Sodium chloride, aerosol particles

Weis DD, Ewing GE (1999) Water content and morphology of sodium chloride aerosol particles. J Geophys Res 104 21275-21285... 

Cle, S. L. Interactive comment on Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC) CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiments by D. Rose et al., Atmos. Chem. Phys. Discuss., 7, S4180-S4183, 2007. 

Sinha, M. P., and S. K. Friedlander, Mass Distribution of Chemical Species in a Polydisperse Aerosol Measurement of Sodium Chloride in Particles by Mass Spectrometry, J. Colloid Inteface Set., 112, 573-582 (1986). 

Mathai CV (1990) Visibility and fine particles. 4. A summary of the A WMA EPA International Specialty Conference. J Air Waste Manage Assoc 40 1486-1494 Matteson MJ, Preiming O, Fox JF (1972) Density distribution of sodium-chloride aerosols formed by condensation. Nature-Phys Sci 238 61... 

Type 5 CPC is meant for protection from air-borne solid particles such as asbestos, lead dust, and other hazardous dusts. For the leak tightness of the suit there are two criteria. The second is total inward leakage (TIL), that is, the overall mean penetration through the suit while worn by test persons in a sodium chloride aerosol atmosphere. The TIL can be used as a laboratory-based efficacy measure for the CPC. It is required from the type 5 CPC that the TIL has to be less than 15v% for 8 test persons out of 10 [EN ISO 13982-1]. That should be severely considered while selecting the type 5 against hazardous chemicals. 

Some of the reports are as follows. Mizukoshi et al. [31] reported ultrasound assisted reduction processes of Pt(IV) ions in the presence of anionic, cationic and non-ionic surfactant. They found that radicals formed from the reaction of the surfactants with primary radicals sonolysis of water and direct thermal decomposition of surfactants during collapsing of cavities contribute to reduction of metal ions. Fujimoto et al. [32] reported metal and alloy nanoparticles of Au, Pd and ft, and Mn02 prepared by reduction method in presence of surfactant and sonication environment. They found that surfactant shows stabilization of metal particles and has impact on narrow particle size distribution during sonication process. Abbas et al. [33] carried out the effects of different operational parameters in sodium chloride sonocrystallisation, namely temperature, ultrasonic power and concentration sodium. They found that the sonocrystallization is effective method for preparation of small NaCl crystals for pharmaceutical aerosol preparation. The crystal growth then occurs in supersaturated solution. Mersmann et al. (2001) [21] and Guo et al. [34] reported that the relative supersaturation in reactive crystallization is decisive for the crystal size and depends on the following factors. 

Atmospheric aerosols are hygroscopic, taking up and releasing water as the RH changes (see also Section C.l) because some of the chemical components are themselves deliquescent in pure form. For example, sodium chloride, the major component of sea salt, deliquesces at 298 K at an RH of 75%, whereas ammonium sulfate, (NH4)2S04, and ammonium nitrate, NH4N03, deliquesce at 80 and 62% RH, respectively. (See Table 9.16 for the deliquescence points of some common constituents of atmospheric particles.) De-... 

The conditions under which HC1 formed in acidified sodium chloride droplets would be expected to enter the gas phase have been treated by Clegg and Brimble-combe (1990). Cadle and co-workers (Robbins et al., 1959 Cadle and Robbins, 1960) observed that NaCl aerosols in the presence of 0.1-100 ppm NOz at relative humidities of 50-100% lost chloride ion from the particles. They ascribed this to the formation of nitric acid from NOz, followed by reaction (1). Schroeder and Urone (1974) subsequently suggested that NOz could react directly with NaCl to produce gaseous nitrosyl chloride, C1NO, which they observed using infrared spectroscopy stoichiometrically, this is represented as... 

Before assessing how a chemical moves in the environment, the relevant media, or compartments, must be defined. The environment can be considered to be composed of four broad compartments—air, water, soil, and biota (including plants and animals)—as shown in Fig. 6.6. Various approaches to modeling the environment have been described.14-16 The primary difference in these approaches is the level of spatial and component detail included in each of the compartments. For example, the most simplistic model considers air as a lumped compartment. A more advanced model considers air as composed of air and aerosols, composed of species such as sodium chloride, nitric and sulfuric acids, soil, and particles released anthropogenically.17 A yet more complex model considers air as composed of air in stratified layers, with different temperatures and accessibility to the earth s surface, and aerosols segmented into different size classes.16 As the model complexity increases, its resolution and the data demands also increase. Andren et al.16 report that the simplest of models with lumped air, water, and soil compartments is suitable for... 

Fig. 2 Relationship between dispersibility (expressed as percent weight of particles less than 7 pm in the aerosol) and crystallinity (by X-ray powder diffraction) of rhDNase powders with different sodium chloride contents. (Adapted from Ref. l)...

The primary requirement is a source of vapor and a less volatile material that serves for condensation nuclei. Sodium chloride is commonly used to produce nuclei in the 10-nm-size range. This can be accomplished by heating the bulk material or by atomizing a dilute solution and drying the aerosol. The nuclei source can be a component (impurity) of the bulk material used, such as in the Rapaport-Weinstock generator, in which the impurity in the nebulized liquid serves as the condensation nuclei [9], The use of heterogeneous nucleation for the formation of particles leads to a substantially more controllable and monodisperse aerosol than without the use of nuclei, that is, homogeneous nucleation. 

Table 8-6 presents an overview on the concentrations of the major ions in rainwater observed at various locations. Table 8-7 provides some information on cloud and fog waters. In maritime regions seasalt is an important source of cloud condensation nuclei, and it undergoes effective below-cloud scavenging as well. Sodium chloride accordingly contributes the largest fraction of all ions in rainwater. Some of the other ions usually are somewhat enriched in comparison with their relative abundances in seasalt. The enrichment of potassium and calcium is due to the admixture of aerosol from continental sources, and that of sulfate arises from the oxidation of gaseous precursors such as dimethyl sulfide of S02- This excess sulfate is associated almost exclusively with submicrometer-sized particles (see Section 7.5.1). 

The hygroscopic growth of pharmaceutical particles is usually less than that of sodium chloride particles. It is, however, not negligible, although it is often neglected in aerosol therapy. This was shown for a number of pharmaceutical aerosols. Particles were produced by nebulization of aqueous solutions of drugs, exposed to dry air and passed through a differential mobility analyzer for selec-... 

Figure 17 Hygroscopic growth of 0.7-pm sodium chloride particles in the respiratory tract of two volunteers as a function of the volnmetric depth to which the particles are carried with the tidal air as aerosol boluses. The sizes of the grown particles were determined with the respiratory aerosol probe (Fig. 4) in the expired air.

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