Atmospheric particles cluster

Cluster Analysis of Chemical Compositions of Individual Atmospheric Particles Data... 

K-means cluster analysis is an excellent method for the reduction of individual-partide datai if extra clusters are used to allow for the non-spherical shape and natural variability of atmospheric particles. The "merge" method for choosing seedpoints is useful for detecting the types of lew abundance particles that are interesting for urban atmospheric studies. Application to the Phoenix aerosol suggests that the ability to discriminate between various types of crustal particles may yield valuable information in addition to that derived from particle types more commonly associated with anthropogenic activity. 

The atmosphere, whether in remote or urban areas, always contains significant concentrations of particles, up to 10x cm These may have diameters anywhere within the entire range from molecular clusters to 100 /xm. Because the size of atmospheric particles plays such an important role in both their chemistry and physics in the atmosphere as well as in their effects, it is important to know the distribution of sizes. We thus consider first how these size distributions are characterized. 

Beddows DCS, Dall osto M, Harrison RM (2009) Cluster analysis of rural, urban, and curbside atmospheric particle size data. Environ Sci Technol 43 4694-4700... 

Fig. 10 Comparison between the atmospheric particle- to gas-phase partition coefficients (ftp, in m3/ Jig) for BDE-47, BDE-100, BDE-99, BDE-154, and BDE-153 (clusters from right to left) and their sub-cooled liquid vapor pressures (P [, in Pascals) in the 1997-1999 Chicago air samples (r2 = 0.763, n = 60). From Strandberg et al. [42]...

FIGURE 20.2 Illustration of the size (below particle) and number of molecules (upper right) in atmospheric particles ranging from critical clusters up to cloud drops. The visible spectrum is shown to emphasize the size range (0.1 to 1.0 mm) relevant to aerosol radiative forcing. Nucieation creates new particles that evolve into larger particles relevant to aerosol radiative... 

Kulmala, M., L. Pirjola, and J.M. Makela, Stable sulfate clusters as a source of new atmospheric particles. Nature 404, 66, 2000. 

Some recent examples of the uses for clustering in chemical problems include the following chemical information systems, selection of compounds for biological testing, classification of meteorites, composition of atmospheric particles, characterization of gas chromatographic stationary phases, and studies of IR speara. ... 

T. W. Shatruck, M. S. Getmani, and P. R. Buscek, in Environmental Applications of Che-mometrics. J. J. Breen, Ed., American Chemical Socie, Washington, DC, 1985. Cluster Analysis of Chemical Compositions of Individual Atmospheric Particles Data. 

These quantities depend strongly on the different interaction processes of the decay products in air like attachment to aerosol particles, cluster formation, neutralisation of the cluster, and plateout on surfaces and on composition and behaviour of the atmospheric air (number concentration and size distribution of the aerosol, humidity, trace gases, turbulence). 

Takahama S, Liu S, Russell LM (2010) Coatings and clusters of carboxylic acids in carbon-containing atmospheric particles from spectromicroscopy and their implicatirais for cloud-nucleating and optical properties. J Geophys Res Atmos 115. doi 10.1029 009JD012622... 

Microstructure examinations [61] showed that the enhanced hardening observed with increasing Ni content in RPV steel was accompanied by a reduction in the mean size of Cu-rich clusters and an increase in cluster density. Cu-rich atmospheres and clusters induced by irradiation exhibit signiflcant Ni enrichment. The results [69] of calculations of the Ni and Mn concentrations in the Cu-rich phases suggested that the combined concentration of Mn and Ni in the Cu-rich phases in irradiated RPV steels was 30% or more. A study [69] of FeCuNi alloys showed that an irradiated ternary alloy contained Cu,Ni-rich clusters. The Ni/Cu ratio was 1 3, as compared to 1 50 for the particles found before irradiation. Nickel was also found to be associated with P-rich clusters. 

Interest in the interaction of water and nitric acid has arisen from several considerations involving such widely diverse problems as determining nitric acid uptake by water droplets and ice particles, to questions concerning the co-condensation of water and nitric acid to form polar stratospheric clouds146 and related ones about nitric acid incorporation in protonated water clusters existing in the upper atmosphere. Crutzen and Arnold suggested147 that,... 

Both polonium nuclides are alpha emitters and therefore of particular concern. In health physics it is customary to differentiate between attached and unattached 218Po the former, usually the larger of the two consists of 218Po atoms attached to airborne particles which are copiously present in virtually every atmosphere the latter consists of a 218Po atom or ion, frequently surrounded by several dozen molecules of a condensible species present in the air. The purpose of this paper is to present a new method for measuring the size properties of these unattached 218Po clusters. 

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