Matter particulate

Particulate air pollutants arise from many sources, including natural ones. These include 

Combustion of any kind produces toxic particulate matter, smoke. The combustion can be natural such as a lightning-induced forest fire or unnatural such as the burning of fossil fuel for energy production, a petroleum refinery or plastics warehouse fire)22-23 In addition to particulates, fires produce PAHs, carbon monoxide, organic and inorganic cyanides, and free radicals that are toxicJ24-25  

Tobacco smoke. Tobacco smoke produces particulate matter that acts as an adsorption site for toxic vapors)26 In addition to particulates, tobacco smoke produces more than 4000 individual toxic compounds, including 43 known carcinogens. 27 Many of the toxic effects of tobacco smoke that have been established empirically cannot be ascribed to individual compounds in that smoke. With more than 4000 different toxins, the number of mixtures possible is incalculable. Numerous examples of synergism between tobacco smoke and other toxicants have been identified. These include tobacco smoke and asbestos or other mineral fibers, I28 29 alcohol, I30 31 organic solvents, 32 biological 

Volcanoes Volcanoes are natural events that result in the release of huge quantities of particulates into the atmosphere. I35 On May 18, 1980, Mount Saint Helens, in Washington state, erupted violently. Volcanic ash expelled during the eruption was of respirable size and resulted in a large number of respiratory injuries to those exposed J36  

Particulate matter in polluted air presents a mixture hazard that exceeds its own toxicology. I37l When lodged in the lungs particles can act as adsorption sites for inhaled vapors and mists. Carbon black is an example of such a particulate. Carbon readily adsorbs hydrocarbons, including PAHs, on its surface and retains these toxicants in the lungs for periods of time far exceeding their usual residence time. Asbestos, too, acts as an absorption site for other toxicants. 

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. 

Particulate matter is the term used to describe solid particles and liquid droplets found in the atmosphere. Particulates are produced by a host of natural and anthropogenic sources. Mist and fog are both forms of natural particulates, as are windblown soil, dust, smoke from forest fires, and biological objects, such as bacteria, fungal spores, and pollen. The incomplete combustion of fossil fuels is one of the most important anthropogenic (human-made) sources of particulates. Such processes release unhurned carbon particles, oxides of sulfur and nitrogen, and a host of organic compounds into the air. 

The particles and droplets that make up particulate matter range widely in size. Some are large enough to he seen, such as the tiny particles of sand stirred up in a dust storm. Others are so small as to be invisible to the naked eye. In general, these particles and droplets are divided into two major categories, based on their size. Particles designated as PM2 5 have diameters less than or equal to 2.5 p (microns or micrometers) in diameter. Particles with diameters between 2.5 p and 10 p are designated as PMj particulates. The terms fine and coarse are sometimes used to described PM2 5 and PMjq particulates, respectively. 

Particulates are also classified as to their mode of formation. Some, designated sls primary particulates, are released directly to the atmosphere in the form of tiny particles or droplets. Droplets of salt and water blown off the surface of the ocean are examples of primary particulates. Other particulates are formed in the atmosphere as a result of chemical and/or physical reactions. For example, sulfur 

EPA has collected data on the emission of PM2 5 particulates since 1992 and on air quality for the pollutant since 1999. These data indicate that the direct emission of PM2 5 particles has decreased about 10 percent over the monitoring period, from about 2.75 million short tons (2.5 million metric tons) in 1992 to about 2.4 million short tons (2.2 million metric tons) in 2001. Over the short span of monitoring, PM2 5 concentration decreased by about 5 percent from about 14 pg/m in 1999 to about 13.3 pg/m in 2001. 

A relatively small amount of particulates with diameters of less than 10 p are able to penetrate more deeply into the respiratory system, blocking the capillaries and alveoli of the lungs. When this happens, a number of health problems may result. The severity of those 

1 Particulate Matter. - Exposure to respirable particulate matter of 10 pm diameter (PMio) has been estimated to be responsible for 6% of all deaths in Europe and to contribute significantly to morbidity. The principal source of air-borne particulate material is combustion. Dellinger and colleagues have examined by EPR extracts from samples of fine particulates (PM2.5) collected from cities across the United States. They detected stable signals from semiquinone species, believed to be derived from polyaromatic hydrocarbons. Incubation of the extracts with DNA led to strand breakage, which was proposed to be due to reduction of oxygen to 02- by the semiquinones, followed by conversion to the OH radical. Diesel exhaust particles (DEP), which contain 

The emission range of particulate matter is very wide. Particulate emissions depend primarily on the cupola type used, as shown in Table 3.3  

Cupola type Dust emission (kg/tonne metal charge) Coke proportion (kg/tonne metal charge) 

Dust emission levels measured at the stack for three German furnaces are given in Table 3.4. 

Flue-gas cleaning Volume (m /h) Total dust (mg/m ) PMio (%) PM25 (%) 

In general, particle sizes range from less than 1 pm up to 10 mm, with 50 % less than 100pm. However, 5 to 20 % are smaller than 2 pm, which makes the dust collection more difficult. Cupola dust is primarily made up of coke, silica, rust and limestone, as shown in Table 3.5. 

The sample solutions injected into an ion chromatographic system must be free of particulate matter to avoid plugging of the capillary connecting tubing and the frits at the head of the analytical column. Even samples that appear to be clear may contain unsuspected fine particles. It is more or less standard procedure to filter sample solutions prior to their injection. Disposable membrane filters with a pore diameter of 

45 pm are sufficient in most cases. Samples with biological activity are filtered through asceptic filters with a pore diameter of 0.22 pm to avoid a change in sample composition due to bacterial oxidation or reduction. In general, membrane filters should be rinsed with de-ionized water prior to use to avoid sample contamination. 

Neither Table 2-1 nor Table 2-2 lists among the constituents of the air the suspended particulate matter that it always contains. The gases and vapors exist as individual molecules in random motion. Each gas or vapor 

Conversion Factors between Volume and Mass Units of Concentration (25°C, 760 mm Hg) 

Before the advent of humans and their works, there must have been particles in the air from natural sources. These certainly included all the particulate forms of condensed water vapor the condensed and reacted forms of natural organic vapors salt particles resulting from the evaporation 

The majority of particles in the atmosphere are spherical in shape because they are formed by condensation or cooling processes or they contain core nuclei coated with liquid. Liquid surface tension draws the material in the particle into a spherical shape. Other important particle shapes exist in the atmosphere e.g., asbestos is present as long fibers and fly ash can be irregular in shape. 

The methods just noted tell something about the physical characteristics of atmospheric particulate matter but nothing about its chemical composition. One can seek this kind of information for either individual particles or all particles en masse. Analysis of particles en masse involves analysis of a mixture of particles of many different compounds. How much of 

The main sources of air pollution from petroleum refineries are listed in Table 1. Refineries can be significant sources of particulate matter (PM), which can irritate the respiratory tract. PM is especially harmful when it is associated with sulfur and nitrogen oxides (SOx and NOx). 

ArterberryJD, Durham WF, ElliottJW, Wolfe HR Exposure to parathion—measurement by blood cholinesterase level and urinary -nitro-phenol excretion. Arch Environ Health 3 476-485, 1961 

Spear RC, et ah Worker poisonings due to paraoxon residues. J Occup Med 19 411-414, 1977 

lARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans, Vol 30, Miscellaneous pesticides, pp 153-181. Lyon, International Agency for Research on Cancer, 1983 

Toxicology. Epidemiological studies have consistently found an association between small increases in urban PM and health effects, including increased morbidity and mortality in people with respiratory and cardiac disease.  

Particulate matter air pollution is especially harmful to people with lung disease such as asthma and chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema, as well as people with heart disease. Exposure to particulate air pollution can trigger asthma attacks and cause wheezing, coughing, and respiratory irritation in individuals with sensitive airways. It was estimated in one major study that the excess risk of total mortality is 6.2% per each increase in 10pgPM2.s/m and 9.3% for cardiopulmonary mortality.  

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This experiment describes the construction of an air sampler using an aquarium pump, a flow meter, a filter holder, and bottles that serve as traps for analytes. Applications include the determinations of SO2, NO2, HCHO, and suspended particulate matter. 

To examine a sample by inductively coupled plasma mass spectrometry (ICP/MS) or inductively coupled plasma atomic-emission spectroscopy (ICP/AES) the sample must be transported into the flame of a plasma torch. Once in the flame, sample molecules are literally ripped apart to form ions of their constituent elements. These fragmentation and ionization processes are described in Chapters 6 and 14. To introduce samples into the center of the (plasma) flame, they must be transported there as gases, as finely dispersed droplets of a solution, or as fine particulate matter. The various methods of sample introduction are described here in three parts — A, B, and C Chapters 15, 16, and 17 — to cover gases, solutions (liquids), and solids. Some types of sample inlets are multipurpose and can be used with gases and liquids or with liquids and solids, but others have been designed specifically for only one kind of analysis. However, the principles governing the operation of inlet systems fall into a small number of categories. This chapter discusses specifically substances that are normally liquids at ambient temperatures. This sort of inlet is the commonest in analytical work. 

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. 

In operation, a spark source is normally first flushed with argon to remove loose particulate matter from any previous analysis. The argon flow is then reduced, and the cathode is preheated or conditioned with a short bum time (about 20 sec). The argon flow is then reduced once more, and the source is ran for sufficient time to build a signal from the sample. The spark is then stopped, and the process is repeated as many times as necessary to obtain a consistent series of analyses. The arc source operates continuously, and sample signal can be taken over long periods of time. 

An aerosol produced instrumentally has similar properties, except that the aerosol is usually produced from solutions and not from pure liquids. For solutions of analytes, the droplets consist of solute and solvent, from which the latter can evaporate to give smaller droplets of increasingly concentrated solution (Figure 19.1). If the solvent evaporates entirely from a droplet, the desolvated dry solute appears as small solid particles, often simply called particulate matter. 

The calculation shows how rapidly a droplet changes in diameter with time as it flows toward the plasma flame. At 40°C, a droplet loses 90% of its size within alxtut 1.5 sec, in which time the sweep gas has flowed only about 8 cm along the tube leading to the plasma flame. Typical desolvation chambers operate at 150°C and, at these temperatures, similar changes in diameter will be complete within a few milliseconds. The droplets of sample solution lose almost all of their solvent (dry out) to give only residual sample (solute) particulate matter before reaching the plasma flame. 

Some solid materials are very intractable to analysis by standard methods and cannot be easily vaporized or dissolved in common solvents. Glass, bone, dried paint, and archaeological samples are common examples. These materials would now be examined by laser ablation, a technique that produces an aerosol of particulate matter. The laser can be used in its defocused mode for surface profiling or in its focused mode for depth profiling. Interestingly, lasers can be used to vaporize even thermally labile materials through use of the matrix-assisted laser desorption ionization (MALDI) method variant. 

The aerosol is swept to the torch in a stream of argon gas. During passage from the nebulizer to the plasma flame, the droplets rapidly become smaller, as solvent evaporates, and evenmally become very small. In many cases, almost all of the solvent evaporates to leave dry particulate matter of residual analyte. 

After desolvation, the remaining fine particulate matter and residual droplets are swept by the argon carrier into the plasma flame, where fragmentation and ionization occur. 

For mass spectrometric analysis of an analyte solution using a plasma torch, it is necessary to break down the solution into a fine droplet form that can be swept into the flame by a stream of argon gas. On the way to the flame, the droplets become even smaller and can eventually lose all solvent to leave dry analyte particulate matter. This fine residual matter can be fragmented and ionized in the plasma flame without disturbing its operation. 

Bacterial Endotoxias Test (85)," "Biological Reactivity Tests, in vivo (88)," "Particulate Matter ia Injections (788)," and "Purified Water," JJSP 23 The U.S. Pharmacopeia Convention, RockviUe, Md., 1994. 

Increases in the appHed static pressure increase the acoustic intensity necessary for cavitation, but if equal number of cavitation events occur, the coUapse should be more intense. In contrast, as the ambient pressure is reduced, eventuaUy the gas-fiUed crevices of particulate matter which serve as nucleation sites for the formation of cavitation in even "pure" Hquids, wiU be deactivated, and therefore the observed sonochemistry wiU be diminished. 

Environmental Aspects. Airborne particulate matter (187) and aerosol (188) samples from around the world have been found to contain a variety of organic monocarboxyhc and dicarboxyhc acids, including adipic acid. Traces of the acid found ia southern California air were related both to automobile exhaust emission (189) and, iadirecfly, to cyclohexene as a secondary aerosol precursor (via ozonolysis) (190). Dibasic acids (eg, succinic acid) have been found even ia such unlikely sources as the Murchison meteorite (191). PubHc health standards for adipic acid contamination of reservoir waters were evaluated with respect to toxicity, odor, taste, transparency, foam, and other criteria (192). BiodegradabiUty of adipic acid solutions was also evaluated with respect to BOD/theoretical oxygen demand ratio, rate, lag time, and other factors (193). 

B. W. Loo, J. M. JaMevic, and F. S. Goulding, "Dichotomous Virtual Impactors for Large Scale Monitoring of Airborne Particulate Matter," in B. Y. H. Liu, ed., Eine Particles, Aerosol Generation, Measurement, Sampling and Analysis, Academic Press, Inc., New York, 1976, pp. 311—350. 

E. Bakke, "The AppHcation of Wet Electrostatic Precipitators for Control of Eiue Particulate Matter," Preprint, Symposium on Control of Tine Particulate Emissions from Industrial Sources, Joint U.S.-USSR Working Group, Stationay Source Air Pollution ControlTechnology, San Francisco, Calif, Jan. 15—18, 1974. 

Extrusion. The filtered, preheated polymer solution is deHvered to the spinneret for extmsion at constant volume by accurate metering pumps. The spinnerets are of stainless steel or another suitable metal and may contain from thirteen to several hundred precision-made holes to provide a fiber of desired si2e and shape. AuxUiary filters are inserted in front of the fixture that holds the spinneret and in the spinneret itself to remove any residual particulate matter in the extmsion solution. 

Use of ultrafiltration (UF) membranes is becoming increasingly popular for clarification of apple juice. AH particulate matter and cloud is removed, but enzymes pass through the membrane as part of the clarified juice. Thus pasteurization before UF treatment to inactivate enzymes prevents haze formation from enzymatic activity. Retention of flavor volatiles is lower than that using a rack-and-frame press, but higher than that using rotary vacuum precoat-filtration (21). 

Traditional appHcations for latices are adhesives, binders for fibers and particulate matter, protective and decorative coatings (qv), dipped goods, foam, paper coatings, backings for carpet and upholstery, modifiers for bitumens and concrete, and thread and textile modifiers. More recent appHcations include biomedical appHcations as protein immobilizers, visual detectors in immunoassays (qv), as release agents, in electronic appHcations as photoresists for circuit boards, in batteries (qv), conductive paint, copy machines, and as key components in molecular electronic devices. 

Binders. Latices are used as fiber binders by the paper and textile industries. The two principal methods of appHcation are (/) wet-end addition, wherein the ionic latex is added to a fiber slurry and then coagulated in the slurry prior to sheet formation, and (2) saturation of the latex into a formed fiber web wherein the latex is coagulated by dehydration. Latices are also used as binders for particulate matter such as mbber scrap. 

Air-laid pulp-forming lines generally consist of three or more forming heads ia tandem. Liae widths range from 1 to 3 m and operate at speeds of some 400 m /min. Web weights range from 70 to 2000 g/m at throughputs of about 1000 kg/h. Air-laid pulp lines can be modified to process mixtures of textile and pulp fibers and to accommodate the addition of particulate matter. 

Plastic components can be leached into the product and the alkalinity also can be affected by certain types of glass (qv). Particulate matter can be introduced by flaking from container surfaces. The containers also must be able to withstand the heat and pressure of sterilization. 

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