Aerosol sulfur mass distributions

It was found that the requirements were satisfied for application of the linear regression technique to species mass concentrations in a multicomponent aerosol. The results of 254 particle size distributions measured at China Lake in 1979 indicate that the normalized fine aerosol volume distribution remained approximately constant. The agreement between the calculated and measrued fine particle scattering coefficients was excellent. The measured aerosol sulfur mass distribution usually followed the total distribution for particles less than 1 ym. It was assumed that organic aerosol also followed the total submicron distribution. 

Sulfur mass distribution - The aerosol sampled by the LPI for sulfur analysis was impacted on vaseline-coated stainless steel strips backed by 25 mm glass discs. The sulfur mass deposited on each stage was determined by the technique of flash volatilization and flame photometric detection (FVFPD)(15). 

On the average, the requirements for application of the statistical technique to filter data were met. Analysis of the 254 measured particle size distributions in 1979 indicates that the fine aerosol volume distribution preserved its shape. The measured sulfur mass distribution followed that of the total submicron volume. By difference, it was assumed that the organics did the same. The low relative humidity at China Lake minimized the formation of aqueous solutions due to water condensation on the particles. Therefore, it is expected that the statistical technique can be used with some success with the China Lake filter data. 

Aerosol was occasionally sampled with low pressure impactors (LPI s) to obtain sulfur and elemental mass distributions using the techniques described by Ouimette (13). 

Figure 7. Sulfur size distributions at Grand Canyon National Parky August 1984, The finest aerosols are at the top (stage 8, around 0.1 xm), and the coarsest (8.5 to about 15 xm) are at the bottom. Most sulfur mass occurs between 0.34 and 0.56 xm (stage 6). The periods of August 14 are used for Table 111. (Reproduced with permission from reference 15. Copyright 1988.)...

Cziczo DJ, Thomson DS, Murphy DM (2001) Ablation, flux, and atmospheric implications of meteors inferred from stratospheric aerosol. Science 291 1772-1775 Dachs J, Eisemeich SJ (2000) Adsorption onto aerosol soot carbon dominates gas-particle partitioning of polycyclic aromatic hydrocarbons. Environ Sci Technol 34 3690-3697 Dalleska NF, Colussi AJ, Hyldahl AM, Hoffmaim MR (2000) Rates and mechanism of carbonyl sulfide oxidation by peroxides in concentrated sulfuric acid. J Phys Chem A 104 10794-10796 D Almeida GA, Schitz L (1983) Number, mass, and volume distributions of mineral aerosol and soils of the Sahara. J Clim Appl Meteorol 22 233-243... 

Several methods were used to characterize aerosol distributions within the exposure chambers. The principal method employed a rectangular jet impactor which was inserted through a port in the chamber and used to inertially classify particles larger than 0.3 urn in diameter. As an additional index, total sulfuric acid mass use per total mass flow was calculated to give an approximation of H SO, mass per volume. Since a substantial part of the aerosol distribution in this system was below inertial impaction limits, an electrical mobility size analyzer (Thermo-... 

Fig.2.3. Moments of particle size distribution for nucleation and growth of sulfuric acid aerosol from sulfuric acid vapor at low humidity. Number concentration, cm , x 2E5, 0 mass concentration, g/ccxlE-13, + surface, cm xlE-7, 1/Number, cm ...

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