Particulate concentrations

Sampling of Particulates. Ambient air suspended particulate concentration was traditionaUy measured gravimetricaUy over a 24-h period with a "Hi-Vol" sampler. However, in 1987 the EPA changed ambient particulate control to the PM q reference method (24). In the PM q method, a... 

Low levels of particulates or potential poisons can sometimes be tolerated without a dramatic decrease in performance. Generally it has been recommended that the maximum particulate concentration not exceed 115 mg/m and that the maximum poison concentration not exceed 25 ppm (14). 

The most frequently used reference guidelines for ambient particulate concentration are those of WHO, the EU, and the USEPA. These guidelines are based on clinical, toxicological, and epidemiologic evidence and were established by determining the concentrations with the lowest observed adverse effect (implicitly accepting the notion that a lower threshold exists under which no adverse human... 

The main objective of air quality guidelines and standards is the protection of human health. Since fme particulates (PM,) are more likely to cause adverse health effects than coarse particulates, guidelines and standards referring to fine particulate concentrations are preferred to those referring to TSP, which includes coarse particulate concentrations. Scientific studies provide ample evidence of the relationship between exposure to short-term and long-term ambient particulate concentrations and human mortality and morbidity effects. However, the dose-response mechanism is not yet fully understood. Furthermore, according to the WHO, there is no safe threshold level below which health damage does not occur. 

P99 Other Physical Treatment milligrams of chemical/kilogram of air for particulates in air. If you have particulate concentrations (at standard... 

Procedure A sharp-edged nozzle is positioned in the duct, facing into the moving gas stream, and a gas sample is extracted isokinetically (see later) for a measured period of time. To allow for nonuniformity of particulate concentration in the duct, samples are taken at preselected positions in the duct cross-section. The particulate concentration is calculated from the weighed particulate mass and the gas sample volume. Figure 13.39 shows the measuring arrangement. 

Sampling Points To obtain a representative result, the gas normally has to be sampled at more than one point in the sampling plane, depending on the sampling plane area. This plane is usually divided into equal areas at the centers at which gas is extracted. To determine the particulate concentration in the plane, the nozzle is moved from one sampling point to the other. 

Particle counters A manual or automatic device used to determine the particulate concentration of a given gas sample. 

Particulate concentration The concentration of one or more particulates in a given quantity of a gas. 

Electrostatic precipitators (ESP) and wet gas scrubbers (WGS) are widely used to remove particulates from the FCC flue gas. Both can recover over 80% of filtrable solids. An ESP (Figure 10-6) is typically installed downstream of the flue gas heat recovery (prior to atmospheric discharge) to minimize particulate concentration. If both low particulate and low SO requirements are to be met, a wet gas scrubber such as Belco s (Figure 10-7) should be considered. If SO removal... 

Table 16-7 The surface or enzyme-catalyzed reaction rate constant, Mn/ for oxidation of Mn normalized for oxygen concentration [O2], pH and particulate concentration [X]. d[Mn ]/dt = Mn [Mn][02][0H] [X]...

Figure 3. The concentration of nranium (nM) versns salinity on the Amazon Shelf with an ideal dilntion line drawn throngh the riverine and seawater end members. Removal of dissolved U is evident at salinities that range from 0 to 16. The bottom illustration shows as a function of salinity for the same waters on the Amazon Shelf. A seawater value (144 0.2) is rapidly reached at a salinity of 4 during estuarine mixing. The high turbidity zone of the water colurtm is defined by the greatest suspended particulate concentrations. Data from Swarzenski et al. (2003).

The other metals exhibit different vertical profiles. The dissolved concentrations of Pb and Cu do not exhibit subsurface concentration maxima and, hence, do not appear to undergo any redox reactions. Their dissolved concentrations decline with increasing depth and are likely controlled by precipitation into sulfide minerals as the particulate concentrations increase rapidly with depth in the anoxic zone. In the anoxic waters, sulfide is supplied by in situ sulfate reduction. 

Vertical profiles of O2 and particulate and dissolved trace metal concentrations at 32.5°E and 44.5°N in the Black Sea. (a) Temperature, salinity, fluorescence, and O2 (b) ammonium, silica, nitrate+nitrite, and phosphate (c) Fe (d) Mn (e) Co (f) Pb (g) Cu (h) Zn (I) Cd and Ni. In the trace metal profiles, the dissolved concentrations are represented as solid circles, the total particulate concentrations by open circles, the acid-leachable particulate concentrations by open squares, and the suspended particulate matter concentrations by the solid triangles. Source-. After Tankere, S. P. C., et al. (2001). Continental Shelf Research, 21, 1501-1532. 

A third type of profile is exhibited by Ni in which a dissolved concentration maximum is positioned at the top of the anoxic layer with no overlying particulate concentration maximum. It is not clear what process(es) are supporting this. 

All of these factors may influence cotton particulate concentrations and visible light reflectance properties. Thus, using cottons with the natural range of variables for this feasibility study should add credence to the observed trends in the data. 

Particulate Burdens and Refectance Data. Table I gives the particulate concentrations. Percentage trash reported in Table I reflects nonlint trash only. These trash values are not positively biased by the lint entrainment associated with the so-called Shirley analyzer visible trash concentrations 9). 

For comparison purposes, regression parameters were computed for the model defined by Equations 6, 7, 8, and 10 and the model obtained by replacing In (1/R) in those equations by R. The dependent variable (y) is particulate concentration because it is desired to predict particulate content from reflectance values. Data from Tables I and II were also fitted to exponential and power functions where the independent variable (x) was reflectance but the fits were found to be inferior to that of the linear relationship. 

Wolff GT, Korsog PE. 1985. Estimates of the contributions of sources to inhalable particulate concentrations in Detroit. Atmos Environ 19(9) 1399-1409. 

Individuals whose jobs expose them to unusually high particulate concentrations are especially susceptible to health problems from the pollutant. For example, men and women who work with the mineral asbestos are very prone to development of a serious and usually fatal condition known as asbestosis, in which fibers of the mineral become embedded in the interstices (the empty spaces within tissue) of the lung. Similar conditions are observed among coal workers who inhale coal dust (pneumoconiosis, or black lung disease) textile workers (byssinosis, or brown lung disease) those who work with clay, brick, silica, glass, and other ceramic materials (silicosis) and workers exposed to high levels of beryllium fumes (berylliosis). 

One place this problem has become especially severe is the nation s national park system. Visitors to national parks have found their enjoyment of the natural scenery compromised by poor air quality that leaves famous and noteworthy features only barely visible. For this reason, one section of the 1977 Amendments to the Clean Air Act provided for a program of monitoring and pollution control in the nation s 156 national parks and wilderness areas. Poor visibility resulting from high particulate concentration has safety effects also. Automobile drivers and airline pilots may find that they are able to see shorter distances and less clearly, increasing the likelihood of accidents involving other vehicles and aircraft. 

Wlltsee, K. W., Jr. Cogley, D. R. "Analysis of Total Suspended Particulate Concentration In Metropolitan Boston", Walden Division of Abcor, Inc., June, 1977. 

Kleinman, M. T., T. J. Kneip and M. Eisenbud. Seasonal patterns of airborne particulate concentrations in New York City. Atmos. Environ. 10 9-11 (1976). 

Hall, S.R., Evaluation of Particulate Concentrations with Collecting Apparatus, Analytical Chemistry. 1952, 24, 996-1000. 

In order to obtain quantitative data on particulate air quality in the Owens Valley, a study sponsored by the California Air Resources Board was conducted by the Air Quality Group at UCD. The primary objective was to determine the impact of the dry lake bed on the average particulate concentration and on the dust storm particulate concentrations in the valley. In order to accomplish this, it was necessary to determine the elemental composition of the dry lake bed and to determine the average weekly and dust storm concentration of aerosols. 

Despite the benefits from stringent legislation and advances in environmental technology, the increase in the fleet of automotive vehicles and overpopulation in urban areas results in bad ah quality. It is estimated that up to 45% of Europe s urban population remains exposed to particulate concentrations above limit values, and up to 30% to ozone concentrations above target levels that assure human health protection. The concentrations of various pollutants in the atmosphere in various cities across Europe are shown in Table 1.4. The data in the table are from WHO s Healthy Cities Air Management Information System and the World Resources Institute, which relies on various national... 

Note that for the total (dissolved and particulate) concentration, Ct, the abrupt change of the solid-to-water-phase ratio, rsw (Eq. 9-15), at the sediment surface acts like a phase change. The numerical example given in Table 19.1 demonstrates that the transition from the open water column of a lake or the ocean to the sediments involves an increase of rsw by 5 to 6 orders of magnitude. Typically, in the open water, rs p is of order 10 3 kg m-3 while in the sediment column lies between 102 and 103 kg nr3. Thus, at equilibrium the total (dissolved and sorbed) concentration per unit bulk volume on either side of the interface for compounds with small to moderate solid-water distribution ratios (Ki <10 m3kg ) is approximatively given by (see Box 19.1, Eq. 4) ... 

In box models the concentration variables have to be related to the same reference volume. We use total (bulk) volume (indicated by m3, without index). Thus, the dissolved and sorbed (particulate) concentrations per total volume, Cd and Cp are... 

Filter Particulate Analysis. In the laboratory, the filters were immediately placed in a desiccator for 24 hrs and then weighed. The particulate concentration was calculated from this weight and the previously determined tare weight of the filter. The filters were analyzed for mercury by a procedure previously reported by the author (11) consisting of boiling the filters in concentrated nitric acid. After being cooled, aliquots of these solutions were pipetted into the interchangeable sample tubes and analyzed by the direct aeration technique. 

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