Particulate matter determination

E. A. Wolfe, Gas Flow Rate and Particulate Matter Determination of Gaseous Effluents, Bay Area Air Pollution Control District 1480, San Erancisco, Calif., 1961. 

In the evaluation of the toxic characteristics of a gas, volatile chemical, aerosol, or particulate matter, determination of subchronic inhalation toxicity may be performed after initial toxicity information has been obtained via acute testing. It provides information on health hazards likely to arise from repeated exposure by the inhalation route over a limited period of time. Hazards of inhaled chemicals are influenced by the inherent toxicity and by physical factors such as volatility and particle size. The housing and feeding conditions, before and after exposure to environmental chemicals, should be planned according to the standard animal husbandry conditions described for acute oral toxicity study. 

F. Alt, A. Bambauer, K. Hoppstock, B. Mergler, G. Tolg, Platinum traces in airborne particulate matter. Determination of whole content, particle size distribution and soluble platinum, Fresenius J. Anal. Chem., 346 (1993), 693D696. 

The material structure of the particulate matter determines its complex index of refraction, which is considered to be the most fundamental property. The real part of the complex refractive index is the ratio of the speed of light in vacuum to that within the particle for light at normal incidence. In this case, the imaginary part, which is also termed the attenuation, extinction, or absorption index, is directly related to the rate of attenuation of radiation with depth within the material. For other than normal incidence, the relations between the complex index of refraction, speed of light, and attenuation within the particle are complicated and require rigorous solution of the electromagnetic (EM) wave equations (i.e., Maxwell s equations) within the medium of interest with appropriate boundary conditions. 

Boom FA, van der Veen J, Verbrugge P, Van der Vaart FJ, Paalman AC A, Vos TH (2000) Particulate matter determination in LVP s produced in Dutch hospital pharmacies. Part 2 overview of the results. J Pharm Sci Technol 54 343-358... 

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. 

U. S. EPA Regulations on Standards ofPeformanceforNeir Stationay Sources, 40 CER 60, Appendix A, Reference Methods, Washington, D.C., 1993. ASTM D3685-92, Standard Test Methodfor Sampling and Determination of Particulate Matter in Stack Gases, American Society for Testing Materials, Philadelphia, Pa., 1992. 

Receptor Models. Receptor models, by their formulation, are effective in determining the contributions of various sources to particulate matter concentrations. In classic studies, sources contributing to airborne particle loadings have been identified in Washington, D.C. (78), St. Louis (9,24), Los Angeles (7,12), Portiand, Oregon (78), and Boston (79—81), as well as other areas including the desert (82). 

Direct Mass Measurement One type of densitometer measures the natural vibration frequency and relates the amplitude to changes in density. The density sensor is a U-shaped tube held stationaiy at its node points and allowed to vibrate at its natural frequency. At the curved end of the U is an electrochemical device that periodically strikes the tube. At the other end of the U, the fluid is continuously passed through the tube. Between strikes, the tube vibrates at its natural frequency. The frequency changes directly in proportion to changes in density. A pickup device at the cui ved end of the U measures the frequency and electronically determines the fluid density. This technique is usefiil because it is not affec ted by the optical properties of the fluid. However, particulate matter in the process fluid can affect the accuracy. 

The instrumental analyzer procedure, EPA Method 3A, is commonly used for the determination of oxygen and carbon dioxide concentrations in emissions from stationary sources. An integrated continuous gas sample is extracted from the test location and a portion of the sample is conveyed to one or more instrumental analyzers for determination of O9 and CO9 gas concentrations (see Fig. 25-30). The sample gas is conditioned prior to introduction to the gas analyzer by removing particulate matter and moisture. Sampling is conducted at a constant rate for the entire test run. Performance specifications and test procedures are provided in the method to ensure reliable data. 

As the gas stream proceeds through the sampling apparatus, the particulate matter is trapped on a filter, the moisture is removed, and the volume of the sample is measured. Upon completion of samphng, the collec ted material is recovered and sent to a laboratory for a gravimetric determination or analysis. 

In your location, determine whether sulfur dioxide, ozone, or particulate matter contributes to soiling or corrosion problems. 

Pretreatment of the collected particulate matter may be required for chemical analysis. Pretreatment generally involves extraction of the particulate matter into a liquid. The solution may be further treated to transform the material into a form suitable for analysis. Trace metals may be determined by atomic absorption spectroscopy (AA), emission spectroscopy, polarogra-phy, and anodic stripping voltammetry. Analysis of anions is possible by colorimetric techniques and ion chromatography. Sulfate (S04 ), sulfite (SO-, ), nitrate (NO3 ), chloride Cl ), and fluoride (F ) may be determined by ion chromatography (15). 

Pollutant concentration maps may be constructed as shown in Fig. 15-5 (14). In this example, elevated levels of ambient particulate matter are associated with population centers. For a given geographic area, isopleths, lines showing equal concentrations of a pollutant, are drawn on a map. Regions of high concentration are quickly identified. Further action may be taken to determine the cause, such as review of emission inventories of additional sampling. 

For sources having a large component of emissions from low-level sources, the simple Gifford-Hanna model given previously as Eq. (20-19), X = Cqju, works well, especially for long-term concentrations, such as annual ones. Using the derived coefficients of 225 for particulate matter and 50 for SO2, an analysis of residuals (measured minus estimated) of the dependent data sets (those used to determine the values of the coefficient C) of 29 cities for particulate matter and 20 cities for SOj and an independent data set of 15 cities for particulate matter is summarized in Table 20-1. For the dependent data sets, overestimates result. The standard deviations of the residuals and the mean absolute errors are about equal for particulates and sulfur dioxide. For the independent data set the mean residual shows... 

Air sedimentation A measuring technique for particulate matter using a microme-orograph, to determine the Stokes num ber of fall. 

The primary measure of baghouse-system performance is its ability to consistently remove dust and other particulate matter from the dirty-air stream. Pressure drop and collection efficiency determine the effectiveness of these systems. 

If a liquid contairring particulate matter, blood cells, bacteria or srrspensions of inarrimate matter is passed down the tube, when a particle passes through the orifice a change in resistance in the circuit occurs and the change m be recorded by the usual detection or print-out devices. Both the number of particles per unit of time and then-size m be determined. 

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