The determination of lead in environmental air using a radioisotope X-ray-fluorescence unit

The feasibility for the development of a portable radioisotope excited X-ray fluorescence unit, able to detect Pb in air samples, was studied. The unit employs a 0.6-mCi 109Cd source and a Xe-filled proportional detector. The sensitivity of the method was found to be 15 micrograms of lead per cubic metre of air. Suggestions are also made for the improvement of the sensitivity.