Published March 1979 | Version v1
Report Open

Size distribution of natural aerosols and radioactive particles issued from radon, in marine and hardly polluted urban atmospheres

Description

With a view to studying the natural radioactive particles produced by atttachment of 222Rn daughters on environmental aerosol particles, the behaviours of CASELLA MK2 and ANDERSEN cascade impactors were first investigated. Their characteristic stage diameters were determined and size distributions of airborne particles were obtained in various situations. Moreover, an experimental and automatic equipment for measuring radon was devised and a method was developed in order to evaluate RaA, RaB, RaC concentrations in the free atmosphere. A degree of radioactive desequilibrium between 222Rn and its daughters, more important than that in other locations was thus demonstrated. Furthermore, by means of various aerosol collection systems (ion tubes, diffusion batteries, cascade impactors, filters), the cumulative size distribution of natural radioactivity was established in the air, at ground level. Finally, from a theory of attachment of small radioactive ions on atmospheric particles, a tentative explanation of experimental results was made

Availability note (English)

MF available from INIS under the Report Number.

Abstract (French)

Dans le but d'etudier les aerosols radioactifs naturels formes par la fixation des descendants du radon sur les particules en suspension dans l'air, on examine tout d'abord le comportement des impacteurs en cascade CASELLA MK2 et ANDERSEN pour les aerosols atmospheriques. On determine ainsi les diametres caracteristiques de leurs differents etages, et on presente une etude granulometrique des particules de l'atmosphere dans diverses situations. Parallelement, on met au point un dispositif electromecanique permettant de doser automatiquement le radon et on developpe une methode a partir de laquelle les concentrations en RaA, RaB, RaC sont evaluees. On met ainsi en evidence un degre de desequilibre radioactif plus eleve que celui habituellement rencontre dans d'autres sites. D'autre part, au moyen de dispositifs classiques de prelevement (tubes a ions, batteries de diffusion, impacteurs en cascade, filtres), on etablit experimentalement la repartition granulometrique cumulee de la radioactivite naturelle dans l'air au niveau du sol. Enfin, on essaie d'interpreter les resultats experimentaux, a partir d'une theorie de la fixation des petits ions radioactifs sur les particules naturelles de l'air

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Additional details

Additional titles

Original title (French)
Repartition granulometrique de l'aerosol naturel et des particules radioactives issues du radon, en atmosphere maritime et urbaine peu polluee

Publishing Information

Imprint Pagination
187 p.
Report number
CEA-R--4965