The concentration of radon in the open air and interiors and in sub-so
il of Delta sites was determined by using solid state nuclear track de
tectors (SSNTDs). Radon concentration measurements in air in Delta, no
rth Cairo, were performed by open and filtered detectors, with small v
olume and CR-39 plastic film. The equilibrium factor F and the dose eq
uivalent were calculated by using the track densities of open and filt
ered SSNTDs.