Video display terminals and radon.
Recent reports indicate that video display terminals (VDTs) can collect radon progeny from the air. This occurs especially when they are turned off and may have negative electric fields which attract positively charged radioactive dust. We have studied this phenomenon in detail and evaluated various techniques for removing the gettered radioactivity while the video display terminal is both off and on. We have evaluated what happens when the video display terminal is switched, thereby reversing the electric field near the screen. We have also studied possible inhalation effects by a video display terminal operator during field reversal and find that although some radioactivity may be released during the cycle, room air currents redistribute it into the room with no detectable levels being inhaled by users.
Alterações cromossômicas causadas pela radiação dos monitores de vídeo de computadores
OBJETIVO: Em decorrencia dos questionamentos sobre o efeito deleterio das radiacoes emitidas pelo campo eletromagnetico (CEM) dos tipos ELF (extremely low frequency) e VLF (very low frequency) transmitidas pelos monitores de video dos computadores (CRT), foi avaliada a frequencia de anomalias cromossomicas estruturais e a cinetica do ciclo celular em individuos expostos por seu trabalho a radiacao dos CRT. METODOS: A pesquisa de aberracoes cromossomicas foi realizada em 2.000 metafases de primeira divisao celular obtidas de culturas de 48h de linfocitos de sangue venoso periferico de dez individuos expostos ao CRT (grupo E) e de dez controles (grupo C). A cinetica do ciclo celular foi pesquisada pelos indices mitotico (IM) e de proliferacao celular (IPC). RESULTADOS: A analise estatistica evidenciou frequencias significativamente maiores de metafases com anomalias cromossomicas (E=5,9%; C=3,7%) e anomalias/celula (E=0,066±0,026; C=0,040±0,026) nos individuos expostos aos CRTs. As alteracoes citogeneticas mais comuns foram as quebras cromatidicas, com frequencia de 0,034±0,016 no grupo E e de 0,016±0,015 no grupo C. As frequencias de IM e IPC nao apresentaram diferencas significantes entre os grupos avaliados. CONCLUSOES: Os resultados sugerem um efeito genotoxico do CEM emitido pelos CRTs devido a frequencia mais elevada de quebras cromatidicas, enfatizando a necessidade de haver um numero maior de estudos com diferentes tecnicas que vise a investigar a acao do CEM sobre o material genetico.
Properties, Measurement, and Bioclimatic Action of “Small” Multimolecular Atmospheric Ions
Publisher Summary This chapter discusses properties, measurements, and bioclimatic action of small multimolecular atmospheric ions. It has been known in gas discharge physics that in ionized gases at higher pressures not only monomolecular or monatomic ions can be found but also a comparatively small number of heavier ions. The mobilities of these ions are considerably smaller than those of the monomolecular ions. Air ions are chiefly formed by ionization of single air component molecules and following reaction processes between electrons, ions, and/or the different molecules or atoms of the air. In physical and biological experiments the distance between the ion source and the ion counter or test object is of importance. The essential part of an ion counter is a condenser through which a stream of the air to be analyzed is maintained. The ion collector assembly is enclosed inside a rectangular metal duct which serves as a guard shield against stray electric fields. It is suggested that to reduce grid leak current and misreadings due to undesired photoeffect the electrometer tubes must be guarded from contamination and operated in a dark dry sealed enclosure.