Aerosol characterization sampling

The aerosol generation/sampling system which was used for this was built and characterized in a previous study (ll). The system was found to produce 90 of the particle mass in the size range of 0.1 to 10 pm. 

What is known for certain is that WSOM components constitute a substantial fraction of OAs. To date, only a small number of aerosol WSOM samples have been studied and characterized, and most of them were collected in European locations. Besides, each collected sample was extracted and isolated by different procedures, which hinders the comparison of the fine physical and chemical properties of the isolated organic fractions. The establishment of a standardized analytical methodology for WSOM extraction and isolation seems to be an important prerequisite for efficient further characterization of aerosol WSOM samples from different areas with different degrees of pollution (urban versus rural versus remote areas in different regions of the world). 

The non-sea spray effects on the levels of Ca, Cl, K, Mg and Na as well as sulfate in snow samples from Terra Nova Bay were ascertained (66). Sampling mode and analytical approach (based on IC) fully complied with criteria previously set up. For Ca and K it was concluded that a nearly uniform background aerosol characterizes the area investigated, which adds to the contribution of marine spray. The oxidation of DMS, in turn, is the dominant source of non-sea spray sulfate. 

O Connor BH and Jaklevic JM (1981) Characterization of ambient aerosol particulate samples from the St. Louis Area by X-ray powder diffractometry. Atmos Environ 15 1681-1690. 

Receptor models are powerful tools for source apportionment of particulates because a vast amount of particulate species characterization data have been collected at many sampling sites worldwide, and because many aerosol species are primary pollutants. Most of the information available is for elemental concentrations, eg, lead, nickel, and alurninum, although more recent measurements have provided data on concentrations of ionic species and carbonaceous compounds. At a sampling (or receptor) site, the aerosol mass concentration of each species i is... 

Kanapilly GM, Stanley JA, Newton GJ, et al. 1983. Characterization of an aerosol sample from the auxiliary building of the Three Mile Island reactor. Health Phys 45(5) 981-989. 

The principle of inertial impaction is employed to sample aerosols aerodynamically for characterization of particle size and will be dealt with theoretically later in this chapter. 

Cluster analysis Is used to determine the particle types that occur in an aerosol. These types are used to classify the particles in samples collected from various locations and sampling periods. The results of the sample classifications, together with meteorological data and bulk analytical data from methods such as instrunental neutron activation analysis (INAA). are used to study emission patterns and to screen samples for further study. The classification results are used in factor analysis to characterize spatial and temporal structure and to aid in source attribution. The classification results are also used in mass balance comparisons between ASEM and bulk chemical analyses. Such comparisons allow the combined use of the detailed characterizations of the individual-particle analyses and the trace-element capability of bulk analytical methods. 

For fine particles, despite the fact that the major rationale behind diffusive sampling of a gas is to achieve discrimination from the concurrently present atmospheric aerosol, relatively little attention has been paid to actually characterizing the particle transmission through these systems. A summary of existing data has been presented (40). The only thorough charac-... 

Al fundamental question about the interpretation of acidic aerosol data is whether researchers can characterize past and current atmospheric concentrations and distributions (spatial and temporal) with sufficient accuracy for studies of their effects on ecosystems and human health. Part of the answer to this question can be provided by a review of the methods that have been used to measure the strong acid content of aerosol particles collected from the atmosphere. This chapter serves as such a review, and, in evaluating analytical procedures, it specifically assesses the ability of each procedure to overcome sampling artifacts, to distinguish between strong and weak acids, to properly partition strong acidity between gas-phase and aero-sol-phase species, and to quantitate strong acidity at the levels at which it is found in the ambient atmosphere. 

Measurements of the air mobility spectrum seem to add considerable information toward an understanding of aerosol formation and growth at sizes below a few nanometers. Hence, to characterize nucleation mechanisms more precisely, such data should be included in experimental designs. Lagrangian aerosol sampling techniques would also be favored, since this approach can yield data on microphysical evolution without the complicating effects of a changing air mass. Further laboratory studies should be undertaken to quantify the thermodynamic data that define ion properties under tropospheric conditions, at ion sizes and compositions relevant to aerosol nucleation. The sparseness of such data imposes a limitation on our ability to quantify ion-based nucleation mechanisms [19,33],... 

Heightened interest on air reactions that can be associated with C cycle and climate changes include NOM compounds. Therefore, there are demands for characterization and reaction mechanisms of NOM in aerosols from different origins, namely, urban, rural, from biomass burning, and others. On that account, spectroscopic techniques, combined with adequate sample preparation methods, could bring additional insights into aerosol research studies. 

After the collection of particles, it is useful to determine the chemical characteristics of the material. This can be accomplished in terms of analysis of a whole sample corresponding to the total mass concentration, or it can be done on a size-fractionated basis. In some cases, individual particles can also be examined. Chemical characterization is very important when one is considering a heterogeneous collection of aerosol particles such as those found in the ambient air or in the workplace. These include whole sample microscopic analysis by collected batch, as well as continuous measurement. 

A dry packed column with porous material was used for the characterization according to size of the PVAc latex samples. The packing employed was CPG (Controlled Pore Glass), 2000 A, 200-400 mesh size. Deionized water with 0.8 gr/lit Aerosol O.T. (dioctyl sodium sulphosuccinate), 0.8 gr/lit sodium nitrate and 0.4 gr/lit sodium azide served as the carrier fluid under a constant flowrate. The sample loop volume was 10 pC A Beckman UV detector operating at 254 nm was connected at the column outlet to monitor particle size. A particle size-mean retention volume calibration curve was constructed from commercially available polystyrene standards. For reasons of comparison, the samples previously characterized by turbidity spectra were also characterized by SEC. A number of injections were repeated to check for the reproducibility of the method. 

As a final test, three different analysts applied the method to the analysis of Cd, Co, Cr, Ni, and Pb on filter samples from the generation system. The results of this test are presented in Table XXI. Small differences (3 percent) were experienced, but the overall percent standard deviation for each metal compares well with the percent standard deviation obtained in the characterization of the aerosol generation system by analyses performed by a single operator. 

Commercial devices do not lead to monodispcrscd particles and often the size distribution is wide and the particles may exhibit varying shapes. Therefore a number of terms are used to adequately characterize an aerosol sample ... 

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