Volatility atmospheric aerosol

Vented Underground Burst. An underground detonation which produces no visible fireball, but which results in the release of volatile radionuclides through fissures or other vents, produces a single particle class— atmospheric aerosol particles with condensable radionuclides deposited on their surface. Radionuclide abundance is independent of particle size. 

The study described here demonstrates that ESCA provides information regarding the chemical nature of the surface of an unperturbed sample which would be difficult to acquire by other methods. A major weakness of ESCA, the necessity of exposing the sample to vacuum, together with its attendant problem of sample volatilization, can also be one of its strengths. The volatility of some nitrogenous species in atmospheric aerosol particles can be used to provide strong evidence for chemical identity of ionic compounds (e.g., ammonium nitrate) rather than simply ionic identities as provided by wet chemical methods. This volatility is accelerated by x-ray irradiation, so that similar results could be achieved only by extended vacuum exposure alone if another analytical technique were used. Also, with ESCA, volatile losses can be conveniently monitored since the sample remains in the spectrometer throughout the process. 

Thibodeaux, L.J., K.C. Nadler, K.T. Valsaraj, and D.D. Reible. 1991. The effect of moisture on volatile organic chemical gas-to-particle partitioning with atmospheric aerosols — competitive adsorption theory predictions. Atmos. Environ. 25A 1649-1656. 

The concentration of metals in atmospheric aerosols and rainwater (Table 7.1) is therefore a function of their sources. This includes both the occurrence of the metals in combustion processes and their volatility, as well as their occurrence in crustal dust and seawater. As a result of this, the size distribution of different metals is very different and depends on the balance of these sources. For a particular metal this distinction is similar in most global locations (Table 7.2), although some variability does occur as wind speed and distance from source exert an influence on the particle size distribution spectrum (Slinn, 1983). Once in the atmosphere particles can change size and composition to some extent by condensation of water vapour, by coagulation with other particles, by chemical reaction, or by activation (when supersaturated) to become cloud or fog droplets (Andreae et al., 1986 Arimoto et al., 1997 Seinfeld and Pandis, 1998). 

The reactions observed in the photochemical smog, especially those concerning decomposition and oxidation of volatile organic substances, are accelerated by atmospheric aerosols, eg oxidation of some halogenated hydrocarbons, isoprene, monoterpenes, and aromatic hydrocarbons is enhanced by the surfaces of metal oxides, desert sand, volcanic ash, and sea salt [8],... 

Strommen MR, Kamens RM (1999) Simulation of semivolatile organic compound microtransport at different time scales in airborne diesel soot particles. Environ Sci Technol 33 1738-1746 Thibodeaux LJ, Nadler KC, Valsaraj KT, Reible RR (1991) The effect of moisture on volatile organic chemical gas-to-particle partitioning with atmospheric aerosols-competitive adsorption theory predictions. Atmos Environ 25A 1649-1656 Thompson JD, Cramer CJ, Truhlar DG (2003) Predicting aqueous solubilities from aqueous free energies of solvation and experimental or calculated vapor pressures of pure substances. J Chem Phys 19 1661-1670... 

Aerosol mass spectrometry (AMS) is used to monitor the chemical composition of particulate matter in the atmosphere. Commercial AMS instruments can provide size and chemical mass loading data on aerosol particles in real time [176]. Such instruments integrate sampling and MS analysis sub-systems. They can be installed permanently or used as components of mobile laboratories [176]. Both quadrupole and TOF AMS devices can provide quantitative data on the chemical composition of volatile/semi-volatile submicrometer aerosols [177]. Importantly, AMS can provide non-refractory aerosol mass... 

As mentioned before, POP transport in the environment depends on their physicochemical properties [40-54], and these include saturated vapor pressure, solubility, Henry s law constant, octanol-water, octanol-air, and organic carbon-water partition coefficients. The saturated vapor pressure characterizes the capability of a substance to be transferred to the gaseous state. Eollowing the study of Wania and Mackay [40], the efficiency of POP condensation with subcooled liquid pressure (p°L) at 25°C above 1 Pa is very low. POPs with a vapor pressure between 1 and 10" Pa are condensed at a temperature of about -30°C and their deposition may be expected mostly in the polar latitudes. POPs with a vapor pressure of subcooled liquid from 10" to 10" Pa are condensed at a temperature above 0°C and they may reach to the middle latitudes. EinaUy, POPs of low volatility with a vapor pressure of subcooled liquid below 10" Pa are practically not vaporized and these substances may be transported and deposited as fine aerosols or coarse particles [39]. Using the vapor pressure of the subcooled liquid it is possible to characterize the partitioning of a POP between the gas phase and the solid phase of the atmospheric aerosol. The POPs having a lower vapor pressure are better bound with... 

Concentrations of Pb(CH3)4 and other tetraalkyllead compounds in atmospheric samples, which have been measured at different locations with species specific analytical methods, are listed in Table 11. Tetraalkyllead concentrations in indoors air were found to correspond closely with those in outdoors air [24]. More data on concentrations of alkyllead compounds in ambient air have been obtained with analytical methods which measure volatile organolead compounds or total organolead [28 to 55,173]. However, these data, being based on different sampling and analytical procedures, are difficult to compare see also [56 to 64]. According to [5], the results given in [28, 29, 32, 33] are probably unreliable. In this context it has to be considered that the majority of the nonfilterable (molecular) lead seems not to be organic in nature [58, 59] recently also tri- and/or dialkyllead compounds have been determined besides Pb(CH3)4 and other tetraalkyllead compounds in both urban and rural air in the vapor phase and in atmospheric aerosols [27,174] see also [182]. For analytical procedures to determine Pb(CH3)4 in atmospheric samples, see Section 1.1.1.1.1 on p. 75. 

The transport processes involved in the exchange of organic chemicals between the atmosphere, plant canopies, and the soil surface are illustrated in Figure 7.1. Transfer from the atmosphere to the canopy can occur by wet deposition in the form of rain, snow or fog, dry deposition of chemical associated with atmospheric aerosols, or dry deposition of gases. Transfer from the canopy to the atmosphere can occur via suspension of chemical associated with particles or volatilization. Transfer from the canopy to surface soil can occur via sedimentation, whereby again both wet and dry processes contribute. Resuspension of soil particles can result in transfer of chemical to the canopy foliage. Finally, chemicals can volatilize from the canopy to the subcanopy air, whereby some fraction may sorb to the soil (with the remainder being advected either vertically or horizontally out of the canopy), or they may volatilize... 

Pirrone N, Hedgecock 1, Forlano L. 2000. The role of the ambient aerosol in the atmospheric processing of semi-volatile contaminants a parameterised numerical model (CASPAR). J Geophys Res 105(D8) 9773-9790. 

Finizio A, Mackay D, Bidleman T, Hamer T (2007) Octanol-air partition coefficient as a predictor of partitioning of semi-volatile organic chemicals to aerosols. Atmospheric Environment 31 2289-2296... 

Examples of such procedures are making dilutions (not all components of the mixture may be equally soluble or miscible with the vehicle) and generating either vapors or respirable aerosols (not all the components may have equivalent volatility or surface tension, leading to a test atmosphere that contains only a portion of the components of the mixture). 

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