Aerosol associations

Natural Visibility Conditions visibility conditions attributable to Rayleigh scattering and aerosol associated with natural processes. 

Based on 46 measurements, the activity median aerodynamic diameter of Pb-212 averaged 0.13 pm (0g = 2.97), while Pb-214 averaged 0.16 pm (Og = 2.86). The larger median size of Pb-214 was attributed to a-recoil depletion of smaller aerosols following decay of aerosol-associated Po-218. 

The aerodynamic size distributions of Pb-214, Pb-212, Pb-210, Be-7, P-32, S-35-SoJ , and stable SO4 were measured using cascade impactors. Pb-212 and Pb-214, measured by alpha spectroscopy, were largely associated with aerosols small than 0.52 11m. Based on over 46 low-pressure impactor measurements, the mean activity median aerodynamic diameter (AMAD) of Pb-212 was found to be 0.13 11m, while for Pb-214 the AMAD was larger—0.16 lim. The slightly larger size of Pb-214, confirmed with operationally different impactors, was attributed to a-recoil-driven redistribution of Pb-214 following decay of aerosol-associated Po-218. A recoil model was presented that explained this redistribution. Low-pressure impactor measurements indicated that the mass median aerodynamic diameter of SoJ ... 

D. Nganga, A. Minga, B. Cros, C. F. Butler, M. A. Fenn, C. S. Long, and L. L. Stowe, Aerosol-Associated Changes in Tropical Stratospheric Ozone Following the Eruption of Mount Pinatubo, J. Geophys. Res., 99, 8197-8211 (1994). 

Simulation of the Dynamical Response of the Arctic Vortex to Aerosol-Associated Chemical Perturbations in the Lower Stratosphere, Geophys. Res. Lett., 23, 1525-1528 (1996). 

Since surfactants are ingredients of pesticide formulations, it appears likely that, after they are sprayed, aerosol-associated surfactant molecules occur in the atmosphere. However, to the best of our knowledge, no accounts of atmospheric occurrence of surfactants exist in the literature. 

McCormick M.P., Trepte C.R. and Kent G.S., Spotted changes in the stratospheric aerosol associated with the North polar vortex. Get hys. Res. Lett. , 10, 941-944 (1983). 

With this vision in mind, Sheldon was one of the original founders of the American Association for Aerosol Research (AAAR). From its humble beginning as a small group in Santa Monica in 1982, the Association has grown to nearly 1000 members. Along with the European Aerosol Association, the AAAR has become a flagship of a network of aerosol associations worldwide. Sheldon served as President of AAAR during 1984-1986, and remained active in the association nntil the time of his death. 

As a result of his contributions and leadership in aerosol science, Sheldon received many honors throughout his career. For example, he received five awards from the American Institute of Chemical Engineers the Colburn Award in 1959, the Alpha Chi Sigma Award in 1974, the Walker Award in 1979, the Cecil Award in 1995, and the Lifetime Achievement Award of the AIChE Particle Technology Forum in 2001. He also received the Humboldt Senior Scientist Award from the West German Government in 1984-1985. He presented several invited lectures around the world, and more recently he was the first recipient of the Christian Junge Award of the European Aerosol Association in 2000 and the Aurel Stodola Medal of ETH in Zurich in 2004. 

The Aerosol Association of Hungary is a part of the European Aerosol Federation. 

Air Chemistry Group in the Hungarian Academy of Science, University Vezsprem Aerosol Association of Hungary... 

As in the case of mercury, a long-term trend in increasing lead concentration is apparent from an examination of lead aerosols associated with Greenland snow10. ... 

As aerosols in the atmosphere originate from multiple sources, the composition of nutrients changes considerably over the four seasons. Nitrate, NOJ, and NHJ are defined as secondary aerosol-associated species and are not associated with primary aerosols. The combustion of fossil fuels is a significant source of NO, whereas NHj may originate from anthropogenic emissions such as animal waste and the application of chemical fertilizers. 

Polymers can be molded in color, which can eliminate the need for painted parts. Eliminating paint is particularly desirable as it reduces air emissions of volatiles and aerosols associated with painting. Eliminating paint also makes the parts easier to recycle. Also, molding plastics require less energy... 

Radioactive aerosols can be classified in the following categories (a) Radioactive aerosols associated with radioactive nuclides of cosmogenic origin, such as Be, Na, and (b) radon and thoron decay product aerosols associated with Po Pb, Pb, Pb, and °Po, (c) fission product radionuclide aerosols associated with Sr, Sr, Cs, Ru, isif 132-pg i40g (-(j) radioactive aerosols associated with the operation of high-energy ac-... 

Radioactive aerosols associated with the cosmic-ray produced radionuclides... 

The aerodynamic size distributions of Pb and SO were quite different, reflecting the different dependencies of surface area and volume on aerosol diameter (Friedlander, 1977). Lead-212, like the other radionuclides, becomes associated with atmospheric aerosol particles by condensation or coagulation processes which are surface-area related. Sulfate, on the other hand, is the main solute in the accumulation mode aerosol so that its steady-state distribution is proportional to volume, even though condensation of H2SO4 may dominate its initial aerosol association. The difference also reflects residence times of 16.7 h for Pb -i- Bi and of about a week for sulfate. 

Papastefanou and Bondietti (1991a, 1991b) performed experiments on the diffusive deposition of aerosol particles on wire screens and, in particular, used Pb deposition as a measure of the collection efficiency of the screens for aerosol-associated attached radionuclides in outdoor air, at Oak Ridge National Laboratory, Oak Ridge, Tennessee (35 58 N, 84 17 W) during the summer period. Stainless steel wire screens (60, 200, as well as 40 and 100 mesh/inch) were used in the experiments to collect the unattached species of radon decay products in ambient aerosols. Glass fibre filters were used as back-up to collect the radon decay products which passed the wire screens. The screens were separated from the back-up filter by a spacer screen (4 mesh/inch) to prevent contamination by the filter deposit (e.g., " Pb atoms) via a-recoil. 

This long held suspicion notwithstanding, definitive (positive) associations of acid aerosol association with adverse human health effects have yet to be demonstrated in any epidemiological... 

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