Sodium chloride, atmospheric aerosol

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-... 

Toon, O. B., J. B. Pollack, and B. N. Khare, 1976. The optical constants of several atmospheric aerosol species ammonium sulfate, aluminum oxide and sodium chloride, J. Geophys. Res.. 81, 5733-5748. 

The emission of sea salt is mainly dependent on wind speed. It is considered the second largest contributor in the global aerosol budget, as a vast area of the earth consists of sea. The aerosols consist mainly of sodium chloride. Other constituents of atmospheric sea salt reflect the composition of sea water (magnesium, sulphate, calcium and potassium). Sea salt is the only pure natural aerosol component. 

Fig. 2. Surface heterogeneity of a powder sample of sodium chloride computed from the adsorption of argon at 76.1 K using a two-dimensional gas model of adsorption, x, Sample prepared by electrostatic precipitation of a NaCl aerosol O, same sample but after annealing at 31(1 315°C in a dry nitrogen atmosphere at 600mmHg. (Reproduced from ref. 4 by courtesty of Academic Press, Inc.)...

Atmospheric aerosols at high relative humidities are aqueous solutions of species such as ammonium, nitrate, sulfate, chloride, and sodium. Cloud droplets, rain, and so on are also aqueous solutions of a variety of chemical compounds. 

Chen, Y-Y and W.-M. G. Lee (2001) The effect of surfactants on the deliquescence of sodium chloride. Journal of Environmental Science and Health, Part A 36, 229-242 Chin, M. (1992) Atmospheric studies of carbonyl sulfide and carbon disulfide and their relationship to stratospheric background sulfur aerosol. Doctoral Thesis, Georgia Institute of Technology... 

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. 

The major ions have two main escape routes from the ocean (1) incorporation into sediments or pore water and (2) ejection into the atmosphere as seasalt spray. This spray is caused by bursting bubbles that produce small particles, called aerosols, that range in diameter from 0.1 to 1000 pm. The annual production rate of seasalt aerosols is large, on the order of 5 x lO kg/y, but virtually all of it is quickly returned when the spray fells back onto the sea surfece. A small fraction (about 1%) is deposited on the coastal portions of land masses and carried back into the ocean by river runoff. As shown in Table 21.6, seasalts represent a significant fraction of dissolved solids in river runoff, especially for sodium and chloride. Due to the short timescale of this process, seasalt aerosol losses and inputs are considered by geochemists to be a short circuit in the crustal-ocean-atmosphere fectory. The solutes transported by this process are collectively referred to as the cyclic salts. ... 

Lacustrine Pertaining to development in lakes Mesic This term has a very broad meaning. In ecology, it refers to moderate conditions with respect to both temperature and moisture. In soil, specifically in soil taxonomy, mesic is used to represent a soil temperature (mean annual) that falls in the range 8-15° C Mole fraction The ratio of the moles of a substance to the total number of moles in the sample. In the atmosphere this is the same as the volume fraction Non-seasalt (nss) The amount of an element or compound in the bulk aerosol mass that is in excess of its seawater ratio with sodium or chloride. Often applied to sulfate Obligatory anaerobes Organisms restricted to life in anaerobic environments... 

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