Aerosol direct observation

Direct Observation of Aerosols Enhanced by Special Light 1110... 

Jayaraman, A., D. Lubin, S. Ramachandran, V. Ramanathan, E. Woodbridge, W. D. Collins, and K. S. Zalpuri, Direct Observations of Aerosol Radiative Forcing over the Tropical Indian Ocean during the January-February 1996 Pre-INDOEX Cruise, J. Geophys. Res., 103, 13827-13836 (1998). 

The introduction of the electrical aerosol analyzer allowed direct observations of the evolution of the size distribution of the fine aerosol particles (41). The growing aerosol was found to develop what appeared to be an... 

Indirect climate effects of aerosols are more complex and more difficult to assess than direct effects because they depend on a chain of phenomena that connect aerosol levels to concentrations of cloud condensation nuclei, cloud condensation nuclei concentrations to cloud droplet number concentrations (and size), and these, in turn, to cloud albedo and cloud lifetime. Changes in the number concentration of aerosols are observed to cause variations in the population and sizes of cloud droplets, which are expected to cause... 

Finally, for a complete picture of the multiple roles of surface-active organic material in the chemistry and physics of aerosols, field experiments are needed which couple direct observations of aerosol heterogeneous chemistry [148], CCN, and ESf activity with studies of aerosol composition, surface tension, and particle morphology. New techniques which provide speciated ambient aerosol organic composition [297] or functional group information [298] are expected to yield additional insight. 

Bertram TH, Thornton JA, Riedel TP, Middlebrook AM, Bahreini R, Bates TS, Quinn PK, Coffman DJ (2009) Direct observations of N205 reactivity on ambient aerosol particles. Geophys Res Lett 36 L19803. doi 10.1029/2009GL040248... 

Irregular respiration was observed in both male and female rats after a 4-hour nose-only inhalation exposure to aerosolized endosulfan (Hoechst 1983a). In both male and female rats, dyspnea was observed at the lowest concentrations tested (12.3 and 3.6 mg/m for males and females, respectively). Autopsies of the rats that died revealed dark-red, pinhead-sized foci on the lungs. It is unclear whether these effects represent direct effects of inhaled endosulfan on respiratory tissues or whether they are secondary to central nervous system effects on respiratory function. No treatment-related effects were... 

In support of the conclusion based on silver, series of 0.2, 0.5, 1.0, 2.0, and 5.0 % w/w of platinum, iridium, and Pt-Ir bimetallic catalysts were prepared on alumina by the HTAD process. XRD analysis of these materials showed no reflections for the metals or their oxides. These data suggest that compositions of this type may be generally useful for the preparation of metal supported oxidation catalysts where dispersion and dispersion maintenance is important. That the metal component is accessible for catalysis was demonstrated by the observation that they were all facile dehydrogenation catalysts for methylcyclohexane, without hydrogenolysis. It is speculated that the aerosol technique may permit the direct, general synthesis of bimetallic, alloy catalysts not otherwise possible to synthesize. This is due to the fact that the precursors are ideal solutions and the synthesis time is around 3 seconds in the heated zone. 

In a search for sources of alkaline materials in rural air and rain, we have sampled and performed multi-element analyses on ambient particulate matter and potential source materials. Ambient aerosols were sampled daily using single Nuclepore filters or Florida State University "streakers." Samples of soil and unpaved road materials were also collected and analyzed. The samples were analyzed by various multi-element methods, including ion-and proton-induced X-ray emission and X-ray fluorescence, as well as by atomic absorption spectrophotometry. Visual observations, as well as airborne elemental concentration distributions with wind direction and elemental abundances in aerosols and source materials, suggested that soil and road dust both contribute to airborne Ca. Factor analysis was able to identify only a "crustal" source, but a simple mass balance suggested that roads are the major source of Ca in rural central Illinois in summer. 

The conditions under which HC1 formed in acidified sodium chloride droplets would be expected to enter the gas phase have been treated by Clegg and Brimble-combe (1990). Cadle and co-workers (Robbins et al., 1959 Cadle and Robbins, 1960) observed that NaCl aerosols in the presence of 0.1-100 ppm NOz at relative humidities of 50-100% lost chloride ion from the particles. They ascribed this to the formation of nitric acid from NOz, followed by reaction (1). Schroeder and Urone (1974) subsequently suggested that NOz could react directly with NaCl to produce gaseous nitrosyl chloride, C1NO, which they observed using infrared spectroscopy stoichiometrically, this is represented as... 

Gschwend and Hites (1981) observed that the two closely related polycyclic aromatic hydrocarbons, phenanthrene and anthracene, occur in a ratio of about 3-to-l in urban air. In contrast, sedimentary deposits obtained from remote locations (e.g., Adirondack mountain ponds) exhibited phenanthrene-to-anthracene ratios of 15-to-l. You hypothesize that these chemicals are co-carried in aerosol droplets from Midwestern U.S. urban environments via easterly winds to remote locations (like the Adirondacks) where the aerosol particles fall out of the atmosphere and rapidly accumulate in the ponds sediment beds without any further compositional change (i.e., the phenanthrene-to-anthracene ratio stops changing after the aerosols leave the air). If summertime direct photolysis was responsible for the change in phenanthrene-to-anthracene ratio, estimate how long the aerosols would have to have been in the air. Comment on the assumptions that you make. What are your conclusions ... 

As Martell has pointed out (30), in the region of the stratospheric large particle layer near 18-20 km. altitude, radioactive aerosol particles become attached to natural sulfate particles in the size range of about 0.1-0.4 jumeter radius. Subsequent upward transport of the radioactive aerosols is opposed by gravitational sedimentation. This combination of processes affords an explanation for the observed accumulation of 210Pb near 20 km. in the tropical stratosphere (2). At higher latitudes where slow mean motions are directed poleward and downward, no such accumulation is possible. 

PERSONAL MONITORING IS A RELATIVELY NEW CONCEPT in community air pollution measurement research (1-3). This fact is not surprising because most air pollution investigations have been directed toward the characterization of the ambient atmosphere, the observation of pollutant trends, the acquisition of data on chemical kinetic parameters and on the physical properties of aerosols, and the determination of compliance to national and other standards (4). Before the late 1970s, research on personal monitors was primarily conducted in industrial settings (5, 6) because American Confer-... 

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