Aerosol atmospheric/general/transport

The term nebulizer is used generally as a description for any spraying device, such as the hair spray mentioned above. It is normally applied to any means of forming an aerosol spray in which a volume of liquid is broken into a mist of vapor and small droplets and possibly even solid matter. There is a variety of nebulizer designs for transporting a solution of analyte in droplet form to a plasma torch in ICP/MS and to the inlet/ionization sources used in electrospray and mass spectrometry (ES/MS) and atmospheric-pressure chemical ionization and mass spectrometry (APCI/MS). 

A thorough analysis of atmospheric transport and deposition to the Great Lakes has been carried out using the HYSPLIT model developed by the US National Atmospheric and Oceanic Administration (NOAA) [28,29]. An emissions inventory of PCDD/Fs for North America in 1996 was used as input to the model. Factors considered in the fate and distribution were meteorological data, vapor-particle partitioning, aerosol characteristics, reaction with hydroxyl radicals, photolysis, and dry and wet deposition. The model was generally satisfactory at estimating fluxes, except for HpCDD and OCDD, which appeared to be underestimated by about a factor of four. The model output was summarized as 2378-TeCDD toxic equivalent concentrations (TEQs) based on the WHO mammalian 2378-TeCDD toxic equivalent factors (TEFs) [30]. Since HpCDD and OCDD were estimated to contribute only 2% of TEQs, the model was considered to be valid for the purpose intended. 

Figure 2. General scheme of the pathways to the different environmental compartments of chemical elements contained in rocks (not to scale). (1) Weathering, (2) mechanical transport (creep and erosion), (3) transport in the water phase, (4) accumulation in plants and (5) diffuse atmospheric input (aerosols, rain).

Finally, we may point out that there is a possibility that even a nuclear war according to Scenario I, in which most NOx is deposited in the troposphere, may cause ozone depletions in the stratosphere, if the hot fires in the oil and gas production regions become so powerful that the fire plumes penetrate into the stratosphere. Another means of upward transport may occur when the heavy, dark aerosol layer, initially located in the troposphere, is heated by solar radiation and starts to set up convection and wind systems which will transport an appreciable fraction of the fire effiuents into the stratosphere. These speculative thoughts may be pursued further with currentiy available general circulation models of the atmosphere. 

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