Atmospheric aerosol contents

The analysis of perturbations to the middle atmosphere must also include natural processes, such as the effects of volcanic eruptions, which produce large quantities of fine particles as well as water vapor and SO2, which eventually produces H2SO4 and sulfate aerosols. The amount of gas injected, the composition and the maximum altitude of injection vary with the intensity of the eruption. Such events can alter the budgets of some atmospheric constituents and are clearly reflected in the middle atmospheric aerosol content. Particles also provide sites for surface reactions to occur. Such heterogeneous reactions may activate chlorine and enhance the depletion of ozone by industrially manufactured halocarbons. 

The existing variety of means and methods of micro-element analysis is used worldwide for the determination of element contents in atmospheric aerosols when they ai e collected at aspiration filters, sediment and natural surfaces and biota objects where toxic substances migration can be observed. 

Pierce, R. C., and M. Katz. Dependency of polynuclear aromatic hydrocarbon content on size distribution of atmospheric aerosols. Environ. Sci. Technol. 9 347-353,... 

On-line measurements of the sulfur content of atmospheric aerosols have been made by removing gaseous sulfur species from the aerosol and then analyzing the particles for sulfur with a flame photometric detector (24) or by using an electrostatic precipitator to chop the aerosol particles from the gas so that the sulfur content could be measured by the difference in flame photometric detector response with and without particles present. These and similar methods could be extended to the analysis of size-classified samples to provide on-line size-resolved aerosol composition data, although the analytical methods would have to be extremely sensitive to achieve the size resolution possible in size distribution analysis. 

Measuring the Strong Acid Content of Atmospheric Aerosol Particles... 

Descriptions of analytical methods for strong acid and acidic sulfate content of atmospheric aerosols have been reviewed (6-10). Methods for acidic aerosol determination are reviewed in this chapter according to the measurement principle either filter collection and post-collection extraction, deriv-atization or thermal treatment, and analysis or in situ collection (real-time or stepwise) and analysis. 

Surface Interactions. Loss of strong acid content of atmospheric aerosols was observed and attributed to reaction with basic sites in the glass or cellulose filter matrices commonly used for high-volume sampling of atmospheric aerosols (46, 50). These filter materials, and glass fiber filters of... 

Nowadays, thermo-optical methods are considered the most reliable measurement techniques for OC/EC split in atmospheric aerosols. Nevertheless, methods for TC/EC/BC analysis in atmospheric particles are still open to debate and their different analytical approaches have been the main cause for performing intercomparison studies (Schmid et al., 2001 ten Brink et al., 2004). The TC measurements showed good agreement, whereas the results of EC/BC determinations were highly variable due to EC overestimation by thermal methods. Furthermore, caution must be taken when using BC as an estimative of the EC content in aerosols, and vice versa BC and EC measurements are associated to the carbon content of colored and refractory organic compounds, respectively, which can lead to substantially different results between methods (Poschl, 2005). 

The observational program included getting information about the content and properties of atmospheric aerosol and most substantial optically active MGCs (03, CO, NOx, S02, etc.), but concentrated on aerosol studies to retrieve data on direct and indirect aerosol RF (ARF). The most interesting (and in many respects unexpected) results were connected with detection of a thick aerosol layer in the troposphere (an important feature of aerosol chemical composition consisted in the presence of a considerable black carbon component) and distinct manifestations of the long-range transport of both aerosol and MGCs. 

The first indirect climatic effect of aerosol (the Twomey effect) is based on the assumption that with a constant equivalent liquid water content (LWC) of clouds an increase in atmospheric aerosol number density (and, hence, concentration of CCN)... 

Since the World Ocean is the most inertial component of the global climate system, analyzing its variability is a top priority, especially as Levitus et al. (2001) detected annual increases in the heat content of the upper layer of all oceans over the last 45 years. With this in mind, Barnett et al. (2001) compared numerical modeling results of the heat content of the upper 3 km layer of various oceans with observational data. Calculations were made using the parallel climate model (PCM) for the atmosphere-ocean system without any flux adjustment. Calculations were made of five versions of the forecast growth in GHG concentration and sulfate aerosol content in the atmosphere. 

Yang, Z.J., Ni, Y.W., Zhang, Q., Chen, J.P., Liang, X.M., 2004. Research on PCDD/Fs contents in several atmospheric aerosol and soil samples collected at Shanghai and Dalian. Guangzhou Environ. Sci. (Chinese) 19, 25-27. 

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