Of aerosol sources

Then the unattached fraction was calculated in each measurement and was found to be between. 05 and. 15 without aerosol sources in the room and below. 05 in the presence of aerosol sources. The effective dose equivalent was computed with the Jacobi-Eisfeld model and with the James-Birchall model and was more related to the radon concentration than to the equilibrium equivalent radon concentration. On the basis of our analysis a constant conversion factor per unit radon concentration of 5.6 (nSv/h)/(Bq/m ) or 50 (ySv/y)/(Bq/m3) was estimated. 

Our analysis shows that the unattached fraction in the domestic environment is between. 05 and. 15 without any aerosol sources in the room and can decrease below. 05 in the presence of aerosol sources. These values are much larger than assumed by James (1984) (fp-3%) and by the NEA-report (1983) (fp=2%). However the few experimental results reported in the literature agree with our findings. Bruno (1983) found an unattached fraction of. 07 and Reineking (1985), Shimo (1984) and Duggan (1969) measured about. 10. The last two results are calculated by means of the room model from the reported unattached Po-218 concentrations. 

Among these techniques are various forms of a statistical method called factor analysis. Several forms of factor analysis have been applied to the problem of aerosol source resolution. These different forms provide several different frameworks in which to examine aerosol composition data and Interpret it in terms of source contributions. 

Gatz, D. F. Identification of Aerosol Sources in the St. Louis Area Using Factor Analysis, J. Appl. Met., 1978, 1, 600. 

Review of the Chemical Receptor Model of Aerosol Source Apportionment... 

There are two general types of aerosol source apportionment methods dispersion models and receptor models. Receptor models are divided into microscopic methods and chemical methods. Chemical mass balance, principal component factor analysis, target transformation factor analysis, etc. are all based on the same mathematical model and simply represent different approaches to solution of the fundamental receptor model equation. All require conservation of mass, as well as source composition information for qualitative analysis and a mass balance for a quantitative analysis. Each interpretive approach to the receptor model yields unique information useful in establishing the credibility of a study s final results. Source apportionment sutdies using the receptor model should include interpretation of the chemical data set by both multivariate methods. 

The chemical receptor model is one of the most precise tools currently available for assessing the Impact of aerosol sources. 

There is a need today to quantify the effects of aerosol sources on ambient particulate matter loadings. Identifying the major sources of ambient particulate matter loadings was a fairly simple process when values exceeded 500 /ig/m and stack emissions were plainly visible. Control of these emitters was forthcoming and effective. At levels of 150 to 200 fxg/w , the use of annual emission inventories focused further regulatory efforts on major sources which have resulted in more successful reductions. Presently, at levels around 75-100 /ig/m, the uncertainties involved in these assessments of source contributions are greater than the contributions themselves. 

Figure 4.4-5 VANESA calculations of aerosol source rates...

Existing methods for monitoring the transport of gases were inadequate for studying aerosols. To solve the problem, qualitative and quantitative information were needed to determine the sources of pollutants and their net contribution to the total dry deposition at a given location. Eventually the methods developed in this study could be used to evaluate models that estimate the contributions of point sources of pollution to the level of pollution at designated locations. 

Most tanks store Hquid rather than gases or soHds. Characteristics and properties such as corrosiveness, internal pressures of multicomponent solutions, tendency to scale or sublime, and formation of deposits and sludges are vital for the tank designer and the operator of the tank and are discussed herein. Excluded from the discussion are the unique properties and hazards of aerosols (qv), unstable Hquids, and emulsions (qv). A good source of information for Hquid properties for a wide range of compounds is available (2). 

HGSystem offers the most rigorous treatments of HF source-term and dispersion analysis a ailable for a public domain code. It provides modeling capabilities to other chemical species with complex thermodynamic behavior. It treats aerosols and multi-component mixtures, spillage of a liquid non-reactive compound from a pressurized vessel, efficient simulations of time-dependent... 

Interest in the elemental composition of aerosol particles arises from concerns about health effects and the value of these elements to trace the sources of suspended particles. The following physical analysis methods have been applied for the elemental measurements of aerosol samples. A schematic drawing of an x-ray fluorescence system is presented in Fig. 13.42. 

Table V Methods of Identifying Sources of Elements in Aerosols and Surface Dust...

There is a large variety of atmospheric sulfur compounds, in the gas, solid, and liquid phases. Table 7-3 lists a number of gaseous compounds, range of concentration, source, and sink (where known). As this list illustrates, a significant number of these gases contribute to the existence of oxidized sulfur in the forms of SO2 and sulfate aerosol particles. Table 7-4 lists the oxy-acids of sulfur and their ionized forms that could exist in the atmosphere. Of these the sulfates certainly are dominant, with H2SO4 and its products of neutralization with NH3 as the most frequently reported forms. 

The paper summerizes the experimental data on the equilibrium factor, F, the free fraction, fp, the attachment rate to the room air aerosol, X, the recoil factor,, and the plateout rates of the free, qf, and the attached, q3, radon daughters, determined in eight rooms of different houses. In each room several measurements were carried out at different times, with different aerosol sources (cigarette smoke, stove heating etc.) and under low (v<0.3 It1) and moderate (0.3[Pg.288]

The mean value of the equilibrium factor F measured in houses without aerosol sources was 0.3 t 0.1 and increased up to 0.3 by additional aerosol particles in the room air. The fraction of the free radon daughters had values between fp = 0.06-0.13 with a mean value near 0.1. Only additional aerosol sources led to a decrease of f - values below 0.05. 

The rooms without aerosol sources and low ventilation rate (v<0.3 hf1 ) had low aerosol concentrations (2 103 - 104 cm-3) due to the small influence of the higher aerosol concentrations outdoors (aerosols by traffic and combustions) (Table la). In this case the aerosol in the room air was aged by coagulation and plateout and had less condensation nuclei of smaller sizes (d<100 nm). Rooms with a moderate ventilation show higher particle concentrations ((1-5) 10 cm 3) (Table Ila). With aerosol sources in a room (Table III) the aerosol concentrations can increase to 5 105 particles/cm3. The relative error of the measured particle concentration is in the order of 15% primary determined by the uncertainties of the absolute calibrations of the condensation nuclei counter. 

The equilibrium factor F in low ventilated rooms without aerosol sources varied between 0.2 and 0.4 (Table la) with an average value near 0.30 a similar value as reported by Keller and Folkert, 1983, and by Wicke and Porstendorfer, 1982. In rooms with additional aerosol sources an average F-value between 0.4 and 0.5 was obtained (Table III). An error of about 20 % can be estimated for the equilibrium factor. 

The free fraction of the radon daughters f measured in rooms with lo i/ ventilation and no aerosol sources shows values between 0.06 - 0.15 (Table lb) with a mean value near 0.10. In this case the values of the attachment rates X range between 20 hr and 40 hr. The fp-values < 0.05 were obtained in rooms with aerosol sources, which always had values of the attachment rate > 100 It1 (Table III). 

The results of these measurements show that the fraction of the free radon daughters in rooms with low and moderate ventilation and without any aerosol sources are higher (fp = 0.06 - 0.15) than proposed in literature (Jacobi and Eisfeld, 1980 ICRP 32, 1981 NEA, 1983). A mean value of 10 % (fp = 0.1) was determined. Only additional aerosol sources in a room such as cigarette smoke, cooking, candle light or stove heating led to a decrease of the fp-value below 0.05. 

The mean value of the equilibrium factor F in houses i/as 0.3 0.1 without aerosol sources and can increase up to 0.3 with cigarette smoke in the room air. 

As a rule, simulations consider emissions of heavy metals from anthropogenic and natural sources, transport in the atmosphere and deposition to the underlying surface (Figure 6). It is assumed that lead and cadmium are transported in the atmosphere only as a part of aerosol particles. Besides, chemical transformations of these metals do not change removal properties of their particles-carriers. On the contrary, mercury enters the atmosphere in different physical and chemical forms and undergoes numerous transformations during its pathway in the atmosphere (Ilyn et al., 2002 2004 Ilyin and Travnikov, 2003). 

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