Atmospheric Dust Samples Research Articles

Tungsten-181 and other short lived fission products in ground level air in North Germany and North Norway.

SAMPLES of atmospheric dust have been collected for several years at 1.5 m above ground in Brunswick (52° 18′ N, 10° 28′ E) as part of an environmental radioactivity surveillance programme. Before analysis, each filter, made from ‘Microsorban’ (Delbag, Berlin) is ashed at 450° C. The content of fresh fission products in the samples is then measured in a 10 cm by 10 cm NaI(T1) well-type scintillation spectrometer. Later, the ashes of all filters exposed during half a month—containing dust from about 50,000 m3 of air—are combined and measured in a 45 cm3 well-type Ge(Li) detector with a multichannel analyser (ND 2200). The activity concentrations of various fission products and certain cosmogenic radionuclides are evaluated from the γ-spectra numerically. Since October 1970 a filter sample containing dust collected from about 300,000 m3 of air in Tromso (Norway) is also analysed once a month. Within recent months fresh fission products were detected on three occasions.

Eine neue Interpretation der vertikal integrierten Bewegungsgleichungen

Qualitative infrared microspectrophotometric analysis of 99 six-hour samples of atmospheric dust collected during April and May 1968 at a mountain laboratory in south central New Mexico, U. S. A., revealed a systematic, meteorologically interpretable, temporal variation in the mineral constituency of the dust. The ratio of silicate clays to carbonates was high during the early morning, at times of convective activity and precipitation, and at times of cold frontal passage from the east; it was low during the afternoon and at times of convective inactivity and no precipitation. The low ratio dust is attributed to advection of fresh continental particles from the exchange layer over the adjacent basin and mountains and the high ratio dust to advection of fresh continental particles from the western Great Plains and aged continental particles from the free atmosphere.

Continental dust in the atmosphere of the Eastern Equatorial Pacific

Atmospheric dust samples were collected on a cruise in the eastern equatorial Pacific during the spring of 1967 in the general area of 8°N to 17°S and 80°W to 110°W. The measured dust loads ranged from 0.04 to 1.2 μg/m3 air, the highest concentrations occurring principally along a track between 5° and 8°N. The mineralogical composition of the samples collected north of the equator differs markedly from the more southerly samples. The northern dust contains a plagioclase as the dominant mineral and subordinate amounts of quartz; in the southerly samples, quartz is prevalent and appreciable quantities of micas, chlorites, and smectites are also present. All samples contain significant amounts of organic material. The relatively high dust loadings encountered along the northern track suggest that windborne dust may be of significance to sedimentation in large areas of the Pacific to the west of Central America.

Infrared absorption spectra of atmospheric dust over an interior desert basin

Based on the qualitative microspectrophotometric analysis of 287 atmospheric dust samples taken within the surface boundary layer over south central New Mexico, U.S.A. from May 1966 through October 1967, a representative infrared absorption spectrum from 4000 to 250 cm−1 (2.5 to 40 μm) is presented. The strongest absorption band is centered at 1027 cm−1 (9,7 μm), within the 1250 to 770 cm−1 (8 to 13 μm) atmospheric window, and is silicate induced. Two other strong broad absorption bands are the carbonate band at 1425 cm−1 (7.0 μm) and the silicate band at 468 cm−1 (21.4 μm). Temporal variations in the absorption spectra of the dust are observed primarily in the varying relative intensities of the 1027 and 1425 cm−1 (9.7 and 7.0 μm) absorption bands and in the occasional enhancement of the 1027 cm−1 (9.7 μm) band caused by sulfates in the dust. This study indicates that there is a close similarity between the absorption spectra of the atmospheric dust and the spectra of the small particle fraction of area soils, and between the representative dust spectrum and a spectrum of a synthetic mixture (by weight) of 80% silicates, 16% carbonates, and 4% nitrates.

Microspectrophotometric technique for obtaining the infrared spectrum of microgram quantities of atmospheric dust

A technique for obtaining full-scale, 4000-250 cm −1 spectra from atmospheric dust samples in the 10–50 μg range is described and a sample dust spectrum is presented.

Analysis of the giant particle component of the atmosphere over an interior desert basin

An investigation of the mineral constituency of the dust component of the atmospheric aerosol over south-central New Mexico, U.S.A., was conducted from November 1964 to August 1965. The 81 atmospheric dust samples, taken near the surface during this period, were analyzed by dispersion staining microscopy to determine the concentrations of quartz, kaolinite, illite, gypsum, and the carbonate family within the “giant partiele” range. These data reveal that high gypsum concentrations are rare despite proximity to one of the world's largest exposed surface deposits of gypsum, that kaolinite and illite concentrations rise with cold frontal passage from the east if the suspected source region is not snow-covered or water-soaked, and that there exist seasonal variations in concentrations. Geometric mean particle concentrations for the 81 samples were: quartz, eight per cent; kaolinite, eight per cent; illite, five per cent; gypsum, three per cent; and carbonates, ten per cent. Comments are made relative to the possible influence of oceanic and extraterrestrial particles on the observed concentrations. DOI: 10.1111/j.2153-3490.1968.tb00367.x

Analysis of the giant particle component of the atmosphere over an interior desert basin

An investigation of the mineral constituency of the dust component of the atmospheric aerosol over south-central New Mexico, U.S.A., was conducted from November 1964 to August 1965. The 81 atmospheric dust samples, taken near the surface during this period, were analyzed by dispersion staining microscopy to determine the concentrations of quartz, kaolinite, illite, gypsum, and the carbonate family within the “giant partiele” range. These data reveal that high gypsum concentrations are rare despite proximity to one of the world's largest exposed surface deposits of gypsum, that kaolinite and illite concentrations rise with cold frontal passage from the east if the suspected source region is not snow-covered or water-soaked, and that there exist seasonal variations in concentrations. Geometric mean particle concentrations for the 81 samples were: quartz, eight per cent; kaolinite, eight per cent; illite, five per cent; gypsum, three per cent; and carbonates, ten per cent. Comments are made relative to the possible influence of oceanic and extraterrestrial particles on the observed concentrations. DOI: 10.1111/j.2153-3490.1968.tb00367.x

PLUTONIUM-239 AND OTHER NUCLIDES IN GROUND-LEVEL AIR AND HUMAN LUNGS DURING SPRING 1962.

Some of the fissile nuclides resulting from nuclear weapon explosions may not undergo fission so these nuclides, together with neutron capture products, may be dispersed from explosions in the atmosphere. Many of these nuclides are alpha emitters and the comparatively high levels of natural alpha activity complicate their identification and measurement. A technique is described that employs an alpha spectrometer for the measurement of Pu239 and Pu240 directly in ground level air at concentrations as low as 5/ 10-17 c/kg despite the presence of naturally occurring Po210. Results are reported from the analysis of atmospheric dust samples and samples of lung tissue. The relation of lung burden and atmospheric concentration of radionuclides is discussed. The total Pu239 inhaled up to June 1962 by a standard man in England was calculated as of the order of 5 pc.

Measurements of air radioactivity in Italy and their relation to the first Sahara atomic explosion.

ON the occasion of the French atomic explosion of February 13, 1960, in the Sahara, a control system of radioactivity in the air was set up covering the whole of Italy. The controlling stations of the system were equipped to collect samples of atmospheric dust by means of suction through a filter. The β-activity of the samples was measured 120 hr. after they had been collected.

Gamma-ray analysis of atmospheric dust samples

The presence of nuclear weapon debris in the air over Canada following the tests in the spring of 1957 and 1958 was demonstrated by γ-ray spectral studies. Peaks from fission products Zr 95, Nb 95, Ru 103, Ce 141, Ce 144 and Cs 137, with half-lives of several days and longer, were identified. The same peaks were found in a sample of house dust. Very long-lived fission products such as caesium-137 were not of sufficient activity to permit identification until the samples had decayed for several months.