ABSTRACT

Several studies published in the 1950s and 1960s noted the

particular role of the unattached radioactivity of radon decay

products (Knutson, 1988; Hopke, 1989). It was postulated that

upon inhalation, the high mobility (large diffusion coefficient) of

this radioactivity should cause significant diffusion in the lung

airways of such radioactivity and hence the main biological effect

of the radiation, to be in trachea. This was, in fact, confirmed

when medical researchers observed the localization of lung cancer

seen in miners in the respiratory systems of miners. Although

the effects of unattached fraction were documented long ago, they

are still not fully understood today, especially in connection with

the danger of radon in homes. To this day, a few instruments for

use in measuring this type of radiation have been developed for

commercial production.