“…Air pollution, particularly due to rare gas radio-isotopes in and around nuclear facilities, [282][283][284] continues to be a topic of concern and the role of radio-colloids 285,286 in the airborne distribution of radio-isotopes has been discussed. The isotopes of xenon (131 m, 133 m, 133 and 135) have been monitored in detail 287 for verification of compliance with the nuclear test ban treaty, but it is difficult to distinguish the isotope pattern from a bomb from that due to a medical isotope facility.…”