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[en] Suspended particulate matters (SPM) collected hourly at that time of Fukushima Dai-ichi Nuclear Plant accident in 2011 on a filter tape at many automated SPM monitoring stations located widely in eastern Japan was analyzed in order to determine atmospheric radiocesium concentration. Precise time series of 137Cs concentrations in wide areas of eastern Japan were revealed. Analysis of radioactivity of SPM collected on filter tapes by automated SPM monitoring stations even at 1-2 years after the accident is concluded to give very valuable information to resolve the matter of radioactive contamination by Fukushima accident. (author)
[en] We report that ejecta physics is a young field, having developed over the last 60 years or so. Essentially, ejecta forms as a spray of dense particles generated from the free surface of metals subjected to strong shocks, but the detailed mechanisms controlling the properties of this particulate ejecta are only now being fully elucidated. The field is dynamic and rapidly growing, with military and industrial applications, and applications to areas such as fusion research. This Special Issue on Ejecta reports the current state of the art in ejecta physics, describing experimental, theoretical and computational work by research groups around the world. While much remains to be done, the dramatic recent progress in the field, some of it first reported here, means that this volume provides a particularly timely review. In this foreword, we provide a brief historical overview of the development of ejecta physics, to define the context for the work in the rest of this Special Issue.
[en] Response of several particulate monitoring instruments to aerosols which might be encountered during monitoring of an in situ oil spill burn, was examined. The aerosols included road dust, salt and particulates from the combustion of heptane, diesel fuel and crude oil. Total suspended particulates, 10 micron and 2.5 micron sampling heads were used with each instrument. Two optical cell instruments reported similar concentrations as reported by gravimetric instruments in the case of burning heptane, diesel fuel and crude oil. For salt and road dust aerosols, two optical cells reported much lower values than those measured by gravimetric instruments. The differences were attributed to salt and road dust aerosols having different size distributions. These differences, however, can be minimized by careful calibration. Results indicate that with careful calibration any of the instruments tested can be used as a monitoring tool to help response teams to assess whether in situ burning is leading to an increase in airborne particulates above an acceptable level. 8 refs., 7 tabs., 24 figs
[en] A particle collector breadboard testing system (Racetrack), based on the ACE1.0 particle collector model, was designed and built to study the mechanisms for particle collection and detection. Several parameters were investigated, such as current and voltage of the filament, magnetic fields and supporting electronics. Advanced optical spectroscopic features with data logging capabilities were designed in this project. The advanced features were tested for future incorporation into a new breed of particle collectors. Several experiments conducted with the Racetrack provided a path for a new prototype particle collector “ESP-EV1”. Preliminary results suggest that the new particle collector is an order of magnitude more efficient in collecting material than currently used collector systems. This project also demonstrated the capability to extract nanoparticulates from a sample containing material from 100 nm to 10 micron-sized particulates.
[en] A study of air pollution in different sites of five Syrian cities (Damascus, Aleppo, Tartous, Homs, and Sweda) was carried out. The concentrations of total suspended particulate less than 10 microns (PM 10) and less than 3 micron (PM3) were measured using high volume air sampler (HVAS). Heavy element concentration, Pb, Cd, Zn and Cu were also determined using high volume air sampler (HVAS). Heavy element concentrations, Pb, Cd, Zn and Cu were also determined using anodic stripping voltammetry. The result showed that TSP, PM10 and PM3 were higher than WHO standards in several times. Mean lead concentrations ranged between 0.58 and 2.96 μg/m3 and 0.56 and 1.53 μg/m3 in Damascus and Aleppo respectively, while in the other cities these concentrations were less than WHO standards (0.5 - 1 μg/m3). (author)
[en] A comparative analysis was made in this work among Pasquill-Gifford (PG) atmospheric dispersion coefficients and those determined at the Juelich and Karlsruhe sites with the purpose of suggesting which one would be the most applicable to the Angra site. Each one of the three systems was determined by different experiments, carried out over sites with diversified features. The systems of Juelich and Karlsruhe were obtained over sites with high surface roughness and from stacks (elevated releases), while the PG system was obtained over sites with a small surface roughness and from ground level releases. The results of the application of these systems at a complex site like Angra,which has a highly diversified structure encompassing sea, vegetation, predominance of light winds and stable stability classes, show that the PG system, the most used in the world, is still the best choice. (author)
[en] The size characteristics of atmospheric aerosol over the tropical region of Lagos, Southern Nigeria were investigated using two years of continuous spectral aerosol optical depth measurements via the AERONET station for four major bands i.e. blue, green, red and infrared. Lagos lies within the latitude of 6.465°N and longitude of 3.406°E. Few systems of dispersion model was derived upon specified conditions to solve challenges on aerosols size distribution within the Stokes regime. The dispersion model was adopted to derive an aerosol size distribution (ASD) model which is in perfect agreement with existing model. The parametric nature of the formulated ASD model shows the independence of each band to determine the ASD over an area. The turbulence flow of particulates over the area was analyzed using the unified number (Un). A comparative study via the aid of the Davis automatic weather station was carried out on the Reynolds number, Knudsen number and the Unified number. The Reynolds and Unified number were more accurate to describe the atmospheric fields of the location. The aerosols loading trend in January to March (JFM) and August to October (ASO) shows a yearly 15% retention of aerosols in the atmosphere. The effect of the yearly aerosol retention can be seen to partly influence the aerosol loadings between October and February. - Highlights: • Determining the aerosol size distribution via enhanced dispersion model. • Satellite exploration of aerosol optical properties using AERONET. • Comparative simulation between Reynolds and Unified number. • Extensive application of the aerosol optical depth. • Comparative analysis of AOD models. - Determining the aerosol size distribution using an enhanced dispersion model.
[en] The correlation between intensity fluctuations (CIF) of an electromagnetic scattered field generated by a particulate collection was studied. It is demonstrated that the normalized CIF in a scattered field can be decomposed into two mutually independent parts: one is governed by the polarization property of the incident field, called the polarization-induced CIF change; the other is governed by the structural characteristics of the scattering medium, which is called the scattering-induced CIF change. Two special particulate media—i.e. random-distributed particles collection and deterministic-distributed particles collection—were discussed to show the changes of the normalized CIF in the scattered field. (letter)
[en] The impact of aerosol particulate matter of mean mass aerodynamic diameter (le) 2.5 ∝m (PM 2.5 aerosols), on health, visibility, and compliance with EPA's regional haze regulations is a growing concern. Techniques that can help better characterize particulate matter are required to better understand the constituents, causes and sources of PM 2.5 aerosols. Measurement of the 14C/C ratio of the PM 2.5 aerosols, the absence of 14C in fossil carbon materials and the known 14C/C levels in contemporary carbon materials allows use of a two-component model to derive contemporary and fossil carbon contents of the particulate matter. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading. Here, the methodology for performing such an assessment using total suspended particulate Hi-vol aerosol samplers to collect PM 2.5 aerosols on quartz fiber filters and the technique of accelerator mass spectrometry to measure 14C/C ratios is presented and illustrated using PM 2.5 aerosols collected at Yosemite National Park