the laser beam to where it is needed on the surface of the sample. 

Dry aerosols, or particulate matter, differ so much from the carrying gas stream that their removal should present no major difficulties. The aerosol is different physically, chemically, and electrically. It has vastly different inertial properties than the carrying gas stream and can be subjected to an electric charge. It may be soluble in a specific liquid. With such a variety of removal mechanisms that can be applied, it is not surprising that particulate matter, such as mineral dust, can be removed by a filter, wet scrubber, or electrostatic precipitator with equally satisfactory results. 

Samples of particulate matter can be subjected to many of the above analytical techniques in chemical characterization. The following methods are, however, particularly applicable to analysis of physical characteristics of particulate matter isolated from air sampling. 

Power plant emissions result from the comhustion of fossil fuels such as coal, gas, and oil. These emissions include sulfur dioxide (SO,), nitrogen oxides (NO.,), particulate matter, and hazardous air pollutants, all of which are subject to environmental regulations. Another emission is carbon dioxide (CO,), suspected of being responsible for global warming. 

This deals with all equipment used for the removal of particulate matter and represents a wide range of possibilities. Several books cover this subject and only a few typical examples are quoted here. 

Although the relationship of sediment adsorption to water concentration appears to be a controlling feature of shallow water systems such as lakes and coastal shelf water, the open ocean is more likely to contain soluble plutonium which seems to be unaffected by particulate matter. This is particularly evident in two oceanographic studies. Bowen et al have discovered a stratum of plutonium in the North Pacific at about 500m that has not changed depth appreciably from 1973 to 1980. How it arrived at this depth is subject to conjecture but it appears to be soluble plutonium which is not settling(17). Fukai et al have delineated plutonium maxima in the Mediterranean Sea which seem to be due to soluble species(18). Comparison of americium to plutonium ratios in this... 

Emissions from hazardous waste combustors are regulated under two statutory authorities RCRA and the CAA. The MACT standards set emission limitations for dioxins, furans, metals, particulate matter, total chlorine, hydrocarbons/carbon monoxide, and destruction and removal efficiency (DRE) for organics. Once a facility has demonstrated compliance with the MACT standards by conducting its comprehensive performance test (CPT) and submitting its notification of compliance (NOC), it is no longer subject to the RCRA emission requirements with a few exceptions. RCRA-permitted facilities, however, must continue to comply with their permitted emissions requirements until they obtain modifications to remove any duplicative emissions conditions from their RCRA... 

This is a temporal study of personal exposures to particulate matter in a panel of patients with chronic obstructive pulmonary disease. Fifteen subjects will be monitored... 

In a continuous reformer, some particulate and dust matter can be generated as the catalyst moves from reactor to reactor and is subject to attrition. However, due to catalyst design little attrition occurs, and the only outlet to the atmosphere is the regeneration vent, which is most often scrubbed with a caustic to prevent emission of hydrochloric acid (this also removes particulate matter). Emissions of carbon monoxide and hydrogen sulfide may occur during regeneration of catalyst. 

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. 

Decabromodiphenyl ether (BDE-209) is a major industrial product from the polybrominated diphenyl ethers used as flame retardants derivatives of this product have been detected in the environment. After exposure to the land surface, these contaminants adsorb on soil materials and may reach the atmosphere as particulate matter these particulates are subsequently subject to photolytic reactions. In this context, Ahn et al. (2006) studied photolysis of BDE-209 adsorbed on clay minerals, metal oxides, and sediments, under sunhght and UV dark irradiation. Dark and light control treatments during UV and sunlight irradiation showed no disappearance of BDE-209 during the experiments. Data on half-lives and rate constants of BDE-209 adsorbed on subsurface minerals and sediments, as determined by Ahn et al. (2006) and extracted from the literature, are shown in Table 16.6. 

Janssen NAH et al Personal exposure to fine particulate matter in elderly subjects relation between personal, indoor, and outdoor concentrations. J Air Waste Manag Assoc 50(7) 1133-1143,2000... 

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