Particulate matter distribution

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... 

Moments of a distribution often provide information that can be used to characterize particulate matter. Theyth moment of the population density function n is defined as... 

Although it is entirely possible for erosion-corrosion to occur in the absence of entrained particulate, it is common to find erosion-corrosion accelerated by a dilute dispersion of fine particulate matter (sand, silt, gas bubbles) entrained in the fluid. The character of the particulate, and even the fluid itself, substantially influences the effect. Eight major characteristics are influential particle shape, particle size, particle density, particle hardness, particle size distribution, angle of impact, impact velocity, and fluid viscosity. 

Distribution of Cities by Population Class and Particulate Matter Concentration, 1957-1967... 

The three major characteristics of particulate pollutants in the ambient atmosphere are total mass concentration, size distribution, and chemical composition. In the United States, the PM q concentration, particulate matter with an aerodynamic diameter <10 /nm, is the quantity measured for an air quality standard to protect human health from effects caused by inhalation of suspended particulate matter. As shown in Chapter 7, the size distribution of particulate pollutants is very important in understanding... 

The most common monitoring of particulate matter is for light attenuation (opacity). Less frequently used methods exist for monitoring mass concentration, size distribution, and chemical composition. 

Airborne particulate matter, which includes dust, dirt, soot, smoke, and liquid droplets emitted into the air, is small enough to be suspended in the atmosphere. Airborne particulate matter may be a complex mixture of organic and inorganic substances. They can be characterized by their physical attributes, which influence their transport and deposition, and their chemical composition, which influences their effect on health. The physical attributes of airborne particulates include mass concentration and size distribution. Ambient levels of mass concentration are measured in micrograms per cubic meter (mg/m ) size attributes are usually measured in aerodynamic diameter. Particulate matter (PM) exceeding 2.5 microns (/i) in aerodynamic diameter is generally defined as coarse particles, while particles smaller than 2.5 mm (PMj,) are called fine particles. 

Particle size distribution A method of relating the size or weight of particulate matter, e.g., 50% with diameters in the... 

All comhustion processes produce particulate matter. Amounts and size distribution of the particulates emitted depend on a number of factors, including fuel burned, type ofboiler, and effectiveness of collection devices. 

The deposition velocities depend on the size distribution of the particulate matter, on the frequency of occurrence and intensity of precipitation, the chemical composition of the particles, the wind speed, nature of the surface, etc. Typical values of and dj for particles below about 1 average residence time in the atmosphere for such particles is a few days. 

Bacon MP, Spencer DW, Brewer PG (1976) Pb-210/Ra-226 and Po-210/Pb-210 disequilibria in seawater and snspended particulate matter. Earth Planet Sci Lett 32 277-296 Bacon MP, Anderson RF (1982) Distribution of thorium isotopes between dissolved and particulate forms in the deep sea. J Geophys Res 87 2045-2056... 

Baskaran and Santschi (1993) examined " Th from six shallow Texas estuaries. They found dissolved residence times ranged from 0.08 to 4.9 days and the total residence time ranged from 0.9 and 7.8 days. They found the Th dissolved and total water column residence times were much shorter in the summer. This was attributed to the more energetic particle resuspension rates during the summer sampling. They also observed an inverse relation between distribution coefficients and particle concentrations, implying that kinetic factors control Th distribution. Baskaran et al. (1993) and Baskaran and Santschi (2002) showed that the residence time of colloidal and particulate " Th residence time in the coastal waters are considerably lower (1.4 days) than those in the surface waters in the shelf and open ocean (9.1 days) of the Western Arctic Ocean (Baskaran et al. 2003). Based on the mass concentrations of colloidal and particulate matter, it was concluded that only a small portion of the colloidal " Th actively participates in Arctic Th cycling (Baskaran et al. 2003). 

Cautreels W, VanCauwenberghe K. 1978. Experiments on the distribution of organic pollutants between airborne particulate matter and the corresponding gas phase. Atmos Environ 12 1133-1141. 

The vertical distribution of pollutants originates from water movements and sinking of organic particulate matter operating as carriers for lipophilic substances. PFOA enters ocean water exclusively in the surface level and instantaneously establishes... 

Laboratory sorption experiments are used to determine the distribution of a compound between the solid and liquid phases in the absence of other processes involved (e.g. biodegradation, precipitation) under controlled conditions. Sorption experiments are usually performed by adding particulate matter, free of surfactants, to solutions with different known surfactant concentrations at constant temperature (sorption isotherms). The experiments performed at high concentrations of... 

One aspect to be addressed in order to obtain a realistic vision of the toxicity of these kinds of compounds is their environmental behaviour. Surfactants tend to be adsorbed on particulate matter and thus subsequently to sediment. Consequently, the highest surfactant concentrations are found in sediments, although their distribution is dependent on the partitioning equilibrium between the substrate and interstitial water. This results in two possible routes for uptake (bioaccumulation) and effect. The relative importance of each of these routes depends on the special habits of each benthic organism. 

It influences the distribution of substances between the aqueous phase and particulate matter, which, in turn, affects their transport through the various reservoirs of the earth. The affinity of the solutes to the surfaces of the "conveyor belt" of the settling inorganic and biotic particles in the ocean (and in lakes) regulate their (relative) residence time, their residual concentrations and their... 

In natural waters and soil and sediment systems one needs to distinguish analytically between dissolved and particulate material. Fig. 7.1 classifies various types of particulate and dissolved materials. Obviously, operational distinguishing (e.g., based on filtration or centrifugation) between "dissolved" and "particulate" matter merely by filtration is often not able to discriminate between particles and solutes, because size distribution of aquatic components vary in a continuous matter from Angstroms to microns. 

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. 

One hint of possible trouble to come is provided by the information we described in Chapter 4, related to airborne particulate matter (PM). The available evidence ascribes significant increases in the risks of asthma and other respiratory diseases, certain cardiovascular conditions, and lung cancer to PM exposure, particularly those that average less than 2.5 pm (2500 nm) in size. As we noted, the chemical composition of these particles varies widely, depending upon source, but may not be as important as particle size as a risk determinant. Moreover, there is some experimental evidence pointing to the so-called ultra-fines, PM with dimensions below 100 nm, as significant contributors to PM risk. In addition some experimental studies have demonstrated that ultrafines not only distribute themselves throughout the airways, but seem to be able to translocate to other parts of the body - liver, heart, perhaps the CNS. 

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